Alternative Titleブリ類のゲノム染色体進化と性決定様式の獲得に関する研究
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Fishes are the vertebrate group which appeared first on the earth and are the most diverse taxon in many aspects of evolution. This high level of biodiversity is a powerful basis for studying genome evolution. In this study, genome structures and correlations between genetic variation and phenotype of greater amberjack (Seriola dumerili) were investigated. The amberjacks are economically very important, and its ecology is much different from model fish species such as Japanese medaka (Oryzias latipes) and zebrafish (Danio rerio). Therefore, the knowledge of amberjack genome is invaluable in terms of aquaculture and understanding fish genome evolution. To investigate chromosome evolution in fish species, newly 181 markers were mapped, which allowed the construction of yellowtail radiation hybrid (RH) physical map with 1,713 DNA markers, which was much denser than a previous map, and the de novo assembled sequences were anchored onto the RH physical map. Finally, a total of 13,977 expressed sequence tags (ESTs) were mapped on a genome sequence assembly aligned with the physical map. Using the high-density physical map and anchored genome sequences, the yellowtail genome structure was compared in detail with those of five model fishes to characterize the yellowtail genome. Between yellowtail and Japanese medaka, almost all regions of the chromosomes were conserved and some blocks comprising several markers were translocated. Using the genome information of the spotted gar (Lepisosteus oculatus) as a reference, syntenic relationships and chromosomal rearrangements that occurred during evolution in four other acanthopterygian species (Japanese medaka, zebrafish, spotted green pufferfish (Tetraodon nigroviridis) and three-spined stickleback (Gasterosteus aculeatus)) were documented. The evolutionary chromosome translocation frequency was 1.5–2 times higher in yellowtail than in medaka, pufferfish, and stickleback. Sex determination system of fish is highly diverse compared with that of mammal. Thus, investigations using nonmodel fish species helps the understanding of sex determination systems of fish. In this study, sex-associated SNPs of greater amberjack were identified using SNP information of 10 males and 10 females by an association test. Sex-associated SNPs were detected on chromosome 12 and mainly covered with two scaffolds, c168 and c43. Genotypes of sex-associated SNPs indicated that greater amberjack has female heterogametic sex determination system (ZZ/ZW). Furthermore, the genomic structure of greater amberjack was compared with those of yellowtail and Japanese medaka. Whole genome alignment and synteny analysis indicated that sex determination system of greater amberjack is markedly different from that of medaka and inferred that the sex determination region on chromosome 12 is conserved in the Seriola species.
本文 / Graduate School of Bioresources Mie University
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Collection (particular)国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
Date Accepted (W3CDTF)2019-05-06T10:27:56+09:00
Data Provider (Database)国立国会図書館 : 国立国会図書館デジタルコレクション