Population genomics of western Pacific abalones

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K19280
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Forestry and Forest Products Science, Applied aquatic science, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Hirase Shotaro 東京大学, 大学院農学生命科学研究科(農学部), 助教 (90635559)
• Co-Investigator(Kenkyū-buntansha): 關野 正志 国立研究開発法人水産研究・教育機構, 中央水産研究所, グループ長 (90371799)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: アワビ / 種分化 / 集団ゲノミクス / ゲノムシーケンス / GRAS-Di / 保全 / 生殖隔離

Outline of Final Research Achievements

A species complex of western Pacific abalones is classified into three putative species including two subspecies: H. discus discus (Kuro), H. d. hannai (Ezo), H. madaka (Madaka), and H. gigantia (Megai), and the Kuro, Madaka, and Megai show same distribution. Morphological and ecological characteristics suggested that Kuro/Ezo, Madaka, and Megai are distinct species, respectively, but they are genetically close and can produce viable F1 hybrids. We performed population genomic analyses for these species by whole genome resequencing and GRAS-Di. Phylogenetic and clustering analyses demonstrated clear genetic divergences among Ezo/Kuro, Madaka, Megai. Our analyses also detected allele sharing of nuclear genomes among species, and demographic modeling estimated that the evolution of their reproductive isolation has proceeded with gene flow. We identified genomic regions showing the signals of divergent selection between Ezo/Kuro and Madaka, which may be associated with speciation.

Free Research Field

水圏分子生態学

Academic Significance and Societal Importance of the Research Achievements

近縁であるにも関わらず、種の独自性を生みだしている遺伝基盤を明らかにすることは、対象となる生物種の増養殖及び保全戦略を考える上で重要であり、種分化のプロセスを考える上でも興味深い。本研究の成果は、日本の水産重要種であるエゾアワビ、クロアワビ、マダカアワビ、メガイアワビの保全方策を立案するための重要な遺伝情報を提供する。また、本研究をさらに深化させることで、海洋における種分化プロセスのモデルケースを提示できると考えている。