Kimura, Motoo

Abstract

Motoo Kimura (1924–94) was a pioneering population geneticist from Japan, who studied evolutionary processes at the molecular level using mathematical models. He is most known as an advocate of the neutral theory of molecular evolution having published this idea in Nature in 1968. He analyzed molecular data available at that time by using the molecular clock hypothesis, and realized that if he followed J.B.S. Haldane’s concept of genetic load, the genetic load for those sample species he studied was too large for them to avoid extinction. Therefore, Kimura proposed the neutral theory of molecular evolution, where he argued that random “genetic drift,” rather than natural selection, is the main cause of evolutionary processes at the molecular level. Kimura slightly modified his theory over the years as new data became available. Kimura’s paper in Nature in 1968, his masterpiece, The Neutral Theory of Molecular Evolution in 1983 and Seibutsu shinka wo kangaeru (My Views on Evolution) in 1988 exemplify successive versions of his theory.