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，理解形态水平上的进化与分子水平上的进化之间的关系非常重要。哺乳动物具有一些鸟类和爬行动物所没有的独特形态特征：体毛、大脑大、胎生和敏感的嗅觉器官。为了研究这些哺乳动物特定形态特征与参与这些特征进化的基因多样化之间的关系，对包括人类、小鼠、牛、负鼠、鸡、非洲爪蛙等在内的几种脊椎动物的基因组序列进行了比较。对这些物种中基因的详尽同源性搜索表明，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，我还发现一些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阶段通过重复产生的。该研究结果已在日本进化学会第七届年会上报告。

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.