2013 Fiscal Year Final Research Report

Identification of novel gastric systems by comparing genomic sequences between stomachless fishes and true stomach fishes

Research Project

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Project/Area Number	24651211
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Single-year Grants
Research Field	Genome biology
Research Institution	Tokyo Institute of Technology
Principal Investigator	Kato Akira 東京工業大学, 生命理工学研究科, 助教 (40311336)
Co-Investigator(Kenkyū-buntansha)	竹井祥郎東京大学, 大気海洋研究所, 教授 (10129249)
Co-Investigator(Renkei-kenkyūsha)	KUSAKABE Makoto 東京大学, 大気海洋研究所, 助教 (40451893) HIROSE Shigehisa 東京工業大学, 生命理工学研究科, 教授 (10134199)
Research Collaborator	WATANABE Taro 東京大学, 大気海洋研究所, 技術職員 Romero Michael F. Mayo Clinic, Professor
Project Period (FY)	2012-04-01 – 2014-03-31
Keywords	比較ゲノム / 遺伝子欠失 / 偽遺伝子化 / 無胃魚
Outline of Final Research Achievements	Certain lineages of teleost fish lack the stomach and are called agastric or stomachless fish, and four gastric genes, atp4a, atp4b, pgc, and pga2, have been co-deleted in stomachless fish. To better understand the genotypic convergence among agastric fishes, we compared open genome databases of agastric fishes (pufferfish, zebrafish, etc.) and gastric fishes (stickleback, etc.). Four genes involved in gastric function (kcne2, slc26a9, vsig1, cldn18a) were newly found to be frequently absent or pseudogenized in agastric fish genome databases. We also found that kcne2 and vsig1 were also absent or pseudogenized in the agastric monotremes echidna and platypus, respectively. These results revealed novel convergent gene losses at multiple loci among the major groups of agastric fishes, as well as a single gene loss in the echidna and platypus.
Free Research Field	複合新領域
Academic Significance and Societal Importance of the Research Achievements	器官の喪失という進化上の大きなイベントの仕組みを理解し、生物の生存戦略の違いや消化器の多様性を理解することは、生物多様性のより深い理解や、種の保全、養殖技術の開発などに貢献することが期待される。また、無胃魚で欠失していた遺伝子の一部が胃を退化させた哺乳類でも欠失していたことから、今後これらの遺伝子の解析を通して胃の形成にかかわる未知のメカニズムを解明することができれば、哺乳類における胃の研究や医学にも貢献できる可能性がある。