Molecular Genetics of Mammals

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.
近年の分子生物学の発展は、ヒトを含む哺乳類の遺伝学にも大きな変化をもたらしている。すなわち、表現型を主な対象とした従来の遺伝学から、DNAをはじめとする分子を対象とした遺伝学へとその中心は移行しつつある。この傾向に拍車をかけたのがここ数年話題になることの多いヒトゲノムプロジェクトであり、またヒトの遺伝病の原因遺伝子の解析と遺伝子診断、遺伝子治療の進展である。農学や畜産学の分野でも、分子育種という概念が確立しつつあり、本論文ではヒト、家畜および実験動物を対象とした哺乳類の分子遺伝学の最近の動向について、我々の研究結果を含めて概説したい。