Natural Selection in New Gene Evolution

摘要

Origination and evolution of new genes are a general process in various organisms, which consists of initial mutational event, subsequent fixation in species, and continuous evolution to optimize functions. This neofunctionalization process has been thought to be governed by positive selection supported by a few case analyses, although more rigorous analysis is expected. However, many observations in Drosophila and mammals using computational and experimental genomic tools are consistent with the assumed adaptive evolution, including the elevated sequence substitutions of new genes in their early stages, the molecular population genetics of the exon-intron structure in the Jingwei gene in the African species, the rising of new biochemical functions with the new genes, and the directional movement of male biased genes between the X chromosome and autosomes. The initial step of new gene evolution has been shown to form an expected level of the copy number variation in Drosophila dominated by natural selection. With the outstanding efforts of many colleagues, the new gene evolution has become an active area of molecular evolution studies, since the early 1990s when the first new gene, Jingwei, in Drosophila was observed. It can be predicted that the era of ge-nomics which has come would see more fruitful exploration into the fascinating process of new gene evolution in the near future.