The Genetics Society of America annually honors members who have made outstanding contributions to genetics. The Thomas Hunt Morgan Medal recognizes a lifetime contribution to the science of genetics. The Genetics Society of America Medal recognizes particularly outstanding contributions to the science of genetics within the past 15 years. The George W. Beadle Medal recognizes distinguished service to the field of genetics and the community of geneticists. We are pleased to announce the 2006 awards.
MASATOSHI Nei has been a major contributor to population and evolutionary genetics theory throughout his career. He is one of a select group to have a statistic named for him: “Nei's genetic distance” is a cornerstone of population genetic analyses. His body of work includes two influential textbooks and a remarkable 55 (of nearly 300) articles with over 100 citations each, 9 of which have over 1100 citations and 1 of which has over 12,000.
When Nei received the International Prize for Biology in 2002, the Japan Society for the Promotion of Science said: “Through these achievements, Dr. Nei has not only made the latest findings at the molecular level available to evolutionary biologists, but has contributed greatly to the birth of molecular evolutionary biology and its establishment as a positive science in which hypotheses can be verified quantitatively, rather than being discussed solely on a conceptual level.”
Nei's work on genetic distances began with an American Naturalist article in 1972. He presented an elegant statistic involving allele frequencies from two populations that, under the infinite alleles mutation model, had an expected value proportional to the time since those populations had diverged from an ancestral population. The measure therefore provided a natural basis for reconstructing phylogenies and it was quickly adopted for distance-based methods for building evolutionary trees. Nei provided further discussion of the sampling properties of his distance statistic in Genetics in 1978. His most widely cited work is his 1987 article with Saitou in Molecular Biology and Evolution, which introduced the “neighbor-joining method” for phylogeny reconstruction. This method starts with a star-like tree and produces a unique tree by minimizing the sum of branch lengths at each stage of a recursive clustering of the taxonomic units.
Nei's early work came at the height of the selection vs. neutrality debate that followed the discovery, by starch-gel electrophoresis, of large amounts of genetic variation for protein variants. Nei and his students devised and applied several tests of the neutral hypothesis and so contributed to an acceptance of this theory in many situations. His 1975 book Molecular Population Genetics laid out much of the theory known at that time and was followed by the masterly Molecular Evolutionary Genetics in 1987 and three other jointly written books.
Although Nei has produced a great body of work in statistical genetics, he was trained as a biologist and has been able to translate his data analyses into increasing our understanding of the mechanisms of evolution. He posited an African origin of modern humans in a 1974 article in the American Journal of Human Genetics and has provided details on the geographic pathways of human expansion in several subsequent articles. He has had a particular interest in the generation and maintenance of variation in the vertebrate immune system. His 1988 Nature article on patterns of nucleotide diversity at MHC class I loci suggested the action of overdominant selection. Nei's work on MHC multigene families led him to formulate a “birth-and-death evolution” model for the fate of members of a multigene family after gene duplication. His thinking over the past 40 years has led him to a view of evolution that he terms “neomutationism,” whereby the driving force of evolution is mutation, with natural selection being secondary. This view is argued very clearly in a 2005 review article in Molecular Biology and Evolution that is likely to become a major reference for future workers.
Masatoshi Nei has played many leading roles in population and evolutionary genetics. He has trained >40 graduate and postdoctoral students, who themselves read like a Who's Who in the field. In addition to his publications, he and his group have written and distributed software packages, including MEGA and MEP.
Nei received his formal training at Miyazaki and Kyoto universities in Japan and held positions in Japan before moving to the United States. He had postdoctoral training at the University of California at Davis and at North Carolina State University and was on the faculty briefly at Brown University. For 18 years, from 1972 to 1990, he was at the heart of a very productive group at the Center for Demographic and Population Genetics of the University of Texas at Houston. In 1990 Nei moved to Penn State University to become Director of the Institute of Molecular Evolutionary Genetics and later also became the Evan Pugh Professor of Biology. Nei has been honored by election to the National Academy of Sciences of the United States of America and by fellowship in the American Academy of Arts and Sciences and the American Association for the Advancement of Science. Among his many other honors, he received the 2002 International Prize for Biology, presented in the presence of the Emperor and Empress of Japan. In his remarks at the ceremony, the Emperor said that he himself had used neighbor-joining to construct a phylogenetic tree for the gobioid fishes that he studies. In what must be at least as satisfying a recognition from his peers, the Society for Molecular Biology and Evolution, of which Nei is the cofounder, has established the Masatoshi Nei Annual Lecture.
Masatoshi Nei is a long-time member of the Genetics Society of America and a frequent publisher in Genetics. He has served on the Editorial Board of this journal. The Society is pleased to present him with the 2006 Thomas Hunt Morgan Medal, and I know that Masatoshi is proud to receive the award: in Chapter 14 of his Molecular Population Genetics he quotes a passage from Morgan's The Scientific Basis of Evolution, which shows both Morgan's deep understanding of evolution and the consistency of Nei's own work with that of Morgan's.
Masatoshi Nei
- Copyright © 2006 by the Genetics Society of America
