2022 Fiscal Year Final Research Report
Comparative study on intraspecieis diversities of sex determination systems in Japanese geckos
Project/Area Number |
20K06790
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 45030:Biodiversity and systematics-related
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Research Institution | Chubu University |
Principal Investigator |
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 性染色体 / 温度依存性決定 / ヤモリ / 進化 / 種内多様性 / DMRT1 |
Outline of Final Research Achievements |
To infer the evolutionary process of the sex chromosomes and sex determination systems, I investigate diversities of sex chromosomes in Hokou gecko and Japanese gecko. Contigs that includes Z and W homologs of DMRT1 were screened from draft genome sequence of a female from Okinawa strain. By comparison of nucleotide sequences of these contigs, W chromosome specific sequences were identified on downstream of DMRT1. As these sequences were also identified in Ishigaki strain, differentiation of Z and W homologs initiated in the common ancestor between Okinawa and Ishigaki strains. This suggests that an initial step of sex chromosome differentiation was allelic differentiation of DMRT1 (a sex determining gene in Vertebrate) in the common ancestor of two strains. On the contrary, the common W chromosome specific sequences were not detected in North Tokara and South Kyushu strains. This suggests that sex chromosomes of the two strains have independently evolved.
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Free Research Field |
細胞遺伝学
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Academic Significance and Societal Importance of the Research Achievements |
ミナミヤモリ4系統の性染色体の比較解析から、沖縄島系統と石垣島系統の性染色体は共通祖先に端を発し、一方で北トカラ系統と南九州系統では独自に性染色体の進化が起きたと推定された。この様に、島嶼など小さな隔離地域に生息する個体群では独自の性染色体の進化や生物学的特徴の獲得が起きている可能性があり、これら隔離個体群の調査や保護の重要性が示された。ミナミヤモリ沖縄島系統と石垣島系統の性染色体の分化の開始には、脊椎動物の性分化関連遺伝子であるDMRT1の対立遺伝子間での分化が切掛となったことが改めて示唆された。この事は、性染色体の誕生には性分化関連遺伝子の収斂進化といった共通原理があることを支持する。
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