| Co-Investigator(Kenkyū-buntansha) |
IWABE Naoyuki Kyoto Univ., Graduate School of Science, Assistant Professor, 大学院・理学研究科, 助手 (80263060)
KUMA Kei-ichi Kyoto Univ., Graduate School of Science, Assistant Professor, 大学院・理学研究科, 助手 (10221938)
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| Research Abstract |
Animals evolved a variety of gene families involved in cell-cell communication and developmental control by gene duplication and domain shuffling. Each family comprises several subtypes or subfamilies with distinct structures and functions which diverged by gene duplications and domain shuffling before the divergence of parazoans and eumetazoans. Since the separation from protostomes, vertebrates expanded the multiplicity of members (isoforms) in the same subfamily by further gene duplications in their early evolution before the fish-tetrapod split. To know the dates of isoform duplications more closely, we have conducted isolation and sequencing of genes belonging to four different subtypes of the protein tyrosine kinase family, five subtypes of protein tyrosine phosphatase family, and other three gene families from Branchiostoma belcheri, an amphioxus, Eptatretus burgeri, a hagfsh and Lampetra reissneri, a lamprey. From a phylogenetic tree of each subfamily inferred from a maximum likelihood (ML) method, together with a bootstrap analysis based on the ML method, we have shown that the isoform duplications frequently occurred in the early evolution of vertebrates around or just before the divergence of cyclostomes and gnathostomes by gene dupli-cations and possibly chromosomal duplications.
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