Masatoshi Nei

Masatoshi Nei is Professor of Biology at Pennsylvania State University and Director of the Institute of Molecular Evolutionary Genetics. Nei is co-founder of the journal Molecular Biology and Evolution, together with Walter M. Fitch. He was born in 1931 in Miyazaki Prefecture, in Kyushu Island, Japan.

He made important contributions to the fields of the evolutionary genetics and molecular evolution, and coined the term Molecular Population Genetics, in reference to the use molecular data in the population genetics field. Among other contributions, he developed the most used statistic to measure the genetic distance between populations (Nei's genetic distance), and the widely used Neighbor-joining method to reconstruct phylogenetic trees (in collaboration with Naruya Saitou). He also pointed out that the variation in natural populations accommodates the expectation of the neutral theory of evolution, as proposed by Kimura, Jukes and King.

He made intellectual contributions about the mechanisms of the evolutionary process, though his vision is still controversial. Dr Nei argues that the Natural Selection is not a creative force, and that Mutation itself is the driver of the evolutionary process. That is, even the environment remains constant, the appearance of a novel beneficial mutation will give selective advantage to an individual, and a dramatic change in the environment most often is lethal to a population because the “appropriate” allele is not in the population, and the population will survive if mutation provides it. That idea is based on original statements of Thomas Morgan and is also a consequence of the neutral theory of evolution. This is a straightforward conclusion of the view that natural populations tends to reduce the genetic variation, opposite to the statements of the neodarwinian vision in which a great variation is maintained by overdominance and other mechanisms (as defended by Dobzhansky and Gillespie among others).

He was laureate with the International Prize for Biology in 2002, and he is member of the National Academy of Sciences since 1997. Dr Nei still scientifically active, developing his work mainly in the evolution of duplicated genes.

References

• Nei, M. (1971) Identity of genes and genetic distance between populations. Genetics. 68:S47.
• Nei, M. (1975) Molecular Population Genetics and Evolution. North-Holland, Amsterdam and New York.
• Nei, M. (1987) Molecular Evolutionary Genetics. Columbia University Press, New York.
• Saitou, N. and M. Nei (1987) The neighbor-joining method: a new method for reconstructing phylogenetic trees. Molecular Biology and Evolution. 4:406-425.
• Nei, M., and S. Kumar (2000) Molecular Evolution and Phylogenetics. Oxford University Press, Oxford.
• Nei, M. (2005) Selectionism and neutralism in molecular evolution. Molecular Biology and Evolution. 22:2318-2342.