A Study of Relationship between Mammalian Specific Features and Gene Diversification on the Basis of Genome Comparisons.

在进化生物学领域，了解形态水平的进化与分子水平的进化之间的关系是非常重要的。哺乳动物具有鸟类和爬行动物所没有的一些独特的形态特征：体毛、脑容量大、胎动、嗅觉灵敏。为了探讨这些哺乳动物特有的形态特征与参与这些特征进化的基因多样性之间的关系，我们对人类、小鼠、牛、负鼠、鸡、非洲爪蛙等几种脊椎动物的基因组序列进行了比较。对这些物种的基因进行了详尽的同源性研究，结果表明203个基因家族的成员仅在哺乳动物谱系中通过重复而多样化。在这些基因家族中，我还发现有几个与大脑或中枢神经系统发育有关的基因是在哺乳动物进化的早期通过复制产生的。该研究结果已在日本进化研究学会第7届年会上发表。

In the field of evolutionary biology, it is very important to understand the relationship between evolution at the morphological level and that at the molecular level. Mammals have some unique morphological characters, which are not found in birds and reptiles: body hair, big brain, viviparity, and sensitive olfactory organ. In order to investigate the relationship between these mammalian specific morphological features and diversification of genes that were involved in the evolution of these characters, genome sequences of several vertebrate species including human, mouse, bovine, opossum, chicken, African clawed frog, etc. are compared. An exhaustive homology search of the genes among these species suggested that members of 203 gene families were diversified by duplications only in the lineage of mammals. In these gene families, I also found that several genes involved in the development of brain or central nervous system were produced by duplications in the early stage of mammalian evolution. The result of this study had been reported in the 7th annual meeting of the Society of Evolutionary Studies, Japan.