Masatoshi Nei

Masatoshi Nei (根井正利, Nei Masatoshi; January 2, 1931 – May 18, 2023) was a Japanese-born American evolutionary biologist.

Masatoshi Nei was born in 1931 in Miyazaki Prefecture, on Kyūshū Island, Japan.

He received a Bachelor of Science degree from the University of Miyazaki in 1953, and published his first article, on the mathematics of plant breeding, that same year. In 1959, he completed his doctoral degree at Kyoto University on quantitative genetics for crop improvement.

For the next decade, Nei worked in Japan, including as a research scientist at the National Institute of Radiological Sciences, before emigrating to the United States in 1969.

Nei was associate professor and professor of biology at Brown University from 1969 to 1972 and professor of population genetics at the Center for Demographic and Population Genetics, University of Texas Health Science Center at Houston (UTHealth), from 1972 to 1990.

He was later an Evan Pugh Professor of Biology at Pennsylvania State University and Director of the Institute of Molecular Evolutionary Genetics, working there from 1990 to 2015.

From 2015, Nei was affiliated with the Department of Biology at Temple University as an adjunct Laura H. Carnell Professor.

Acting alone or working with his students, he has continuously developed statistical methods for studying molecular evolution taking into account discoveries in molecular biology. He has also developed concepts in evolutionary theory and advanced the theory of mutation-driven evolution.