哺乳類の分子遺伝学

Recent advances in molecular genetics of mammals,including construction of genetic linkage maps, identification of mutations responsible for inheritable diseases, mapping of quantitative trait loci,and findings about sex determination are reviewed in the present paper. Information about genomes of humans,laboratory animals and domestic animals has been rapidly accumulated in the last decade. Establishment of polymorphic linkage markers and construction of chromosomal linkage maps of mammalian species enable us to identify the genes responsible for particular genetic traits. Various mutations have been found in genes responsible for human inheritable diseases. We have constructed genetic linkage maps for rats and identified a mutation responsible for mucopoly saccharidosis in rats. Mapping of loci affecting the quantitative traits of domestic animals, including growth rate, litter size, and milk production, as well as identification of the genes responsible for inheritable diseases of domestic animals, are also being carried out.Recently, the testis-determining gene on the Y chromosome, which determine the sex of mammals by defferentiating the testis in the embryos, have been identified in humans and mice. Functions of the sex-determining gene in sexual differentiation of the mammalian embryos have been intensively analyzed. We have found a sexual difference in the growth rate of mouse preimplantation embryos. An application of the recent findings in the molecular genetics of mammals will contribute to animal science and agricultural science.