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Genetic history of Africa
Genetic history of Africa
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Population structure of African populations in a broad context. ADMIXTURE analysis of 2,194 individuals from 81 populations for 16,420 SNPs reveals both well-established and novel ancestry components in African populations.

The genetic history of Africa summarizes the genetic makeup and population history of African populations in Africa, composed of the overall genetic history, including the regional genetic histories of North Africa, West Africa, East Africa, Central Africa, and Southern Africa, as well as the recent origin of modern humans in Africa. The Sahara served as a trans-regional passageway and place of dwelling for people in Africa during various humid phases[1][2][3] and periods throughout the history of Africa.[4][5] It also served as a biological barrier that restricted geneflow between the northern and central parts of Africa since its desertification, contributing to the diverse and distinct population structures on the continent. Nonetheless, this did not stop contact between peoples north and south of the Sahara at various points, especially in prehistoric times when the climate conditions were warmer and wetter.[6]

Overview

[edit]
(A) the origin of the 46 African ethnic groups used in the analysis; ethnic groups from similar regions are given the same colour, but different shapes. (B) PCA shows that the first major axis of variation in Africa (PC1, y-axis) splits southern groups from the rest of Africa, each symbol represents an individual; PC2 (x-axis) reflects ethno-linguistic differences, with Niger-Congo and Nilo-Saharan speakers split from Afroasiatic speakers. (C) The third principal component (PC3, x-axis) represents geographical separation of Niger-Congo speakers, forming a cline from west to east Africans.

The peoples of Africa are characterized by regional genetic substructure and heterogeneity, depending on the respective ethno-linguistic identity, and, in part, explainable by the "multiregional evolution" of modern human lineages in various multiple regions of the African continent, as well as later admixture events, including back-migrations from Eurasia, of both highly differentiated West and East Eurasian components.[7]

Africans' genetic ancestry is largely partitioned by geography and language family, with populations belonging to the same ethno-linguistic groupings showing high genetic homogeneity and coherence. Gene flow, consistent with both short- and long-range migration events followed by extensive admixture and bottleneck events, have influenced the regional genetic makeup and demographic structure of Africans. The historical Bantu expansion had lasting impacts on the modern demographic make up of Africa, resulting in a greater genetic and linguistic homogenization.[8][9] Genetic, archeologic, and linguistic studies added extra insight into this movement: "Our results reveal a genetic continuum of Niger–Congo speaker populations across the continent and extend our current understanding of the routes, timing and extent of the Bantu migration."[10]

Overall, different African populations display genetic diversity and substructure, but can be clustered in distinct but partially overlapping groupings:[11][12][13][9][14][15]

  • Khoisan or 'South African hunter-gatherers' from Southern Africa represented by the Khoisan peoples; they are associated with the deepest divergence (c. 270,000 years ago) of human genetic diversity, forming a distinct cluster of their own. They subsequently diverged into a Northern and Southern subgroup, c. 30,000 years ago.[a]
  • 'Central African hunter-gatherers' or 'Rain forest hunter-gatherers' (Pygmies) of Central Africa, represented by the Biaka and Mbuti; associated with another deep divergence (c. 220,000 years ago). They subsequently diverged into an Eastern and Western subgroup, c. 20,000 years ago.[b]
  • "Ancestral Eurasians" represent the ancestral population of modern Eurasians shortly before the Out-of-Africa expansion; they are inferred to have diverged from other African populations, most likely somewhere in Northeast Africa, c. 70,000 years ago.
  • The various Afroasiatic-speakers from Northern Africa and the Horn of Africa, are suggested to have diverged from other African groups c. 50,000 years ago, but currently insufficient data and geneflow from other groups complicate an accurate estimation of the divergence date.[16] Afroasiatic-speaking populations also display variable amounts of West Asian (primarily Natufian-like, but also Neolithic Anatolian and Iranian) admixtures from Eurasian backflow movements, with the remainder being primarily from autochthonous African genetic clusters, associated with Nilotic-like ancestry. They also display affinity for the Paleolithic North African Taforalt specimens of the Iberomaurusian culture.[c]
  • 'Eastern African hunter-gatherers', represented by Hadza, Sandawe, Omotic-speakers, and the ancient Mota specimen; their phylogenetic relationship to other populations is not clear, but they display affinity to modern East and West African populations, and harbor Khoesan-like geneflow along a Northeast to Southwest cline, as well as later (West) Eurasian admixtures, but at lower amounts than among Afroasiatic-speakers.[d]
  • "Ancient East Africans" or "Ancestral West/East Africans" associated with the common ancestor of modern Niger-Congo and Nilo-Saharan-speakers originated around 28,000 years ago, likely in the Nile Valley region. They subsequently diverged at c. 18,000 years ago into the ancestors of West and West-Central African Niger-Congo and Bantu-speakers, and into the East African Nilo-Saharan/Nilotic-speakers. They represent the dominant and most widespreaded ancestry component of modern Africa, and are associated with relative recent population expansions linked to agriculture and pastoralist lifestyles. Genetic data indicates affinity for older hunter-gatherer groups in East Africa, but their exact relationship remains unclear.[11][e] There is evidence for limited geneflow (9–13%) from a human ghost lineage, referred to as 'West African foragers' with a deeper or equally deep divergence time than 'Khoisan hunter-gatherers', into modern West Africans.[17][18]
  • Austronesian-speaking Malagasy people in Madagascar have received significant East/Southeast Asian admixture associated with the Austronesian expansion, with the remainder ancestry being primarily associated with West-Central and East African components. The estimated date of geneflow between these sources is c. 2,200 years ago.[19]
Geographic location of the samples analyzed in this study (A). PCA of the Khoe-San individuals, Eurasians, West and East Africans before (unmasked, B) and after (masked, C) applying the local ancestry pipeline (146,696 independent SNPs).

Indigenous Africans

[edit]

The term 'indigenous Africans' refers to the populations with primarily indigenous (non-Eurasian) ancestries, consisting of Niger–Congo speakers, Nilo-Saharan speakers, the divergent and diverse Khoisan grouping, as well as of several unclassified or isolated ethnolinguistic groupings (see unclassified languages of Africa). The origin of the Afroasiatic languages remains disputed, with some proposing a Middle Eastern origin, while others support an African origin[20] with varying degrees of Eurasian and African components.[16] The Austronesian languages originated in southern East Asia, and later expanded outgoing from the Philippines.

PCA plot of genetic variation of worldwide populations. (A) Geographic coordinates of 53 populations. (B) Procrustes-transformed PCA plot of genetic variation.[21]

The Niger–Congo languages probably originated in or near the area where these languages were spoken prior to Bantu expansion (i.e. West Africa or Central Africa). Its expansion may have been associated with the expansion of agriculture, in the African Neolithic period, following the desiccation of the Sahara in c. 3500 BCE. Proto-Niger-Congo may have originated about 10,000 years before present in the "Green Sahara" of Africa (roughly the Sahel and southern Sahara), and that its dispersal can be correlated with the spread of the bow and arrow by migrating hunter-gatherers, which later developed agriculture.[22][23][24]

Although the validity of the Nilo-Saharan family remains controversial, the region between Chad, Sudan, and the Central African Republic is seen as a likely candidate for its homeland prior to its dispersal around 10,000–8,000 BCE.[25]

The Southern African hunter-gatherers (Khoisan) are suggested to represent the autochthonous hunter-gatherer population of southern Africa, prior to the expansion of Bantu-speakers from Western/Central Africa and East African pastoralists. Khoisan show evidence for Bantu-related admixture, ranging from nearly ~0% to up to ~87.1%.[26]

Out-of-Africa event

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Human migration routes following Out-of-Africa.
Most modern Africans display a high level of genetic homogeneity, but contributions from Eurasian populations are substantial, mostly concentrated in the Northeastern part of Africa and Madagascar.

The "recent African origin of modern humans" proposes a "single origin" of Homo sapiens within Africa. Recent genetic and archeologic data suggests that Homo sapiens-subgroups originated in multiple regions of Africa, not confined to a single sub-region of origin, with the last common ancestor of all modern humans expanding from a single region absorbing or replacing various deep lineages (described as archaic ghosts). The H. sapiens ancestral to proper Eurasians most likely left Northeastern Africa between 50,000 and 100,000 years ago.[27] The "recent African origin" model proposes that all modern non-African populations descend from one or several waves of H. sapiens that left Africa 70,000–60,000 years ago.[28][29][30][31]

According to serial founder model, the earliest-branching non-African lineages are expected to have expanded in the Middle East, after the Out-of-Africa event (a), but have their deepest divergence in modern-day East or Southeast Asia (b), suggesting either rapid diversification and substructure within the early Eurasians, or replacement and loss of deep lineages in Western Eurasia. Simplified Y tree is shown as reference for colours.[32]

According to Durvasula et al. (2020), there are indications that 2% to 19% (≃6.6 to 7.0%) of the DNA of West African populations may have come from an unknown archaic hominin which split from the ancestor of humans and Neanderthals between 360 kya to 1.02 mya. However, Durvasula et al. (2020) also suggests that at least part of this archaic admixture is also present in Eurasians/non-Africans, and that the admixture event or events range from 0 to 124 ka B.P, which includes the period before the Out-of-Africa migration and prior to the African/Eurasian split (thus affecting in part the common ancestors of both Africans and Eurasians/non-Africans).[33][34][35] Chen et al. (2020) found that Africans have higher Neanderthal ancestry than previously thought. 2,504 African samples from all over Africa were analyzed and tested on Neanderthal ancestry. All African samples showed evidence for minor Neanderthal ancestry, but always at lower levels than observed in Eurasians.[36]

Geneflow between Eurasian and African populations

[edit]
Pre-Neolithic and Neolithic migration events in Africa.[15]
A visual summary of the main admixture movements into and within Africa.[37]

Significant Eurasian admixture is found in Northern Africa, and among specific ethnic groups of the Horn of Africa, Northern Sudan, the Sahel region, as well as among the Malagasy people of Madagascar. Various genome studies found evidence for multiple prehistoric back-migrations from various Eurasian populations and subsequent admixture with native groups.[38] West Eurasian-associated geneflow arrived to Northern Africa during the Paleolithic (30,000 to 15,000 years ago), followed by other pre-Neolithic and Neolithic migration events. Genetic data on the Taforalt samples "demonstrated that Northern Africa received significant amounts of gene-flow from Eurasia predating the Holocene and development of farming practices". Medieval geneflow events, such as the Arab expansion also left traces in various African populations.[27][15][39] Pickrell et al. (2014) indicated that Western Eurasian ancestry eventually arrived through Northeast Africa (particularly the Horn of Africa) to Southeast Africa and Southern Africa.[40]

Ramsay et al. (2018) also found evidence for significant Western Eurasian admixture in various parts of Africa, from both ancient and more recent migrations, being highest among populations from Northern Africa, and some groups of the Horn of Africa:[41]

In addition to the intrinsic diversity within the continent due to population structure and isolation, migration of Eurasian populations into Africa has emerged as a critical contributor to the genetic diversity. These migrations involved the influx of different Eurasian populations at different times and to different parts of Africa. Comprehensive characterization of the details of these migrations through genetic studies on existing populations could help to explain the strong genetic differences between some geographically neighbouring populations.

This distinctive Eurasian admixture appears to have occurred over at least three time periods with ancient admixture in central west Africa (e.g., Yoruba from Nigeria) occurring between ~7.5 and 10.5 kya, older admixture in east Africa (e.g., Ethiopia) occurring between ~2.4 and 3.2 kya and more recent admixture between ~0.15 and 1.5 kya in some east African (e.g., Kenyan) populations.

Subsequent studies based on LD decay and haplotype sharing in an extensive set of African and Eurasian populations confirmed the presence of Eurasian signatures in west, east and southern Africans. In the west, in addition to Niger-Congo speakers from The Gambia and Mali, the Mossi from Burkina Faso showed the oldest Eurasian admixture event ~7 kya. In the east, these analyses inferred Eurasian admixture within the last 4000 years in Kenya.[41]

Ancestral components of various human populations using a four-way Admixture model. European and Middle Eastern (Western Eurasian) ancestry is found in many African groups.

There is no definitive agreement on when or where the original homeland of the Afroasiatic language family existed. Some have suggested that they were spread by people with largely West-Eurasian ancestry during the Neolithic Revolution, towards Northern Africa and the Horn of Africa, outgoing from the Middle East, specifically from the Levant.[42] Others argue that the first speakers of Proto-Afroasiatic were based in Northeast Africa because that region includes the majority of the diversity of the Afroasiatic language family and has very diverse groups in close geographic proximity, which is sometimes considered a telltale sign for a linguistic geographic origin.[43] A subset of the Proto-Afroasiatic population would have migrated to the Levant during the late Paleolithic, merging with local West-Eurasians and resulting in a population which would later give rise to Natufian culture, associated with the early development of agriculture and early Afroasiatic languages, or specifically pre-proto-Semitic.[44][45][page needed][46][47][48][49] In addition, Y-haplogroup sub-lineage E-M215 (also known as "E1b1b) and its derivative E-M35 are quite common among Afroasiatic speakers, and southwestern Ethiopia is a plausible source of these haplogroups.[50] Under this African model, the linguistic group and carriers of this lineage would have arisen and dispersed together from Northeast Africa in the Mesolithic, plausibly having already developed subsistence patterns of pastoralism and intensive plant usage and collection.[51][52][53][54]

The Near-Eastern agriculturalist hypothesis does not account for the domestication of plants endemic to the Horn of Africa such as teff, ensete, and Niger seed, nor does it account for the lack of evidence of intrusive agricultural populations or for the growing of wheat, barley, or sorghum in that region prior to 3000 B.C.[55] According to historian and linguist Christopher Ehret, the form of intensive plant collection practiced by the Proto-Afroasiatic population in Northeast Africa may have been a precursor to the other agricultural practices that would later independently develop in the Fertile Crescent and the Horn of Africa.[48][56][57]

Proposed migration routes of paternal lineage E.

Horn of Africa

[edit]

While many studies conducted on Horn of Africa populations estimate a West-Eurasian admixture event around 3,000 years ago,[58][41][40][59] Hodgson et al. (2014) found a distinct West-Eurasian ancestral component among studied Afroasiatic-speaking groups in the Horn of Africa (and to a lesser extent in North Africa and West Asia), most prevalent among the ethnic Somali. This ancestral component dubbed "Ethio-Somali" is most closely related to the "Maghrebi" (peaking in Tunisians) component and is believed to have diverged from other non-African ancestries around 23,000 years ago, and migrated back to Africa prior to developing agriculture (12–23 ka) from the Near East. This population would have crossed via the Sinai Peninsula and then split into two, with one branch continuing west across North Africa and the other heading south into the Horn of Africa. The authors propose that the "Ethio-Somali" component may have been a substantial ancestral component of the Proto-Afroasiatic-speaking population. Later migration from Arabia into the HOA beginning around 3 ka would explain the origin of the Ethiosemitic languages at this time.[46] An mtDNA analysis by Gandini et al. (2016) has produced additional evidence in support of a pre-agricultural back-migration from West-Eurasia into the Horn of Africa with an estimated date of arrival into the Horn of Africa in the early Holocene, possibly as a result of obsidian exchange networks across the Red Sea.[60] Hodgson et al. also confirmed the existence of an ancestral component indigenous to the Horn of Africa - "Ethiopic" or "Omotic" (Pagani et al.) - which is most prevalent among speakers of the Omotic branch of Afroasiatic in southwestern Ethiopia.[46][58] This lineage is associated with that of a 4,500 year-old fossil (Mota) found in a cave in southwestern Ethiopia, which has high genetic affinity to modern Ethiopian groups, especially the endogamous blacksmith caste of the Omotic Aari people. Like Mota, Aari blacksmiths do not show evidence for admixture with West-Eurasians, demonstrating a degree of population continuity in this region for at least 4,500 years. In a comparative analysis of Mota's genome referencing modern populations, Gallego et al. (2016) concluded that the divergence of Omotic from other Afroasiatic languages may have resulted from the relative isolation of its speakers from external groups.[61]

In an analysis of 68 Ethiopian ethnic groups, Lopez et al. (2021) revealed that several groups belonging to the three AA classifications of Cushitic, Omotic and Semitic show high genetic similarity to each other on average. Furthermore, the Nilo-Saharan speakers in the southwest shared more recent ancestry with Bantu and Nilotics, in contrast Afro-Asiatic speakers in the northeast shared more recent ancestry with Egyptians and other West Eurasians. The data also supported widespread recent intermixing among various ethnic groups.[62]

Madagascar

[edit]
Austronesian expansion, outgoing from Taiwan and the northern Philippines.

Specific East Asian-related ancestry is found among the Malagasy speakers of Madagascar at a medium frequency. The presence of this East Asian-related ancestry is mostly linked to the Austronesian peoples expansion from Southeast Asia.[63][64][65][66] The peoples of Borneo were identified to resemble the East Asian voyagers, who arrived on Madagascar. East Asian ancestry among Malagasy people was estimated at a mean average of 33%, but as high as ~75% among some Highlander groups and upper caste groups.[67][68][66]

Northern Africa

[edit]

Dobon et al. (2015) identified an autosomal ancestral component that is commonly found among modern Afroasiatic-speaking populations (as well as Nubians) in Northeast Africa. This Coptic component peaks among Copts in Sudan, which is differentiated by its lack of Arab influence, but shares common ancestry with the North African/Middle Eastern populations. It appears alongside a component that defines Nilo-Saharan speakers of southwestern Sudan and South Sudan.[69] Arauna et al. (2017), analyzing existing genetic data obtained from Northern African populations, such as Berbers, described them as a mosaic of North African (Taforalt), Middle Eastern, European (Early European Farmers), and Sub-Saharan African-related ancestries.[70]

Chen et al. (2020) analyzed 2,504 African samples from all over Africa, and found archaic Neanderthal ancestry, among all tested African samples at low frequency. They also identified a European-related (West-Eurasian) ancestry segment, which seems to largely correspond with the detected Neanderthal ancestry components. European-related admixture among Africans was estimated to be between ~0% to up to ~30%, with a peak among Northern Africans.[71] According to Chen et al. (2020), "These data are consistent with the hypothesis that back-migration contributed to the signal of Neanderthal ancestry in Africans. Furthermore, the data indicates that this back-migration came after the split of Europeans and East Asians, from a population related to the European lineage."[71]

There is a minor geneflow from North Africa in parts of Southern Europe, this is supported by the presence of an African-specific mitochondrial haplogroup among one of four 4,000 year old samples.[72] Multiple studies found also evidence for geneflow of African ancestry towards Eurasia, specifically Europe and the Middle East. The analysis of 40 different West-Eurasian populations found African admixture at a frequency of 0% to up to ~15%.[73][74][75][76]

Western Africa

[edit]

Hollfelder et al. (2021) concluded that West African Yoruba people, which were previously used as "unadmixed reference population" for indigenous Africans, harbor minor levels of Neanderthal ancestry, which can be largely associated with back-migration of an "Ancestral European-like" source population.[7]

A genome-wide study of a Fulani community from Burkina Faso inferred two major admixture events in this group, dating to ~1800 ya, and 300 ya. The first admixture event took place between the West African ancestors of the Fula and ancestral North African nomadic groups. The second admixture event, relatively recent, inferred a source from Southwestern Europe, or suggests either an additional gene flow between the Fulani and Northern African groups, who carry admixture proportions from Europeans.[77] Sahelian populations like the Toubou also showed admixture coming from Eurasians.[78]

Southern Africa

[edit]

Low levels of West Eurasian ancestry (European or Middle Eastern) are found in Khoe–Kwadi Khoesan-speakers. It could have been acquired indirectly by admixture with migrating pastoralists from East Africa. This hypothesis of gene flow from eastern to southern Africa is further supported by other genetic and archaeological data documenting the spread of pastoralism from East to South Africa.[79]

Regional genomic overview

[edit]

North Africa

[edit]

Archaic Human DNA

[edit]

While Denisovan and Neanderthal ancestry in non-Africans outside of Africa are more certain, archaic human ancestry in Africans is less certain and is too early to be established with certainty.[80]

Ancient DNA

[edit]

Daniel Shriner (2018), using modern populations as a reference, showed that the Natufians carried 61.2% Arabian, 21.2% Northern African, 10.9% Western Asian, and a small portion of Eastern African ancestry at 6.8%, which is associated with the modern Omotic-speaking groups found in southern Ethiopia.[50]

Egypt
[edit]

Khnum-aa, Khnum-Nakht, Nakht-Ankh and JK2911 carried maternal haplogroup M1a1.[81][58]

Djehutynakht (10A) carried maternal haplogroup U5b2b5.[82] JK2888 carried maternal haplogroup U6a2.[58]

Thuya, Tiye, Tutankhamen's mother, and Tutankhamen carried the maternal haplogroup K.[81]

JK2134 carried maternal haplogroup J1d[58] and JK2887 carried maternal haplogroup J2a1a1.[58]

Amenhotep III, Akhenaten, and Tutankhamen carried the paternal haplogroup R1b.[81]

Ramesses III and "Unknown Man E", possibly Pentawere, carried paternal haplogroup E1b1a.[81][83][84]

JK2134 and JK2911 carried paternal haplogroup J.[58]

Takabuti carried maternal haplogroup H4a1[85] and YM:KMM A 63 carried maternal haplogroup HV.[86]

OM:KMM A 64 carried maternal haplogroup T2c1a.[86]

JK2888 carried paternal haplogroup E1b1b1a1b2.[58]

In 2025, biochemist Jean-Philippe Gourdine reviewed genetic data on the Ancient Egyptian populations in the international scholarly publication, General History of Africa Volume IX. Expanding on a previous STR analysis co-performed with Keita, on the Amarna royal mummies which included Tutankhamun, Gourdine stated the analysis had found “that they had strong affinities with current sub-Saharan populations: 41 per cent to 93.9 per cent for sub-Saharan Africa, compared to 4.6 per cent to 41 per cent for Eurasia and 0.3 per cent to 16 per cent for Asia (Gourdine, 2018).” He also referenced comparable analysis conducted by DNA Tribes company, which specialized in genetic genealogy and had large datasets, with the latter having identified strong affinities between the Amarna royal mummies and Sub-Saharan African populations.[87]

E1b1b is the most common paternal haplogroup across Africa, including Egypt, with modern genetic studies rooting the origin of the E haplogroup in East Africa.[88]

Genetic analysis of a modern Upper Egyptian population in Adaima by Eric Crubézy had identified genetic markers common across Africa, with 71% of the Adaima samples carrying E1b1 haplogroup and 3% carrying the L0f mitochondrial haplogroup.[89] A secondary review, published in UNESCO General History of Africa Volume IX, in 2025 noted the results were preliminary and need to be confirmed by other laboratories with new sequencing methods.[90] This was supported by an anthropological study which found the notable presence of dental markers, characteristic of Khoisan people, in a predynastic-era cemetery at Adaïma.[91] The genetic marker E1b1 was identified in a number of genetic studies to have wide distribution across Egypt, with "P2/215/M35.1 (E1b1b), for short M35, likely also originated in eastern tropical Africa, and is predominantly distributed in an arc from the Horn of Africa up through Egypt".[92] Multiple STR analysis of the Amarna royal mummies (including Rameses III, Tutankhamun and Amenhotep III) were deployed to estimate their ethnicity have found they had strong affinities with modern Sub-Saharan populations. Nonetheless, these forms of analysis were not exhaustive as only 8 of the 13 CODIS markets were used.[93]

Libya
[edit]

At Takarkori rockshelter, in Libya, two naturally mummified women, dated to the Middle Pastoral Period (7000 BP), carried basal maternal haplogroup N.[94]

Morocco
[edit]

Van de Loorsdrecht et al. (2018) found that of seven samples of Taforalts of Morocco, radiocarbon dated to between 15,100 cal BP and 13,900 cal BP, six were found to carry maternal haplogroup U6a, and one was found to carry maternal haplogroup M1b. All six males were found to carry paternal haplogroup E1b1b, and they harbored 63.5% Natufian-related ancestry and 36.5% Sub-Saharan African-related ancestry. The Sub-Saharan component is most strongly drawn out by modern West African groups such as the Yoruba and the Mende. The samples also contain an additional affinity to South, Central, and East African outgroups that cannot be explained by any known ancient or modern populations.[95] When projected onto a principal component analysis graph of African and west Eurasian populations, the Taforalt individuals form a distinct cluster in an intermediate position between modern North Africans (e.g., Berbers, Mozabites, Saharawis) and East Africans (e.g., Afars, Oromos, Somalis).[95] Jeong (2020), when comparing the Taforalt people of the Iberomaurusian culture to modern populations, found that the Taforalt's Sub-Saharan African genetic component may be best represented by modern West Africans (e.g., Yoruba).[96]

Y-Chromosomal DNA

[edit]

Mitochondrial DNA

[edit]

Amid the Holocene, including the Holocene Climate Optimum in 8000 BP, Africans bearing haplogroup L2 spread within West Africa and Africans bearing haplogroup L3 spread within East Africa.[97] As the largest migration since the Out of Africa migration, migration from Sub-Saharan Africa toward the North Africa occurred, by West Africans, Central Africans, and East Africans, resulting in migrations into Europe and Asia; consequently, Sub-Saharan African mitochondrial DNA was introduced into Europe and Asia.[97] During the early period of the Holocene, 50% of Sub-Saharan African mitochondrial DNA was introduced into North Africa by West Africans and the other 50% was introduced by East Africans.[97] During the modern period, a greater number of West Africans introduced Sub-Saharan African mitochondrial DNA into North Africa than East Africans.[97]

Mitochondrial haplogroups L3, M, and N are found among Sudanese peoples (e.g., Beja, Nilotics, Nuba, Nubians), who have no known interaction (e.g., history of migration/admixture) with Europeans or Asians; rather than having developed in a post-Out-of-Africa migration context, mitochondrial macrohaplogroup L3/M/N and its subsequent development into distinct mitochondrial haplogroups (e.g., Haplogroup L3, Haplogroup M, Haplogroup N) may have occurred in East Africa at a time that considerably predates the Out-of-Africa migration event of 50,000 BP.[98]

Autosomal DNA

[edit]

Medical DNA

[edit]

The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[99]

Lactase persistence
[edit]

Neolithic agriculturalists, who may have resided in Northeast Africa and the Near East, may have been the source population for lactase persistence variants, including –13910*T, and may have been subsequently supplanted by later migrations of peoples.[100] The Sub-Saharan West African Fulani, the North African Tuareg, and European agriculturalists, who are descendants of these Neolithic agriculturalists, share the lactase persistence variant –13910*T.[100] While shared by Fulani and Tuareg herders, compared to the Tuareg variant, the Fulani variant of –13910*T has undergone a longer period of haplotype differentiation.[100] The Fulani lactase persistence variant –13910*T may have spread, along with cattle pastoralism, between 9686 BP and 7534 BP, possibly around 8500 BP; corroborating this timeframe for the Fulani, by at least 7500 BP, there is evidence of herders engaging in the act of milking in the Central Sahara.[100]

West Africa

[edit]

Archaic Human DNA

[edit]

Archaic traits found in human fossils of West Africa (e.g., Iho Eleru fossils, which dates to 13,000 BP) and Central Africa (e.g., Ishango fossils, which dates between 25,000 BP and 20,000 BP) may have developed as a result of admixture between archaic humans and modern humans or may be evidence of late-persisting early modern humans.[80] While Denisovan and Neanderthal ancestry in non-Africans outside of Africa are more certain, archaic human ancestry in Africans is less certain and is too early to be established with certainty.[80]

Ancient DNA

[edit]

As of 2017, human ancient DNA has not been found in the region of West Africa.[101] As of 2020, human ancient DNA has not been forthcoming in the region of West Africa.[96]

Y-Chromosomal DNA

[edit]

Eight male individuals from Guinea Bissau, two male individuals from Niger, one male individual from Mali, and one male individual from Cabo Verde carried haplogroup A1a.[102]

As a result of haplogroup D0, a basal branch of haplogroup DE, being found in three Nigerian men, it may be the case that haplogroup DE, as well as its sublineages D0 and E, originated in Africa.[103]

As of 19,000 years ago, Africans, bearing haplogroup E1b1a-V38, likely traversed across the Sahara, from east to west.[104] E1b1a1-M2 likely originated in West Africa or Central Africa.[105]

Mitochondrial DNA

[edit]

Around 18,000 BP, Mende people, along with Gambian peoples, grew in population size.[106]

In 15,000 BP, Niger-Congo speakers may have migrated from the Sahelian region of West Africa, along the Senegal River, and introduced L2a1 into North Africa, resulting in modern Mauritanian peoples and Berbers of Tunisia inheriting it.[107]

Between 11,000 BP and 10,000 BP, Yoruba people and Esan people grew in population size.[106]

As early as 11,000 years ago, Sub-Saharan West Africans, bearing macrohaplogroup L (e.g., L1b1a11, L1b1a6a, L1b1a8, L1b1a9a1, L2a1k, L3d1b1a), may have migrated through North Africa and into Europe, mostly into southern Europe (e.g., Iberia).[108]

Autosomal DNA

[edit]

During the early period of the Holocene, in 9000 BP, Khoisan-related peoples admixed with the ancestors of the Igbo people, possibly in the western Sahara.[109][110]

Between 2000 BP and 1500 BP, Nilo-Saharan-speakers may have migrated across the Sahel, from East Africa into West Africa, and admixed with Niger-Congo-speaking Berom people.[111] In 710 CE, West African-related populations (e.g., Niger-Congo-speaking Berom people, Bantu-speakers) and East African-related populations (Nilo-Saharan-speaking Ethiopians, Nilo-Saharan-speaking Chadians) admixed with one another in northern Nigeria and northern Cameroon.[112]

Fan et al. (2019) found that the Fulani people show genetic affinity to isolated Afroasiatic-speaking groups in Eastern Africa, specifically Omotic-speakers such as the Aari people. While the Fulani have nearly exclusive indigenous African ancestry (defined by West and East African ancestry), they also show traces of West-Eurasian-like admixture, supporting an ancestral homeland somewhere in North or Eastern Africa, and westwards expansion during the Neolithic, possibly caused by the arrival and expansion of West-Eurasian-related groups.[113] Fan et al. (2023) found that the Fulani, who have 50% Amhara-related and 50% Tikari-related ancestry as well as occupy regions such as West Africa, Central Africa, and the Sudan as nomadic herders, may have initially been Afroasiatic speakers that subsequently underwent language replacement and became Niger-Congo speakers.[114]

Medical DNA

[edit]

The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[99] Throughout Sub-Saharan Africa, genetic adaptation (e.g., rs334 mutation, Duffy blood group, increased rates of G6PD deficiency, sickle cell disease) to malaria has been found among Sub-Saharan Africans, which may have initially developed in 7300 BP.[99] Sub-Saharan Africans have more than 90% of the Duffy-null genotype.[115]

Pediculus
[edit]

During the Copper Age and early Islamic era of ancient Israel, West Africans may have migrated into ancient Israel and introduced head louse from West Africa.[116]

Sickle Cell
[edit]

Amid the Green Sahara, the mutation for sickle cell originated in the Sahara[104] or in the northwest forest region of western Central Africa (e.g., Cameroon)[104][117] by at least 7,300 years ago,[104][117] though possibly as early as 22,000 years ago.[118][117] The ancestral sickle cell haplotype to modern haplotypes (e.g., Cameroon/Central African Republic and Benin/Senegal haplotypes) may have first arose in the ancestors of modern West Africans, bearing haplogroups E1b1a1-L485 and E1b1a1-U175 or their ancestral haplogroup E1b1a1-M4732.[104] West Africans (e.g., Yoruba and Esan of Nigeria), bearing the Benin sickle cell haplotype, may have migrated through the northeastern region of Africa into the western region of Arabia.[104] West Africans (e.g., Mende of Sierra Leone), bearing the Senegal sickle cell haplotype,[119][104] may have migrated into Mauritania (77% modern rate of occurrence) and Senegal (100%); they may also have migrated across the Sahara, into North Africa, and from North Africa, into Southern Europe, Turkey, and a region near northern Iraq and southern Turkey.[119] Some may have migrated into and introduced the Senegal and Benin sickle cell haplotypes into Basra, Iraq, where both occur equally.[119] West Africans, bearing the Benin sickle cell haplotype, may have migrated into the northern region of Iraq (69.5%), Jordan (80%), Lebanon (73%), Oman (52.1%), and Egypt (80.8%).[119]

Schistosomes
[edit]

According to Steverding (2020), while not definite: Near the African Great Lakes, schistosomes (e.g., S. mansoni, S. haematobium) underwent evolution.[120] Subsequently, there was an expansion alongside the Nile.[120] From Egypt, the presence of schistosomes may have expanded, via migratory Yoruba people, into Western Africa.[120] Thereafter, schistosomes may have expanded, via migratory Bantu peoples, into the rest of Sub-Saharan Africa (e.g., Southern Africa, Central Africa).[120]

Thalassemia
[edit]

Through pathways taken by caravans, or via travel amid the Almovarid period, a population (e.g., Sub-Saharan West Africans) may have introduced the –29 (A → G) β-thalassemia mutation (found in notable amounts among African Americans) into the North African region of Morocco.[121]

Domesticated Animal DNA

[edit]

While the Niger-Congo migration may have been from West Africa into Kordofan, possibly from Kordofan, Sudan, Niger-Congo speakers accompanied by undomesticated helmeted guineafowls, may have traversed into West Africa, domesticated the helmeted guineafowls by 3000 BCE, and via the Bantu expansion, traversed into other parts of Sub-Saharan Africa (e.g., Central Africa, East Africa, Southern Africa).[122]

Central Africa

[edit]

Archaic Human DNA

[edit]

Archaic traits found in human fossils of West Africa (e.g., Iho Eleru fossils, which dates to 13,000 BP) and Central Africa (e.g., Ishango fossils, which dates between 25,000 BP and 20,000 BP) may have developed as a result of admixture between archaic humans and modern humans or may be evidence of late-persisting early modern humans.[80] While Denisovan and Neanderthal ancestry in non-Africans outside of Africa are more certain, archaic human ancestry in Africans is less certain and is too early to be established with certainty.[80]

Ancient DNA

[edit]

In 4000 BP, there may have been a population that traversed from Africa (e.g., West Africa or West-Central Africa), through the Strait of Gibraltar, into the Iberian Peninsula, where admixing between Africans and Iberians (e.g., of northern Portugal, of southern Spain) occurred.[123]

Cameroon
[edit]

West African hunter-gatherers, in the region of western Central Africa (e.g., Shum Laka, Cameroon), particularly between 8000 BP and 3000 BP, were found to be related to modern Central African hunter-gatherers (e.g., Baka, Bakola, Biaka, Bedzan).[124]

Democratic Republic of Congo
[edit]

At Kindoki, in the Democratic Republic of Congo, there were three individuals, dated to the protohistoric period (230 BP, 150 BP, 230 BP); one carried haplogroups E1b1a1a1d1a2 (E-CTS99, E-CTS99) and L1c3a1b, another carried haplogroup E (E-M96, E-PF1620), and the last carried haplogroups R1b1 (R-P25 1, R-M415) and L0a1b1a1.[125][126]

Y-Chromosomal DNA

[edit]

Haplogroup R1b-V88 is thought to have originated in Europe and migrated into Africa with farmers or herders in the Neolithic period, c. 5500 BC.[127][128][129][130] R1b-V88 is found at a high frequency among Chadic speaking peoples such as the Hausa,[78] as well as in Kanembu,[131] Fulani,[132] and Toubou[78] populations.

Mitochondrial DNA

[edit]

In 150,000 BP, Africans (e.g., Central Africans, East Africans) bearing haplogroup L1 diverged.[97] Between 75,000 BP and 60,000 BP, Africans bearing haplogroup L3 emerged in East Africa and eventually migrated into and became present in modern West Africans, Central Africans, and non-Africans.[97] Amid the Holocene, including the Holocene Climate Optimum in 8000 BP, Africans bearing haplogroup L2 spread within West Africa and Africans bearing haplogroup L3 spread within East Africa.[97] As the largest migration since the Out of Africa migration, migration from Sub-Saharan Africa toward the North Africa occurred, by West Africans, Central Africans, and East Africans, resulting in migrations into Europe and Asia; consequently, Sub-Saharan African mitochondrial DNA was introduced into Europe and Asia.[97]

Mitochondrial haplogroup L1c is strongly associated with pygmies, especially with Bambenga groups.[133] L1c prevalence was variously reported as: 100% in Ba-Kola, 97% in Aka (Ba-Benzélé), and 77% in Biaka,[134] 100% of the Bedzan (Tikar), 97% and 100% in the Baka people of Gabon and Cameroon, respectively,[135] 97% in Bakoya (97%), and 82% in Ba-Bongo.[133] Mitochondrial haplogroups L2a and L0a are prevalent among the Bambuti.[133][136]

Autosomal DNA

[edit]

Genetically, African pygmies have some key difference between them and Bantu peoples.[137][138]

Medical DNA

[edit]

Evidence suggests that, when compared to other Sub-Saharan African populations, African pygmy populations display unusually low levels of expression of the genes encoding for human growth hormone and its receptor associated with low serum levels of insulin-like growth factor-1 and short stature.[139]

The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[99] Throughout Sub-Saharan Africa, genetic adaptation (e.g., rs334 mutation, Duffy blood group, increased rates of G6PD deficiency, sickle cell disease) to malaria has been found among Sub-Saharan Africans, which may have initially developed in 7300 BP.[99] Sub-Saharan Africans have more than 90% of the Duffy-null genotype.[115] In the rainforests of Central Africa, genetic adaptation for non-height-related factors (e.g., immune traits, reproduction, thyroid function) and short stature (e.g., EHB1 and PRDM5 – bone synthesis; OBSCN and COX10 – muscular development; HESX1 and ASB14 – pituitary gland's growth hormone production/secretion) has been found among rainforest hunter-gatherers.[99]

Eastern Africa

[edit]

From the region of Kenya and Tanzania to South Africa, eastern Bantu-speaking Africans constitute a north to south genetic cline; additionally, from eastern Africa to toward southern Africa, evidence of genetic homogeneity is indicative of a serial founder effect and admixture events having occurred between Bantu-speaking Africans and other African populations by the time the Bantu migration had spanned into South Africa.[99]

Archaic Human DNA

[edit]

While Denisovan and Neanderthal ancestry in non-Africans outside of Africa are more certain, archaic human ancestry in Africans is less certain and is too early to be established with certainty.[80]

Ancient DNA

[edit]
Ethiopia
[edit]

At Mota, in Ethiopia, an individual, estimated to date to the 5th millennium BP, carried haplogroups E1b1 and L3x2a.[140][141] The individual of Mota is genetically related to groups residing near the region of Mota, and in particular, are considerably genetically related to the Aari people, especially the blacksmith caste of that group.[142][143]

Kenya
[edit]

At Jawuoyo Rockshelter, in Kisumu County, Kenya, a forager of the Later Stone Age carried haplogroups E1b1b1a1b2/E-V22 and L4b2a2c.[144][145]

At Ol Kalou, in Nyandarua County, Kenya, a pastoralist of the Pastoral Neolithic carried haplogroups E1b1b1b2b2a1/E-M293 and L3d1d.[144][145]

At Kokurmatakore, in Marsabit County, Kenya, a pastoralist of the Pastoral Iron Age carried haplogroups E1b1b1/E-M35 and L3a2a.[144][145]

At White Rock Point, in Homa Bay County, Kenya, there were two foragers of the Later Stone Age; one carried haplogroups BT (xCT), likely B, and L2a4, and another probably carried haplogroup L0a2.[144][145]

At Nyarindi Rockshelter, in Kenya, there were two individuals, dated to the Later Stone Age (3500 BP); one carried haplogroup L4b2a and another carried haplogroup E (E-M96, E-P162).[125][126]

At Lukenya Hill, in Kenya, there were two individuals, dated to the Pastoral Neolithic (3500 BP); one carried haplogroups E1b1b1b2b (E-M293, E-CTS10880) and L4b2a2b, and another carried haplogroup L0f1.[125][126]

At Hyrax Hill, in Kenya, an individual, dated to the Pastoral Neolithic (2300 BP), carried haplogroups E1b1b1b2b (E-M293, E-M293) and L5a1b.[125][126]

At Molo Cave, in Kenya, there were two individuals, dated to the Pastoral Neolithic (1500 BP); while one had haplogroups that went undetermined, another carried haplogroups E1b1b1b2b (E-M293, E-M293) and L3h1a2a1.[125][126]

At Kakapel, in Kenya, there were three individuals, one dated to the Later Stone Age (3900 BP) and two dated to the Later Iron Age (300 BP, 900 BP); one carried haplogroups CT (CT-M168, CT-M5695) and L3i1, another carried haplogroup L2a1f, and the last carried haplogroup L2a5.[125][126]

At Panga ya Saidi, in Kenya, an individual, estimated to date between 496 BP and 322 BP, carried haplogroups E1b1b1b2 and L4b2a2.[146]

At Kilifi, Mtwapa, in Kenya, an individual, dated between 1250 CE and 1650 CE, carried haplogroup L3b1a1a.[147]

Tanzania
[edit]

At Mlambalasi rockshelter, in Tanzania, an individual, dated between 20,345 BP and 17,025 BP, carried undetermined haplogroups.[148]

At Gishimangeda Cave, in Karatu District, Tanzania, there were eleven pastoralists of the Pastoral Neolithic; one carried haplogroups E1b1b1a1b2/E-V22 and HV1b1, another carried haplogroup L0a, another carried haplogroup L3x1, another carried haplogroup L4b2a2b, another carried haplogroups E1b1b1b2b2a1/E-M293 and L3i2, another carried haplogroup L3h1a2a1, another carried haplogroups E1b1b1b2b2/E-V1486, likely E-M293 and L0f2a1, and another carried haplogroups E1b1b1b2b2/E-V1486, likely E-M293, and T2+150; while most of the haplogroups among three pastoralists went undetermined, one was determined to carry haplogroup BT, likely B.[144][145]

At Kilwa, Coast, in Tanzania, an individual, dated between 1300 CE and 1600 CE, carried haplogroups J2a2a1a1a2a~ and L2a1h.[147]

At Lindi, in Tanzania, an individual, dated between 1511 cal CE and 1664 cal CE, carried haplogroups E1b1a1a1a2a1a3a1d~ and L0a1a2.[147]

At Makangale Cave, on Pemba Island, Tanzania, an individual, estimated to date between 1421 BP and 1307 BP, carried haplogroup L0a.[146]

At Songo Mnara, in Tanzania, an individual, dated between 1294 cal CE and 1392 cal CE, carried haplogroups R1a and L3e3a.[147]

Uganda
[edit]

At Munsa, in Uganda, an individual, dated to the Later Iron Age (500 BP), carried haplogroup L3b1a1.[125][126]

Y-Chromosomal DNA

[edit]

As of 19,000 years ago, Africans, bearing haplogroup E1b1a-V38, likely traversed across the Sahara, from east to west.[104]

Before the slave trade period, East Africans, who carried haplogroup E1b1a-M2, expanded into Arabia, resulting in various rates of inheritance throughout Arabia (e.g., 2.8% Qatar, 3.2% Yemen, 5.5% United Arab Emirates, 7.4% Oman).[149]

Mitochondrial DNA

[edit]

In 150,000 BP, Africans (e.g., Central Africans, East Africans) bearing haplogroup L1 diverged.[97] In 130,000 BP, Africans bearing haplogroup L5 diverged in East Africa.[97] Between 130,000 BP and 75,000 BP, behavioral modernity emerged among Southern Africans and long-term interactions between the regions of Southern Africa and Eastern Africa became established.[97] Between 75,000 BP and 60,000 BP, Africans bearing haplogroup L3 emerged in East Africa and eventually migrated into and became present in modern West Africans, Central Africans, and non-Africans.[97] Amid the Holocene, including the Holocene Climate Optimum in 8000 BP, Africans bearing haplogroup L2 spread within West Africa and Africans bearing haplogroup L3 spread within East Africa.[97] As the largest migration since the Out of Africa migration, migration from Sub-Saharan Africa toward the North Africa occurred, by West Africans, Central Africans, and East Africans, resulting in migrations into Europe and Asia; consequently, Sub-Saharan African mitochondrial DNA was introduced into Europe and Asia.[97] During the early period of the Holocene, 50% of Sub-Saharan African mitochondrial DNA was introduced into North Africa by West Africans and the other 50% was introduced by East Africans.[97] During the modern period, a greater number of West Africans introduced Sub-Saharan African mitochondrial DNA into North Africa than East Africans.[97] Between 15,000 BP and 7000 BP, 86% of Sub-Saharan African mitochondrial DNA was introduced into Southwest Asia by East Africans, largely in the region of Arabia, which constitute 50% of Sub-Saharan African mitochondrial DNA in modern Southwest Asia.[97] In the modern period, 68% of Sub-Saharan African mitochondrial DNA was introduced by East Africans and 22% was introduced by West Africans, which constitutes 50% of Sub-Saharan African mitochondrial DNA in modern Southwest Asia.[97]

Autosomal DNA

[edit]

Across all areas of Madagascar, the average ancestry for the Malagasy people was found to be 4% West Eurasian, 37% Austronesian, and 59% Bantu.[67]

Medical DNA

[edit]

The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[99] Throughout Sub-Saharan Africa, genetic adaptation (e.g., rs334 mutation, Duffy blood group, increased rates of G6PD deficiency, sickle cell disease) to malaria has been found among Sub-Saharan Africans, which may have initially developed in 7300 BP.[99] Sub-Saharan Africans have more than 90% of the Duffy-null genotype.[115] In the highlands of Ethiopia, genetic adaptation (e.g., rs10803083, an SNP associated with the rate and function of hemoglobin; BHLHE41, a gene associated with circadian rhythm and hypoxia response; EGNL1, a gene strongly associated with oxygen homeostasis in mammals) to hypoxia and low atmospheric pressure has been found among the Amhara people, which may have developed within the past 5000 years.[99] In Tanzania, genetic adaptation (e.g., greater amount of amylase genes than in African populations that consume low-starch foods) has been found in the Hadza people due to a food diet that especially includes consumption of tubers.[99]

Southern Africa

[edit]

From the region of Kenya and Tanzania to South Africa, eastern Bantu-speaking Africans constitute a north to south genetic cline; additionally, from eastern Africa to toward southern Africa, evidence of genetic homogeneity is indicative of a serial founder effect and admixture events having occurred between Bantu-speaking Africans and other African populations by the time the Bantu migration had spanned into South Africa.[99]

Archaic Human DNA

[edit]

While Denisovan and Neanderthal ancestry in non-Africans outside of Africa are more certain, archaic human ancestry in Africans is less certain and is too early to be established with certainty.[80]

Ancient DNA

[edit]

Three Later Stone Age hunter-gatherers carried ancient DNA similar to Khoisan-speaking hunter-gatherers.[150] Prior to the Bantu migration into the region, as evidenced by ancient DNA from Botswana, East African herders migrated into Southern Africa.[150] Out of four Iron Age Bantu agriculturalists of West African origin, two earlier agriculturalists carried ancient DNA similar to Tsonga and Venda peoples and the two later agriculturalists carried ancient DNA similar to Nguni people; this indicates that there were various movements of peoples in the overall Bantu migration, which resulted in increased interaction and admixing between Bantu-speaking peoples and Khoisan-speaking peoples.[150]

Botswana
[edit]

At Nqoma, in Botswana, an individual, dated to the Early Iron Age (900 BP), carried haplogroup L2a1f.[125][126]

At Taukome, in Botswana, an individual, dated to the Early Iron Age (1100 BP), carried haplogroups E1b1a1 (E-M2, E-Z1123) and L0d3b1.[125][126]

At Xaro, in Botswana, there were two individuals, dated to the Early Iron Age (1400 BP); one carried haplogroups E1b1a1a1c1a and L3e1a2, and another carried haplogroups E1b1b1b2b (E-M293, E-CTS10880) and L0k1a2.[125][126]

Malawi
[edit]

At Fingira rockshelter, in Malawi, an individual, dated between 6179 BP and 2341 BP, carried haplogroups B2 and L0d1.[148]

At Chencherere, in Malawi, an individual, estimated to date between 5400 BP and 4800 BP, carried haplogroup L0k2.[146]

At Hora 1 rockshelter, in Malawi, an individual, dated between 16,897 BP and 15,827 BP, carried haplogroups B2b and L5b.[148]

South Africa
[edit]

At Doonside, in South Africa, an individual, estimated to date between 2296 BP and 1910 BP, carried haplogroup L0d2.[151][152]

At Ballito Bay, South Africa, an individual, estimated to date between 1986 BP and 1831 BP, carried haplogroups A1b1b2 and L0d2c1.[151][152]

At Kalemba rockshelter, in Zambia, an individual, dated between 5285 BP and 4975 BP, carried haplogroup L0d1b2b.[148]

Y-Chromosomal DNA

[edit]
Distribution of Y-Chromosome Haplogroup A in Africa.
Distribution of haplogroup B (M60) of the human Y chromosome in native populations.

Various Y chromosome studies show that the San carry some of the most divergent (oldest) human Y-chromosome haplogroups. These haplogroups are specific sub-groups of haplogroups A and B, the two earliest branches on the human Y-chromosome tree.[153][154][155]

Mitochondrial DNA

[edit]

In 200,000 BP, Africans (e.g., Khoisan of Southern Africa) bearing haplogroup L0 diverged from other Africans bearing haplogroup L1′6, which tend to be northward of Southern Africa.[97] Between 130,000 BP and 75,000 BP, behavioral modernity emerged among Southern Africans and long-term interactions between the regions of Southern Africa and Eastern Africa became established.[97]

Mitochondrial DNA studies also provide evidence that the San carry high frequencies of the earliest haplogroup branches in the human mitochondrial DNA tree. This DNA is inherited only from one's mother. The most divergent (oldest) mitochondrial haplogroup, L0d, has been identified at its highest frequencies in the southern African San groups.[153][156][157][158]

Autosomal DNA

[edit]

Henn et al. (2011) found that the ǂKhomani San, as well as the Sandawe and Hadza peoples of Tanzania, were the most genetically diverse of any living humans studied. This high degree of genetic diversity hints at the origin of anatomically modern humans.[159][160]

Medical DNA

[edit]

Among the ancient DNA from three hunter-gatherers sharing genetic similarity with San people and four Iron Age agriculturalists, their SNPs indicated that they bore variants for resistance against sleeping sickness and Plasmodium vivax.[161] In particular, two out of the four Iron Age agriculturalists bore variants for resistance against sleeping sickness and three out of the four Iron Age agriculturalists bore Duffy negative variants for resistance against malaria.[161] In contrast to the Iron Age agriculturalists, from among the San-related hunter-gatherers, a six-year-old boy may have died from schistosomiasis.[161] In Botswana, a man, who dates to 1400 BP, may have also carried the Duffy negative variant for resistance against malaria.[161]

The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[99] Throughout Sub-Saharan Africa, genetic adaptation (e.g., rs334 mutation, Duffy blood group, increased rates of G6PD deficiency, sickle cell disease) to malaria has been found among Sub-Saharan Africans, which may have initially developed in 7300 BP.[99] Sub-Saharan Africans have more than 90% of the Duffy-null genotype.[115] In the Kalahari Desert region of Africa, various possible genetic adaptations (e.g., adiponectin, body mass index, metabolism) have been found among the ǂKhomani people.[99] Sub-Saharan Africans have more than 90% of the Duffy-null genotype.[115] In South Africa, genetic adaptation (e.g., rs28647531 on chromosome 4q22) and strong susceptibility to tuberculosis has been found among Coloureds.[99]

Recent African origin of modern humans

[edit]

Between 500,000 BP and 300,000 BP, anatomically modern humans may have emerged in Africa.[162] As Africans (e.g., Y-Chromosomal Adam, Mitochondrial Eve) have migrated from their places of origin in Africa to other locations in Africa, and as the time of divergence for East African, Central African, and West African lineages are similar to the time of divergence for the Southern African lineage, there is insufficient evidence to identify a specific region for the origin of humans in Africa.[80] In 100,000 BP, anatomically modern humans migrated from Africa into Eurasia.[163] Subsequently, tens of thousands of years after, the ancestors of all present-day Eurasians migrated from Africa into Eurasia and eventually became admixed with Denisovans and Neanderthals.[163]

Archaeological and fossil evidence provide support for the African origin of homo sapiens and behavioral modernity.[164] Models reflecting a pan-African origin (multiple locations of origin within Africa) and evolution of modern humans have been developed.[164] As the idea of "modern" has become increasingly problematized, research has "begun to disentangle what is meant by "modern" genetic ancestry, skeletal morphology, and behavior, recognizing these are unlikely to form a single package."[164]

In comparison to the non-African genome, the African genome features a ~25% greater number of polymorphisms,[99] or 3 to 5 times as many,[115] and genetic variants that are rare outside of Africa are found to occur at an abundant rate within Africa.[99] Most of the genetic diversity found among non-Africans is found to be, at large, a subset of genetic diversity found among Africans.[99] The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[99] Throughout Sub-Saharan Africa, genetic adaptation (e.g., rs334 mutation, Duffy blood group, increased rates of G6PD deficiency, sickle cell disease) to malaria has been found among Sub-Saharan Africans, which may have initially developed in 7300 BP.[99] Throughout Africa, various genetic adaptations (e.g., apolipoprotein L1 (APOL1): G1 and G2 haplotype resistance to trypanosomiasis and increased risk of kidney disease; human leukocyte antigen (HLA) genes; major histocompatibility complex (MHC)) to HIV-1, smallpox, trypanosomiasis (African sleeping sickness), and tuberculosis has been found among Africans.[99] Biomedical tests for specific genetic variants (e.g., rs1799853 in the CYP2C9 gene), which have been approved by the U.S. Food and Drug Administration and are intended to indicate correct prescription of warfarin, has been found to be increasingly irrelevant to Africans as the variants are rare in Africa.[99] As frequency rate factors into considering and deciding variant pathogenicity and generalizable polygenic scores, modern clinical classifications of genetic variant pathogenicity are found to be inadequate due to a lack of genetic diversity in biomedical studies.[99] Fan et al (2023) recently found ~5.3 million unique genetic variants in 180 African hunter-gatherer populations, and among existing classifications for variants determined to likely be "pathogenic", ~29% (44/154) of these "pathogenic" classified variants were found to occur frequently among the African hunter-gatherers.[99]

See also

[edit]

Notes

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
The genetic history of Africa encompasses the evolutionary origins of anatomically modern humans (Homo sapiens), who first appeared on the continent approximately 300,000 years ago, as evidenced by and genomic data from sites in East and . This history is characterized by Africa's unparalleled human , with effective sizes estimated at around 15,000 individuals compared to about 7,500 in non-African groups, reflecting deep ancestral lineages and limited bottlenecks during early expansions. Recent genomic analyses as of 2025 further reveal deep ancestral structure shared by all modern humans, involving splits and admixtures around 500,000–300,000 years ago, primarily in . Key events include the Out-of-Africa migration between 50,000 and 80,000 years ago, which dispersed modern humans to via routes through the or the , and subsequent back-migrations that introduced non-African ancestry into North and East African populations. Intra-continental dynamics further shaped this genetic landscape, with major migrations such as the originating from the Nigeria- region around 5,000 years ago, spreading Niger-Congo languages, agriculture, and genetic signatures across Central, Eastern, and through admixture with local forager groups like the . Similarly, Nilo-Saharan pastoralist movements from approximately 10,500 years ago influenced West and East African populations, while Eurasian gene flow into Northeast Africa, dated to about 3,000 years ago, is linked to the spread of and . from sites like Shum Laka in (8,000–3,000 years ago) and in (2,000 years ago) has revealed at least four deeply diverged ancestral lineages dating back 200,000–300,000 years, underscoring Africa's role as the and highlighting gene flow among early populations; 2025 from the Green Sahara has identified an additional deeply divergent North African lineage. Selective pressures from diverse environments have driven notable adaptations, including mutations for in East African pastoralists evolving 3,000–7,000 years ago in response to dairy consumption, and variants like the sickle-cell allele (HbS) and G6PD deficiencies selected for resistance across sub-Saharan regions. North African populations exhibit a complex mosaic, with genomic evidence of at least five ancestral components, including back-to-Africa migrations from the and around 7,000–5,000 years ago, contributing to isolation periods and recent admixtures. Whole-genome sequencing of indigenous groups, such as the 44 populations analyzed in a 2019 study, confirms geographic and linguistic correlations in ancestry clusters, with basal lineages like the San diverging around 160,000 years ago. These findings, informed by advances in ancient and modern , continue to illuminate Africa's profound influence on global and the implications for disease susceptibility and phenotypic variation.

Overview

Origins and Diversity of African Populations

Africa is widely recognized as the cradle of Homo sapiens, with the earliest known fossils dating to approximately 300,000 years ago at sites such as in , and around 233,000 years ago at Omo Kibish in Ethiopia's East African Rift Valley. These discoveries, corroborated by genetic analyses of modern and , indicate that anatomically modern humans emerged through a pan-African process involving multiple regional populations rather than a single localized origin. Fossil evidence from diverse African regions, including East, North, and , supports this model of early within the continent. African populations exhibit the highest levels of observed among s globally, a pattern particularly pronounced in sub-Saharan groups. This elevated variation stems from Africa's status as the long-term evolutionary homeland of Homo sapiens, allowing for extended accumulation of genetic mutations and adaptations over hundreds of thousands of years. In contrast, non-African populations descend from a subset of this ancestral diversity following later dispersals, resulting in comparatively lower heterozygosity outside the continent. Studies of genome-wide data confirm that sub-Saharan Africans harbor more unique alleles and deeper lineage splits than Eurasian or other groups, underscoring the continent's role in shaping genetic foundations. Indigenous African lineages form the basal branches of the human , with (mtDNA) haplogroups L0 through L6 representing the root clades exclusive to African populations. These haplogroups, diverging over 100,000–200,000 years ago, encapsulate the earliest maternal ancestries and predate all non-African mtDNA lineages. Similarly, Y-chromosomal haplogroups A and B constitute the deepest branches on the paternal tree, originating in and carried predominantly by indigenous groups such as the . These basal markers highlight how African genetic anchors the global human , with all other haplogroups deriving from derived African subclades. Africa's varied geography, including expansive barriers like the Desert and dense tropical rainforests, significantly influenced early population structuring and genetic differentiation. The acted as a formidable divide between northern and sub-Saharan groups during periods of aridity, limiting and fostering isolated evolutionary trajectories. Rainforests in similarly compartmentalized populations, promoting localized adaptations and contributing to the mosaic of genetic clusters observed today. This interplay of isolation and occasional connectivity shaped the foundational diversity from which subsequent dispersals, such as the Out-of-Africa event around 60,000–70,000 years ago, emerged.

Out-of-Africa Migration

The Out-of-Africa (OOA) migration refers to the primary dispersal of anatomically modern humans (Homo sapiens) from to , supported by genetic evidence showing that non-African populations derive from a subset of African genetic diversity. (mtDNA) analyses reveal that all non-African mtDNA lineages trace back to , which originated in approximately 70,000–60,000 years ago, indicating a common ancestral pool for Eurasian populations. Autosomal DNA studies further confirm reduced heterozygosity and allelic diversity outside , consistent with a where migrating groups carried only a fraction of the ancestral variation present in African populations. Y-chromosomal data similarly show non-African haplogroups C and F descending from African roots, reinforcing the unidirectional outflow model. Genetic timelines place limited initial dispersals around 120,000 years ago, based on and sparse genetic traces, but the major successful expansion occurred approximately 70,000–50,000 years ago, as estimated from calibrations of mtDNA and whole-genome sequences. This primary wave is marked by the rapid diversification of L3-derived haplogroups and in South Asia shortly after exit, suggesting a swift colonization following the Toba supervolcano eruption around 74,000 years ago that may have influenced migration dynamics. Later back-migrations from partially reversed this pattern by introducing non-L3 lineages into African genomes. Two primary routes facilitated the OOA dispersal: a southern coastal pathway across the Bab el-Mandeb Strait from the to the , evidenced by high frequencies of basal M and N lineages in South Asian and Australasian populations; and a northern inland route via the and , supported by Y-chromosomal distributions and genome-wide admixture patterns in Near Eastern groups. Haplogroup L3's subclades provide key phylogenetic markers, with M predominating in southern route descendants and N in northern ones, highlighting how environmental opportunities like lowered sea levels during glacial periods enabled these pathways. The OOA event involved severe bottlenecks due to serial founder effects, where successive small groups colonized , drastically reducing effective population sizes to 1,000–2,500 breeding individuals during the initial exit around 60,000 years ago. analyses of single polymorphisms (SNPs) estimate this reduction persisted for millennia, leading to a 5- to 10-fold loss in compared to African ancestors, whose effective size remained stable at around 14,000. This demographic constriction explains the star-like phylogeny of non-African haplogroups and elevated in Eurasian genomes.

Eurasian Back-Migrations and Gene Flow

Following the Out-of-Africa migration, multiple waves of gene flow from back into introduced significant non-African ancestry components, shaping the genetic landscape of various African populations. These back-migrations occurred through diverse mechanisms, including , , and , and were unevenly distributed, with the highest impacts observed in North and East compared to West and Central regions. Key episodes include the influx of Neolithic farmers approximately 8,000 years ago, primarily affecting via maritime routes from Iberia and the , where early agriculturalists carried ancestry related to populations. Subsequent pastoralist migrations around 3,000–5,000 years ago introduced additional Eurasian elements into East and , likely mediated by mobile herding communities expanding from the . Later, Arab expansions beginning about 1,400 years ago, during the Islamic conquests starting in the CE, brought further , particularly to and through tribal migrations from the . These events left detectable genetic signatures in the form of Eurasian-derived s, such as lineages H and U, and Y-chromosomal J, which entered via these migratory processes. Autosomal analyses confirm that these s reflect admixture events rather than independent origins within . Admixture levels vary regionally, reaching up to 20–30% Eurasian ancestry in North African populations, while sub-Saharan groups generally exhibit lower proportions, often below 10%, though some East African communities show elevated levels up to 40–50%. The genetic patterns correlate with cultural shifts, as Neolithic back-migrations facilitated the spread of farming practices across the , pastoralist flows promoted herding economies in eastern and southern savannas, and influences disseminated alongside trans-Saharan trade networks, amplifying gene flow in coastal and Sahelian zones. These dynamics underscore how demographic movements intertwined with technological and religious innovations to influence Africa's .

Evolutionary Foundations

Recent African Origin of Modern Humans

The Recent Origin (RAO) model, also known as the Out-of-Africa model, posits that anatomically modern humans (Homo sapiens) originated in through the evolution of earlier hominins, such as , around 200,000 to 300,000 years ago, with subsequent dispersal to other continents leading to the replacement or partial assimilation of archaic human populations outside . This framework emerged prominently in the late from analyses of (mtDNA), which revealed that all modern human mtDNA lineages trace back to a common African , often termed "," dated to approximately 150,000–200,000 years ago based on estimates. The model contrasts with earlier views by emphasizing a recent, singular origin in rather than across multiple regions, supported by both fossil and genetic data indicating that non-African populations represent a subset of African with reduced variation due to founder effects during migrations. Fossil evidence provides critical chronological support for the RAO model, with the oldest known Homo sapiens remains discovered at Jebel Irhoud in Morocco, dated to approximately 315,000 years ago through thermoluminescence and electron spin resonance methods applied to associated stone tools and sediments. These fossils, including a partial skull and jaw, exhibit a mix of modern facial features and more archaic braincase morphology, suggesting an early stage in the emergence of H. sapiens across Africa rather than a single localized event. Similarly, the Omo Kibish site in Ethiopia yielded the Omo I partial skeleton, recently redated to at least 233,000 years ago using volcanic ash layers and argon-argon dating, confirming it as one of the earliest unequivocally modern H. sapiens specimens with fully modern skeletal proportions and cranial traits. These African finds, spanning North and East Africa, indicate a pan-African process of modernization, where H. sapiens likely replaced or interbred with local archaic forms like H. heidelbergensis, establishing the species' dominance by around 200,000 years ago. Genetic studies reinforce the African origin by demonstrating deep divergence times among basal African lineages, which predate those in non-African populations and reflect the highest levels of genetic diversity on the continent. For instance, whole-genome sequencing of ancient southern African individuals from sites like Ballito Bay (dated ~2,000 years ago) estimates the initial split among modern populations at 350,000–260,000 years ago, with Khoe-San groups preserving the most divergent lineages that branch earliest in the phylogeny. Autosomal DNA analyses further show that non-African genomes form a nested within African variation, with effective sizes in Africa remaining larger and more stable, consistent with an origin and expansion from the continent without significant contributions from Eurasian archaic humans at the species' inception. These patterns, observed across mtDNA haplogroups L0–L3 (basal to all lineages) and Y-chromosomal equivalents, underscore Africa's role as the cradle of H. sapiens, with genetic bottlenecks during out-migrations explaining the shallower diversity elsewhere. The RAO model resolved long-standing debates between the "replacement" hypothesis—favoring complete displacement of archaic humans by African emigrants—and the "multiregional" hypothesis, which proposed continuous and parallel evolution across continents from descendants. By the early 2000s, accumulating , archaeological, and genomic evidence had largely discredited strict multiregionalism, affirming an African-centric origin with limited archaic (such as minor contributions from Neanderthals outside or unidentified "ghost" lineages within ) that did not alter the primary African ancestry of modern humans. This consensus, often termed the Recent African Origin with Hybridization (RAOH) model, integrates evidence of small-scale interbreeding while maintaining that over 95% of modern human ancestry derives from African H. sapiens populations that emerged and diversified on the continent.

Archaic Admixtures in African Genomes

Genomic studies have revealed that modern human populations in carry traces of introgression from archaic hominins, indicating interbreeding events that occurred after the emergence of anatomically modern humans on the continent. This archaic admixture parallels the well-documented and contributions to non-African genomes but involves previously unknown "ghost" lineages within , suggesting a more complex evolutionary than previously assumed. Evidence for archaic introgression is particularly prominent in West and Central African populations, where analyses estimate that 2% to 19% of genetic ancestry derives from an extinct hominin species. For instance, in West African groups such as the Yoruba, Esan, Mende, and Gambians, this ghost archaic contribution accounts for segments showing elevated divergence from modern human sequences, with an average of about 6-7% across sampled individuals. In Central African hunter-gatherers like the Biaka Pygmies and San, earlier work identified roughly 2% archaic DNA, likely from a similar deep-diverging lineage. These findings indicate that archaic introgression has substantially shaped the genetic diversity of present-day Africans, with the ghost population estimated to have split from the modern human lineage between 360,000 and 1.02 million years ago. Specific cases of admixture involve unknown archaic species, potentially including candidates like or other undiscovered hominins, with interbreeding events dated to approximately 40,000 to 200,000 years ago. In the West African study, the admixture timing is inferred to be around 43,000 years ago on average, though the range extends up to 124,000 years, detected through genome-wide mapping of introgressed segments that persist at high frequency, possibly due to adaptive advantages. These events challenge the traditional view of an "Out-of-Africa" migration from a genetically pure modern human population, as the introgressed archaic DNA in African genomes implies that early migrants may have carried such ancestry, contributing to Eurasian Neanderthal signals indirectly. Detection of these archaic signals relies on advanced computational methods that identify non-modern human haplotypes and quantify their contributions. Key approaches include the S* statistic, which scans for unusually divergent haplotype lengths indicative of archaic origin, as applied to Pygmy and San genomes to reveal excess archaic alleles. Complementarily, f4 statistics measure allele sharing imbalances across populations, showing significant excess archaic ancestry when comparing African groups to outgroups like Eurasians. Additional techniques, such as conditional site frequency spectra and approximate Bayesian computation, refine estimates of admixture proportions and timings by modeling the decay of linkage disequilibrium in introgressed segments. These methods have progressively uncovered higher levels of archaic influence in Africa than initially anticipated, emphasizing the role of ghost lineages in human evolution.

Core Genetic Lineages

Mitochondrial DNA Haplogroups

(mtDNA) haplogroups L0 through L6 form the foundational root of the human mtDNA , encompassing all basal lineages of modern human maternal ancestry and originating exclusively within . These haplogroups represent the earliest branches, with L0 as the most ancient, diverging from the root around 140,000–210,000 years before present (ybp), followed by splits leading to L1, L2, L3, and the rarer L4, L5, and L6. The entire phylogeny coalesces to a common ancestral mtDNA sequence in approximately 150,000–200,000 ybp, marking the origin of modern human matrilineal diversity. The root of the mtDNA tree is firmly placed in , where the earliest diversification occurred among ancient populations, with subsequent expansions shaping continental distributions. , emerging around 61,000–86,000 ybp, serves as the critical precursor to the non-African macrohaplogroups and , which arose from its subclades and facilitated the out-of-Africa migrations approximately 50,000–65,000 ybp. Basal L haplogroups like L0 and L1 exhibit coalescence times exceeding 100,000 years, with L0 dated to 124,000–172,000 ybp and L1 to 87,000–139,000 ybp, reflecting deep-time persistence in African populations. Africa harbors the highest levels of mtDNA genetic variation globally, underscoring its role as the cradle of human maternal lineages, with nucleotide diversity metrics significantly elevated compared to non-African regions due to the antiquity and breadth of L haplogroups. This diversity is particularly pronounced in sub-Saharan populations, where ancient branches have accumulated mutations over millennia without the bottlenecks experienced elsewhere. Among major African haplogroups, L0 and L1 predominate in southern African Khoisan-speaking groups, comprising up to 70–80% of their mtDNA pools and representing some of the oldest surviving lineages with minimal external admixture. In contrast, L2 and L3 are more prevalent in West and East African populations, with L2 accounting for about 25% of sub-Saharan haplotypes and showing widespread distribution linked to early expansions from western sources around 73,000–127,000 ybp. L3, beyond its role in Eurasian dispersal, remains common in , often exceeding 20–30% in Ethiopian and Kenyan groups. Specific subclades highlight regional dynamics: L1b is enriched in Central African Pygmy populations, where it reaches frequencies of 20–40% and traces to autochthonous lineages predating major migrations. Similarly, L3f subclades, including L3f1 and L3f3, expanded during the Bantu migrations starting around 3,000–4,000 ybp, carrying diverse L3 lineages into Central and and contributing to up to 15–25% of mtDNA in Bantu-speaking communities today. These patterns illustrate how mtDNA haplogroups have tracked maternal population movements across the continent while preserving ancient African roots.

Y-Chromosomal Haplogroups

Y-chromosomal haplogroups, which trace paternal lineages through the non-recombining portion of the , provide key insights into the male-mediated dispersals and expansions within Africa's diverse populations. The human Y-chromosome phylogeny is rooted in Africa, with the most basal lineages exhibiting high diversity among indigenous groups such as the and Pygmies. These haplogroups reveal ancient divergences and more recent demographic events tied to migrations, including the spread of farming and . The deepest branches of the Y-chromosome tree, including s A00 through A3, are predominantly found in , particularly among populations in and Pygmy groups in . For instance, A00, identified in individuals from , represents an extremely ancient root, with an estimated time to (TMRCA) of approximately 275,000 years ago, underscoring 's role as the origin of modern paternal lineages. A lineages, such as A2 and A3b1, are frequent in speakers (up to 47.7% in some groups), reflecting their isolation and deep ancestry. Upstream of the non-African branches, serves as a critical node, splitting into B (endemic to Africa) and CT (which includes the DE clade associated with Out-of-Africa migrations). is widespread in central and eastern Africa, reaching frequencies of about 48.9% in Pygmy populations and 10.3% across sub-Saharan groups, with subclades like B2a common among East Africans and Bantu speakers. This distribution highlights B's persistence among forager communities, contrasting with the maternal lineages traced by haplogroups, which show complementary patterns in these same populations. The major expansions within Africa are dominated by subclades of haplogroup E, which arose from an African root around 50,000–70,000 years ago. Haplogroup E1b1a (E-M2) underwent a star-like expansion linked to the Bantu migrations, originating in West-Central Africa approximately 5,800 years ago and spreading southward, now comprising a significant portion of male lineages in Bantu-speaking groups across . Similarly, E1b1b (E-M215), with key subclades like E-M35 and E-M293, is prevalent in North and , associated with pastoralist dispersals from the into southern regions around 2,000–3,000 years ago, facilitating the introduction of herding practices. The overall Y-chromosome phylogeny places the root of all modern human male lineages in , with a TMRCA estimated at 200,000–300,000 years ago based on deep sequencing of basal clades. The DE branch, which includes non-African lineages like those in Eurasians, diverged early as part of the Out-of-Africa event around 50,000–70,000 years ago, while remaining African diversity expanded within the continent. Many African haplogroups exhibit star-like structures indicative of rapid growth bursts between 5,000 and 10,000 years ago, coinciding with the transition to and in regions like the and Valley.

Autosomal DNA and Population Structure

Autosomal DNA studies, which examine the entire non-sex genome, provide a comprehensive view of African population structure by integrating signals from all genetic loci, revealing patterns of divergence, admixture, and diversity that complement uniparental markers like and Y-chromosomes. These analyses highlight Africa's role as the cradle of , with sub-Saharan populations exhibiting the highest levels of genome-wide diversity due to long-term continuity and complex internal migrations. Genome-wide () data from diverse African groups have been instrumental in mapping this , often using methods like (PCA) to visualize relationships among populations. Principal component analysis of autosomal SNPs consistently identifies distinct genetic clusters corresponding to major African ethno-linguistic groups, including (click-speaking foragers), Niger-Congo speakers (prevalent in West and ), Nilo-Saharan groups (common in ), and Afroasiatic populations (found in North and ). For instance, a seminal study of over 1,300 individuals from 121 African populations showed that the first principal component separates groups from other Africans, while subsequent components delineate Niger-Congo, Nilo-Saharan, and Afroasiatic clusters, reflecting ancient divergences estimated at 20,000–100,000 years ago. More recent whole-genome sequencing of 426 individuals from 50 diverse African ethnicities reinforced these findings, with PCA plots displaying clear separation along linguistic lines and highlighting fine-scale structure within regions like . These clusters underscore the deep genetic substructure within , driven by geographic isolation and historical expansions rather than recent admixture alone. Admixture modeling using f3 and f4 statistics has quantified extensive within , particularly from major migrations like the . The f3 statistic tests for admixture by measuring excess shared drift between two populations in a third, while f4 ratios detect directional ; negative f3 values and significant f4 deviations indicate admixture events. For example, analyses of southern African genomes revealed that Bantu-speaking groups admixed with local and Pygmy populations around 1,200–1,800 years ago, with f4 statistics showing up to 20–30% ancestry in some Bantu groups. A 2023 study of 44 Bantu-speaking populations across used these statistics to confirm region-specific admixture, such as elevated East African pastoralist into southern Bantu groups, illustrating how internal migrations shaped modern autosomal profiles without Eurasian input. Effective population sizes (Ne) inferred from autosomal data demonstrate Africa's greater long-term compared to non-African populations. Using pairwise sequentially Markovian (PSMC) models on whole-genome sequences, African populations exhibit historical Ne of approximately 10,000–20,000 individuals from 100,000 to 10,000 years ago, reflecting stable demographics in the continent of origin. In contrast, non-African populations experienced a severe bottleneck during the Out-of-Africa (OOA) migration around 50,000–70,000 years ago, reducing Ne to about 1,200–2,000, as evidenced by patterns and simulations. Recent extensions with SMC++ on African datasets confirm these dynamics, showing regional variations like higher Ne in due to agricultural expansions. A 2020 whole-genome study of 426 Africans identified 3.3 million previously unknown variants, with 75% absent from non-African databases, enriching understanding of adaptive traits and population-specific alleles. These findings, from initiatives like H3Africa, highlight the need for Africa-centric references to avoid biases in global genomic research. A 2023 study analyzing autosomal data from 1,333 individuals across over 150 ethnic groups in five countries further revealed fine-scale population structure and migration patterns within African nations.

Ancient DNA Insights

Advances and Challenges in African Ancient DNA

The retrieval and analysis of ancient DNA (aDNA) from remains face significant challenges primarily due to environmental factors. High temperatures and across much of the accelerate DNA degradation, resulting in fragmented and low-yield genetic material compared to temperate regions. Prior to 2020, fewer than 100 ancient genomes had been successfully sequenced, starkly contrasting with thousands from and , which has limited insights into prehistoric . Recent methodological advances have begun to address these obstacles, ushering in an " revolution" in between 2024 and 2025 that has produced over 50 new genomes. Improved extraction techniques, such as sampling the dense petrous portion of the , have enhanced DNA recovery rates from poorly preserved skeletal remains. Additionally, targeted enrichment methods, including hybridization capture for specific genomic regions, allow for efficient sequencing even from low-input samples, enabling broader application of next-generation sequencing technologies. Ethical considerations are integral to this progress, emphasizing and equitable data access to ensure benefits reach African researchers and populations. A 2024 vision outlined in the American Journal of Human Genetics advocates for collaborative frameworks that prioritize local capacity-building and transparent consent processes in studies. Complementary tools, such as integrating with low-coverage genome sequencing (typically 0.1–1× depth), provide chronological context while maximizing data from scarce samples. These developments have profound implications for reconstructing migration patterns in human history.

Key Ancient Genomes and Their Implications

One of the most significant ancient genomes from Africa is that of individuals from the site in , dating to approximately 15,000 years ago and associated with the culture. These genomes reveal a genetic composition of roughly two-thirds ancestry related to Natufian hunter-gatherers from the ancient and one-third sub-Saharan African ancestry, indicating early bidirectional gene flow across the Mediterranean and during the . This admixture profile underscores the deep connections between North African foragers and Eurasian populations, predating the farming dispersals and providing a baseline for tracing subsequent migrations into the . In , the Mota genome from the , dated to about 4,500 years ago, offers a pre-admixture snapshot of indigenous populations. Lacking any detectable Eurasian ancestry, Mota represents a basal East African lineage that diverged early from other African groups, highlighting that the substantial back-migrations from the —evident in modern East Africans—occurred primarily after this period, likely during the . This genome has been instrumental in modeling the timing and scale of Eurasian into the , separating ancient autochthonous components from later overlays. Recent analyses of ancient mitogenomes from , published in 2025, further illuminate post-Roman dynamics, showing that lineages linked to modern Arab populations in the region have relatively recent origins, with many tracing to migrations from the within the last 1,500 years. Complementing this, 2025 studies on Green Sahara and eastern ancient demonstrate high continuity of local forager ancestry from the Epipaleolithic through the , interspersed with targeted inputs from Iberian farmers and Levantine sources around 7,000–5,000 years ago. These findings reveal a layered history of isolation punctuated by episodic exchanges, rather than wholesale population replacements. A 2024 study from Oakhurst Rockshelter in sequenced genome-wide data from 13 individuals dating between approximately 10,000 and 1,300 years ago, revealing over 9,000 years of genetic continuity in local forager populations with limited admixture from external sources until the last few millennia, underscoring long-term isolation in . Key implications of these genomes extend to continent-wide , such as confirming back-migrations' role in southern Africa's diversity; for instance, a 2023 genomic survey of Angolan Desert groups identifies unique pre-Bantu ancestries diverging around 10,000–5,000 years ago, consistent with ancient Eurasian inflows admixing with local lineages. Similarly, integrated evidence refines the Bantu expansion's timing, placing the primary demographic spread from West-Central into southern and eastern regions between 3,000 and 2,000 years ago, driven by farming and ironworking dispersals that reshaped linguistic and genetic landscapes. Overall, these ancient baselines resolve "ghost" admixtures in modern genomes—unexplained archaic or migratory components—by distinguishing deep African divergences from Eurasian contributions, enhancing models of 's genetic complexity. Despite preservation challenges in 's warm environments, improved low-coverage sequencing has made such recoveries feasible.

Regional Genetic Histories

North Africa

North African populations exhibit a distinctive genetic profile shaped by ancient back-to-Africa migrations and subsequent regional interactions. The dominant Y-chromosomal is E1b1b (also known as E-M215), which predominates across the region and reaches frequencies of up to 80% in some Berber groups, such as those in and , reflecting deep autochthonous roots potentially originating in or the before expanding westward. Complementing this, (mtDNA) lineages are marked by high prevalence of U6, a of the Eurasian macro- U, alongside derivatives of H; U6, in particular, is linked to the culture dating to approximately 20,000 years ago, with coalescence estimates for its North African subclades around 26,000 years ago and frequencies up to 20% in Berber populations. Admixture analyses reveal a complex history of , with modern North Africans typically carrying 10–30% sub-Saharan ancestry alongside 50–80% Eurasian components, including Near Eastern and European influences, though proportions vary by and —such as higher sub-Saharan input (up to 55%) in southern Moroccan populations from migrations around 1,200 years ago. A 2024 demographic modeling study highlights differential origins: Amazigh (Berber) groups trace continuity to Epipaleolithic back-to-Africa expansions around 18,000–22,000 years ago with limited recent admixture (~5% sub-Saharan and ~5–10% Middle Eastern), while Arab-identifying populations show a more recent divergence from Middle Eastern sources approximately 1,600 years ago, associated with the period rather than ancient events, incorporating ~10% additional Middle Eastern ancestry. Unique genetic features include evidence from ancient DNA at the site in , where 15,000-year-old individuals display substantial early Eurasian ancestry (~60–70% affinity to Natufian-like Near Eastern populations) mixed with sub-Saharan components, underscoring prehistoric trans-Saharan connections without significant archaic admixture signals beyond typical from Eurasian backflow. In contrast to sub-Saharan African genomes, North African profiles show comparatively low signals of ghost archaic , likely due to the diluting effect of Eurasian . Recent mitogenome research from 2025, analyzing over 700 sequences across , , , , and , uncovers post-Roman (~1,500–2,000 years ago) mediated by Mediterranean exchanges, including female lineages from and Iberia; notable examples include North African-specific subclades like H1v (coalescence ~5,400 years ago) and J2a2b1a (~7,400 years ago), which reflect ongoing connectivity via trade routes involving Phoenicians, , and later Islamic expansions.

West Africa

The genetic history of is predominantly shaped by the diversification and expansion of Niger-Congo-speaking populations, who form the majority of the region's inhabitants. Autosomal DNA analyses reveal a distinct clustering of these groups, reflecting shared ancestry and limited external gene flow compared to other African regions. A hallmark of West African paternal lineages is the dominance of Y-chromosomal E1b1a, which reaches frequencies of up to 80% in many populations and serves as a key marker of Bantu-related ancestry. This originated in West-Central Africa and spread widely through migrations, contributing to the genetic continuity across the region. On the maternal side, L1 and L2 are prevalent, comprising a significant portion of the mtDNA pool in groups such as the Yoruba and Mandenka, and tracing back to ancient sub-Saharan African lineages. The , initiating around 5,000 years ago from West-Central Africa, profoundly influenced West African demographics by spreading Niger-Congo languages, , and associated genetic signatures eastward and southward, while involving admixture with local forager populations. from sites like Shum Laka in indicates that these early Bantu migrants encountered and partially assimilated West African forager groups, leading to hybrid ancestries evident in modern coastal and forest populations. Recent 2023 genomic studies of over 400 Nigerian samples highlight fine-scale structure within West African groups, showing close relatedness between Yoruba and Igbo populations alongside subtle differentiation driven by historical migrations and local adaptations. Admixture events in include a minor contribution from an archaic "ghost" lineage, estimated at approximately 8% of the genome in populations like the Yoruba and Mandenka, suggesting interbreeding with an unidentified hominin group distinct from Neanderthals or Denisovans. Eurasian genetic input remains low, typically under 5% in most West African groups, reflecting geographic isolation and limited historical contact with North African or Mediterranean populations. A notable adaptive variant in West African genomes is the Duffy-null allele (FY*0), which occurs at high frequencies—often exceeding 70%—and confers resistance to by preventing parasite invasion of red blood cells, a selective advantage in malaria-endemic environments. This allele's prevalence underscores the role of infectious disease pressures in shaping regional .

Central Africa

Central African populations, particularly the rainforest hunter-gatherer (RHG) groups such as the Biaka and Mbuti Pygmies, exhibit profound genetic isolation and diversity shaped by long-term adaptation to equatorial forest environments. These groups represent some of the deepest branches in the human genetic tree within Africa, with genomic analyses indicating an ancient from other African populations approximately 60,000 years ago. This split predates major migrations like the and underscores the continuity of forager lineages in the despite subsequent interactions with incoming farmers. Uniparental markers highlight the distinct paternal and maternal ancestries of these Central African foragers. Y-chromosomal B2b, a of B-M60, predominates among Biaka and Mbuti Pygmies, reflecting ancient African lineages with limited external . Similarly, L1c is strongly associated with these groups, particularly the Biaka in western Central Africa and Mbuti in the east, comprising a significant portion of their maternal diversity and linking to early dispersals within the . Admixture events have introduced farmer ancestry into these isolated populations, diluting pure forager heritage. The influx of Bantu-speaking agriculturalists around 1,000–2,000 years ago, associated with the broader , contributed substantial autosomal ancestry to RHG groups, with estimates showing up to 15–20% non-forager input in some Biaka and Mbuti samples. This was asymmetrical, primarily from farmers to foragers, and coincided with linguistic and cultural exchanges in the region. Additionally, evidence points to elevated archaic in Central African Pygmies, with approximately 2% of their genomes potentially derived from an unidentified "ghost" archaic hominin that diverged over 600,000 years ago, higher than in many other modern human groups. Recent high-resolution genomic studies, analyzing approximately 500,000 single-nucleotide variants across diverse Central African ethnicities, reveal deep population splits among RHG groups and their divergence from neighboring West and East African clusters. These analyses, incorporating dense sampling from and surrounding areas, demonstrate structured isolation driven by geographic barriers like the Congo rainforest, with effective population sizes remaining small and distinct from Bantu-derived farmers. Such structure persists despite admixture, highlighting the resilience of ancient lineages. Environmental pressures in the pathogen-rich have left signatures of , particularly in immune-related genes among Central African foragers. Whole-genome sequencing of Biaka Pygmies identifies positive selection in loci involved in innate immunity and response to tropical diseases, such as those modulating production and recognition, adaptations likely honed by chronic exposure to diverse microbes in dense forest habitats. These selective sweeps contribute to population-specific immune profiles, distinguishing RHG responses from those of agriculturalist neighbors.

East Africa

East Africa's genetic landscape reflects a complex mosaic of ancient indigenous lineages intertwined with later migrations, particularly among Nilotic, Cushitic, and Bantu-speaking populations, forming a bridge between sub-Saharan and Eurasian ancestries in the Horn of Africa region. Hunter-gatherer groups like the Hadza and Sandawe exhibit deep-rooted paternal lineages dominated by Y-chromosome haplogroups A and B, which trace back to some of the earliest divergences in human history and distinguish them from neighboring agriculturalists. In contrast, Cushitic-speaking peoples, such as those in Ethiopia and Somalia, show high frequencies of Y-haplogroup E1b1b, linked to expansions from Northeast Africa around 10,000–15,000 years ago and associated with early pastoralist adaptations. On the maternal side, mitochondrial DNA haplogroup L3 predominates in East Africa and serves as the basal lineage for the Out-of-Africa migration, with its origins estimated around 70,000 years ago in the region, giving rise to non-African macrohaplogroups M and N. Major demographic events shaped this diversity, including pastoralist migrations between 3,000 and 5,000 years ago that introduced livestock herding and Eurasian genetic input into southern and eastern . These movements, likely involving Nilo-Saharan and Afroasiatic speakers, contributed approximately 15–20% Eurasian ancestry to many East African populations, as evidenced by admixture models from ancient genomes. The genome of an individual from Mota Cave in , dated to about 4,500 years ago, provides a critical pre-admixture baseline, lacking the later Eurasian signals and highlighting the region's indigenous genetic profile before these influxes. Recent studies, including 2023 analyses of whole-genome data from diverse East African groups, have illuminated Nilotic expansions, showing how Nilo-Saharan speakers from and admixed with local foragers and pastoralists, influencing linguistic and genetic patterns across and . This high genetic diversity in and —among the highest globally—stems from overlapping layers of these interactions, with Ethiopian populations spanning much of 's genetic variation due to their ethnolinguistic stratification. Admixture events in include moderate contributions from archaic hominins, detected through excess archaic sequence sharing in sub-Saharan genomes, including those from sub-Saharan groups such as the Mandenka () and Biaka (), suggesting interbreeding events predating 40,000 years ago. Eurasian back-migrations, primarily from farmer-related sources around 3,000 years ago, added further complexity, with the Mota genome confirming that such ancestry was absent in pre-pastoralist East Africans but became widespread thereafter. These components underscore East Africa's role as a dynamic genetic crossroads, with ongoing research revealing nuanced patterns of that enhance understanding of human adaptation in diverse environments.

Southern Africa

Southern Africa's genetic landscape is characterized by the deep-rooted ancestry of the (also known as Khoe-San) peoples, who represent some of the most ancient branches of modern human lineages. These groups, including the San foragers and Khoe herders, harbor the oldest (mtDNA) , which is indigenous to the region and dates back over 100,000 years, with subclades like L0d and L0k being particularly prevalent among them. On the Y-chromosome, Khoisan populations predominantly carry haplogroups A and B, which are among the earliest diverging lineages in human history. Genome-wide analyses indicate that the ancestors of southern African San diverged from other modern human populations more than 200,000 years ago, with the initial split among modern humans estimated between 260,000 and 350,000 years ago, underscoring Southern Africa's role in early . This deep divergence parallels that seen in central African rainforest hunter-gatherers, highlighting a basal split in African . The arrival of Bantu-speaking agriculturalists around 1,500 years ago introduced significant into populations, primarily through Y-chromosome E1b1a, which became modal in these expanding groups. In populations, this Bantu admixture typically ranges from 10% to 20% in less admixed groups, though it can reach higher levels in others, and occurred within the past 1,200 years, often involving sex-biased favoring Bantu male contributions. A 2023 study of populations in the Angolan Desert revealed unique pre-Bantu ancestry components, with small-scale forager groups exhibiting 10-14% southern African forager heritage and admixture events dated to 600-1,100 years ago, demonstrating regionally specific divergences not seen elsewhere in . Eurasian genetic admixture in Southern Africa remained low prior to the colonial era, with most Khoisan groups showing minimal west Eurasian ancestry until European settlement in the 17th century, which substantially increased European and Asian components through colonial interactions. However, some precolonial west Eurasian gene flow, likely indirect via eastern African pastoralists, occurred 900-1,800 years ago, contributing a few percent to Khoisan genomes. Additionally, Khoe-San populations exhibit the strongest signals of archaic admixture in Africa, with an average of nearly 500 putative ghost archaic haplotypes per genome—5 to 15 times more than in non-Africans—suggesting introgression from an unidentified archaic hominin, potentially influencing local genetic diversity. Genetic adaptations in populations reflect their long-term residence in arid environments, with signatures of positive selection evident for traits related to skin pigmentation and metabolism. For instance, variants near genes such as OCA2, , SLC24A5, and MITF show enrichment in San groups, associated with lighter skin tones adapted to variable UV exposure in southern latitudes. Metabolic adaptations are also apparent, including selection signals in loci like PDPK1, which may relate to energy efficiency in low-resource arid settings.

Medical and Applied Genomics

Disease-Associated Genetic Variants

One of the most prominent examples of disease-associated genetic variants in African populations is the hemoglobin S (HbS) , responsible for and disease, which provides against severe . The HbS mutation (rs334 in the HBB gene) is prevalent in malaria-endemic regions, with heterozygote frequencies reaching 20-30% in parts of West and , where it reduces the risk of severe malaria by approximately 90% in carriers (HbAS ) through mechanisms such as impaired parasite growth in sickled erythrocytes. This balancing selection maintains the allele despite the homozygous HbSS state causing sickle cell anemia, a classic case of evolutionary adaptation driven by malaria pressure. Similarly, (G6PD) deficiency, particularly the African variant G6PD A- (c.376A>G; c.202G>A), confers resistance to severe , especially in hemizygous males and heterozygous females in West and Central African populations where deficiency affects 15-25% of males. This X-linked variant reduces risk by 46-58% via oxidative stress that disrupts parasite development in red blood cells, exemplifying that sustains its high frequency despite hemolytic risks. Other notable variants include the APOL1 G1 (rs73885319) and G2 (rs71785313) risk alleles, which are associated with increased susceptibility to , including , and trace primarily to West African ancestry where they occur in up to 30% of individuals. These variants likely evolved as adaptations against trypanosome infection but now elevate renal disease risk in descendants, including . The Duffy-negative (FY0 or FYBES allele, rs2814778), nearly fixed (>90%) across , provides strong resistance to by preventing parasite invasion of erythrocytes lacking the Duffy antigen receptor. For HIV resistance, the CCR5-Δ32 deletion is rare or absent in African populations, including Zimbabwean cohorts, where it occurs at frequencies below 1%, limiting its protective role against -1 entry compared to European populations. However, local variants such as polymorphisms in KIR and HLA genes have been identified in Zimbabwean cohorts, influencing control and immune activation, suggesting population-specific adaptations. African-specific genomic databases, such as those from the H3Africa initiative, have enabled the reclassification of variants of uncertain significance (VUS) in disease-associated genes, reducing misannotations by incorporating diverse African allele frequencies and functional data. For instance, 2024 studies in South African breast cancer cohorts reclassified up to 27% of VUS as benign using local genomic references, highlighting how underrepresentation in global databases previously led to overestimation of pathogenic variants in African genomes.

Precision Medicine and Equity in African Genomics

The unparalleled genetic diversity of African populations offers significant opportunities for advancing drug discovery and precision medicine, as this variation can uncover novel phenotype-genotype associations that are underrepresented in global datasets. A 2025 review emphasizes how biobanks linking African genomic data to diverse phenotypes could accelerate the identification of therapeutic targets, particularly for diseases with complex polygenic architectures. For instance, the higher prevalence of certain adaptive variants in African genomes may inform the development of more effective treatments tailored to regional health challenges. Despite these prospects, substantial gaps persist in the representation of African ancestry in genomic , hindering equitable applications in . In published genome-wide association studies (GWAS), individuals of African ancestry comprise only about 1.1%, compared to 86% of European ancestry, leading to biased risk predictions and limited insights into mechanisms relevant to African populations. This underrepresentation exacerbates health disparities, as polygenic risk scores derived primarily from European data perform poorly across African contexts. In 2024, researchers called for landmark-driven approaches to equitable (aDNA) and population studies in , advocating for African-led initiatives to prioritize local ethical frameworks and . Key initiatives like the Human Heredity and Health in Africa (H3Africa) project have addressed these challenges by generating vast genomic datasets through collaborative biobanking and capacity-building efforts across the continent. Launched to empower African researchers, H3Africa has produced resources that enhance understanding of genetic-environmental interactions in diseases prevalent in Africa, fostering benefits. For example, pharmacogenomic studies supported by such data have explored hydroxyurea response in patients in , identifying variants that optimize and reduce adverse effects in African cohorts. Looking ahead, integrating advances from 2023 to 2025—such as expanded biobanks and AI-driven analyses—holds promise for that accounts for Africa's diverse genetic landscapes. These developments could enable tailored interventions, like ancestry-informed , to improve outcomes in resource-limited settings while promoting equity through inclusive . By building on disease-associated genetic variants as foundational data, future efforts aim to bridge the equity gap and translate genomic insights into accessible healthcare across African populations.

References

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