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Neanderthal genetics
Neanderthal genetics testing became possible in the 1990s with advances in ancient DNA analysis. In 2008, the Neanderthal genome project published the full sequence Neanderthal mitochondrial DNA (mtDNA), and in 2010 the full Neanderthal genome. Genetic data is useful in testing hypotheses about Neanderthal evolution and their divergence from early modern humans, as well as understanding Neanderthal demography, and interbreeding between archaic and modern humans.
Modern humans and Neanderthals had multiple different interbreeding episodes, but Neanderthal-derived genes in the present-day human genome descends from an episode 250,000 years ago probably in Eurasia, and 47,000 to 65,000 years ago in the Near East. While 20% of the Neanderthal genome survives today, most people only carry about a few percentage points of Neanderthal DNA, and most Neanderthal-derived DNA is non-coding. Neanderthals maintained a low genetic diversity and suffered from inbreeding depression; consequently most Neanderthal genes were probably selected out of the gene pool. Barring hybrid incompatibility or negative selection, most Neanderthal DNA may descend from the children of modern human females and Neanderthal males. Neanderthals also interbred with Denisovans in the Siberian Altai Mountains.
Genetic studies on Neanderthal ancient DNA became possible in the late 1990s. In July 2006, the Max Planck Institute for Evolutionary Anthropology and 454 Life Sciences announced that they would sequence the Neanderthal genome over the next two years. It was hoped the comparison would expand understanding of Neanderthals, as well as the evolution of humans and human brains. They published the full sequence Neanderthal mitochondrial DNA (mtDNA) in 2008. Svante Pääbo noted that, "Contamination was indeed an issue," and they eventually realised that 11% of their mtDNA sample was modern human DNA. Since then, more of the preparation work has been done in clean areas and 4-base pair 'tags' have been added to the DNA as soon as it is extracted so the Neanderthal DNA can be identified.[citation needed]
The first Neanderthal genome sequence was published in 2010, and strongly indicated interbreeding between Neanderthals and early modern humans. This was based on three specimens in Vindija Cave, Croatia, which contained almost 4% archaic DNA (allowing for near complete sequencing of the genome). However, there was approximately 1 error for every 200 letters (base pairs) based on the implausibly high mutation rate, probably due to the preservation of the sample. In 2012, British-American geneticist Graham Coop hypothesised that they instead found evidence of a different archaic human species interbreeding with modern humans, which was disproven in 2013 by the sequencing of a high-quality Neanderthal genome preserved in a 50,000 year old toe (phalanx) bone from Denisova Cave, Siberia.
A visualisation map of the reference modern-human containing the genome regions with high degree of similarity or with novelty according to a 50,000 year old Neanderthal from the Siberian Altai Mountains has been built by Pratas et al.
Neanderthal genomes sequenced include those from Denisova Cave including an offspring of a Neanderthal and a Denisovan, from Chagyrskaya Cave, from Vindija Cave, Mezmaiskaya cave, Les Cottés cave, Goyet Caves and Spy Cave, Hohlenstein-Stadel and Scladina caves Galería de las Estatuas and Gibraltar.
Genetic data has been used to test various hypotheses about Neanderthal evolution and identify the last common ancestor (LCA) of Neanderthals and modern humans. Numerous dates have been suggested, such as 538–315, 553–321, 565–503, 654–475, 690–550, 765–550, 741–317, and 800–520,000 years ago; and a dental analysis concluded before 800,000 years ago.
The date of around 250,000 years ago cites "H. helmei" as being the LCA, and the split is associated with the Levallois technique of making stone tools. The date of about 400,000 years ago uses H. heidelbergensis as the LCA. Estimates of 600,000 years ago assume that "H. rhodesiensis" was the LCA, which split off into a modern human lineage and a Neanderthal/H. heidelbergensis lineage. 800,000 years ago has H. antecessor as the LCA, but different variations of this model would push the date back to 1 million years ago. A 2020 analysis of H. antecessor enamel proteomes suggests that H. antecessor is related but not a direct ancestor.
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Neanderthal genetics
Neanderthal genetics testing became possible in the 1990s with advances in ancient DNA analysis. In 2008, the Neanderthal genome project published the full sequence Neanderthal mitochondrial DNA (mtDNA), and in 2010 the full Neanderthal genome. Genetic data is useful in testing hypotheses about Neanderthal evolution and their divergence from early modern humans, as well as understanding Neanderthal demography, and interbreeding between archaic and modern humans.
Modern humans and Neanderthals had multiple different interbreeding episodes, but Neanderthal-derived genes in the present-day human genome descends from an episode 250,000 years ago probably in Eurasia, and 47,000 to 65,000 years ago in the Near East. While 20% of the Neanderthal genome survives today, most people only carry about a few percentage points of Neanderthal DNA, and most Neanderthal-derived DNA is non-coding. Neanderthals maintained a low genetic diversity and suffered from inbreeding depression; consequently most Neanderthal genes were probably selected out of the gene pool. Barring hybrid incompatibility or negative selection, most Neanderthal DNA may descend from the children of modern human females and Neanderthal males. Neanderthals also interbred with Denisovans in the Siberian Altai Mountains.
Genetic studies on Neanderthal ancient DNA became possible in the late 1990s. In July 2006, the Max Planck Institute for Evolutionary Anthropology and 454 Life Sciences announced that they would sequence the Neanderthal genome over the next two years. It was hoped the comparison would expand understanding of Neanderthals, as well as the evolution of humans and human brains. They published the full sequence Neanderthal mitochondrial DNA (mtDNA) in 2008. Svante Pääbo noted that, "Contamination was indeed an issue," and they eventually realised that 11% of their mtDNA sample was modern human DNA. Since then, more of the preparation work has been done in clean areas and 4-base pair 'tags' have been added to the DNA as soon as it is extracted so the Neanderthal DNA can be identified.[citation needed]
The first Neanderthal genome sequence was published in 2010, and strongly indicated interbreeding between Neanderthals and early modern humans. This was based on three specimens in Vindija Cave, Croatia, which contained almost 4% archaic DNA (allowing for near complete sequencing of the genome). However, there was approximately 1 error for every 200 letters (base pairs) based on the implausibly high mutation rate, probably due to the preservation of the sample. In 2012, British-American geneticist Graham Coop hypothesised that they instead found evidence of a different archaic human species interbreeding with modern humans, which was disproven in 2013 by the sequencing of a high-quality Neanderthal genome preserved in a 50,000 year old toe (phalanx) bone from Denisova Cave, Siberia.
A visualisation map of the reference modern-human containing the genome regions with high degree of similarity or with novelty according to a 50,000 year old Neanderthal from the Siberian Altai Mountains has been built by Pratas et al.
Neanderthal genomes sequenced include those from Denisova Cave including an offspring of a Neanderthal and a Denisovan, from Chagyrskaya Cave, from Vindija Cave, Mezmaiskaya cave, Les Cottés cave, Goyet Caves and Spy Cave, Hohlenstein-Stadel and Scladina caves Galería de las Estatuas and Gibraltar.
Genetic data has been used to test various hypotheses about Neanderthal evolution and identify the last common ancestor (LCA) of Neanderthals and modern humans. Numerous dates have been suggested, such as 538–315, 553–321, 565–503, 654–475, 690–550, 765–550, 741–317, and 800–520,000 years ago; and a dental analysis concluded before 800,000 years ago.
The date of around 250,000 years ago cites "H. helmei" as being the LCA, and the split is associated with the Levallois technique of making stone tools. The date of about 400,000 years ago uses H. heidelbergensis as the LCA. Estimates of 600,000 years ago assume that "H. rhodesiensis" was the LCA, which split off into a modern human lineage and a Neanderthal/H. heidelbergensis lineage. 800,000 years ago has H. antecessor as the LCA, but different variations of this model would push the date back to 1 million years ago. A 2020 analysis of H. antecessor enamel proteomes suggests that H. antecessor is related but not a direct ancestor.