Motoo Kimura (13 November 1924 – 13 November 1994) was a Japanese mathematician and biologist. He was known for introducing the neutral theory of molecular evolution in 1968. "Calculating the rate of evolution in terms of nucleotide substitutions seems to give a value so high that many of the mutations involved must be neutral ones".
He became one of the most influential theoretical population geneticists:
Motoo Kimura's research contributions can be divided into two parts. The first is a series of papers on theoretical population genetics, the quality and quantity of which place him as the successor to the great trinity, R.A. Fisher, J.B.S. Haldane and Sewall Wright. The second is his neutral theory, the idea that the bulk of molecular evolutionary changes are driven by mutation and random chance, rather than by natural selection.
Kimura was heavily influenced by Sewall Wright; the main distinction being that Wright was mainly interested in populations, whereas the core of Motoo's work was in changes at the molecular level. Modified versions of Kimura's ideas are still in use today.
In 1992, Kimura received the Darwin Medal from the Royal Society, and the following year he was made a Foreign Member of the Royal Society.
- Weldon Memorial Prize (UK), 1965.
- Japan Academy Prize, 1968.
- Order of Culture (Japan), 1976.
- Royal Society (UK), Darwin Medal in 1992; Foreign member, 1993.
- Motoo Kimura (木村 資生 Kimura Motoo )
- Kimura, Motoo 1968. Evolutionary rate at the molecular level. Nature 217, 624–626
- Crow, James F. 1997. Motoo Kimura, 13 November 1924 – 13 November 1994". Biographical Memoirs of Fellows of the Royal Society 43: 254–265. 
- Provine, William B. 1986. Sewall Wright and evolutionary biology. Chicago. p463–484
- Crow, James F. (1995). "Motoo Kimura (1924-1994)". Genetics 140 (1): 1–5. PMC 1206539. PMID 7635277.
- Weldon Memorial Prize, Past Prize-winnrs, Motoo Kimura, 1965; retrieved 2012-5-29.
- Japan Academy Prize, Japan Academy Prize, 1968; retrieved 2012-5-29.
- Ohta, Tomoko. "Origin of the neutral and nearly neutral theories of evolution," Journal of Bioscience, Vol. 28, No. 4, June 2003, p. 372; image of Kimura wearing Order of Culture around his neck; retrieved 2012-5-29.
- Royal Society, archived record