Linkage disequilibrium mapping using closely related species -Toward the identification of sex-determining gene in genus Seriola-

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K18741
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: The University of Tokyo
• Principal Investigator: Koyama Takashi 東京大学, 大学院農学生命科学研究科(農学部), 特任研究員 (40749701)
• Research Collaborator: NAKAMOTO Masatoshi 東京海洋大学, 学術研究院, 博士研究員 ; YAMASHIT Takefumi 東京大学, 先端科学技術研究センター, 特任准教授 ; MIZUNO Naoki 東京大学, 大学院農学生命科学研究科(農学部), 技術専門職員 ; TASUMI Satoshi 東京大学, 大学院農学生命科学研究科(農学部), 特任助教 ; HOSOYA Sho 東京大学, 大学院農学生命科学研究科(農学部), 助教 ; UNO Seiichi 鹿児島大学, 水産学部, 准教授 ; TOYODA Atsushi 国立遺伝学研究所, 生命情報研究センター, 特任教授 ; SAKAMOTO Takashi 東京海洋大学, 学術研究院, 教授 ; KIKUCHI Kiyoshi 東京大学, 大学院農学生命科学研究科(農学部), 准教授
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: ブリ属 / 性決定遺伝子 / ステロイド

Outline of Final Research Achievements

In this study, using genomic, genetic, biochemical, computational, and histological approaches, we found that a single-nucleotide polymorphism (SNP) in one of the steroidogenic enzyme genes, 17β-hydroxysteroid dehydrogenase 1 (Hsd17b1), is a genetic sex determiner in a ZZ/ZW sex determination system of two Seriola fishes. This sex-determining SNP causes a non-synonymous change from glycine on the W chromosome to glutamic acid on the Z near the catalytic center of Hsd17b1, which disrupts the hydrogen-bond network among steroids and the catalytic residues of the enzyme. Consequently, inter-conversion between 17-keto and 17β-hydroxy steroids is attenuated in the Z. Based on these results, we conclude that homozygosity for the Z allele results in testis formation due to the reduced enzymatic activity of its gene product and the resultant shortage of estradiol, whereas Z/W heterozygosity promotes the development of ovaries due to active W.

Free Research Field

魚類遺伝学