Population genomics of two congeneric flatfish species having contrasting egg traits

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06202
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: Tohoku University
• Principal Investigator: Ikeda Minoru 東北大学, 農学研究科, 教授 (70232204)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: マコガレイ / マガレイ / 卵形質 / 粘着沈性卵 / 分離浮性卵 / ミトコンドリアDNA / RAD-Seq / 集団ゲノミクス

Outline of Final Research Achievements

Although marbled and yellow striped flounders belong to the same genus, the two species exhibit contrasting egg traits: adhesive demersal eggs in the former and isolated pelagic eggs in the latter. This difference in egg traits should be reflected in the population genetic structure within the species. To examine this prediction, population genomic analyses were conducted on both species sample populations collected from the coast of Japan. The mitogenomic analysis revealed that highly genetic differentiation occurred among marbled flounder populations, divided into seven local groups. In contrast, the populations of yellow striped flounder were homogeneous. The results of RAD-Seq analysis using more than 20,000 SNPs in the nuclear genome were consistent with those of the mitogenomic analysis, aside from the detection of weak differentiation among the yellow striped populations. These results support the prediction that differences in egg traits affect the genetic population structure.

Free Research Field

水産遺伝学

Academic Significance and Societal Importance of the Research Achievements

本研究は、同属ではあるが、粘着沈性卵を産むマコガレイと分離浮性卵を産むマガレイについて集団ゲノミクス解析（核DNAにおける大量のSNPs分析とミトコンドリアDNA分析）を行なった。その結果、マコガレイでは海域ごとに著しい遺伝的分化が認められ、7グループに分かれた。一方、マガレイではSNPs分析で微弱な遺伝的分化が検出されはしたもののほぼ均質であった。これらの結果は、卵形質の差異が集団構造に影響するという予測を支持するものであり、両種の資源管理に関して有用な情報を提示する。また、両種の参照ゲノム配列を構築中であり、卵形質の多様化に関する遺伝的基盤を探索する準備が整えられつつある。