Convergent evolution of the seasonal coat-color change

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15862
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: National Institute of Genetics (2021-2022); Kyoto University (2020)
• Principal Investigator: Kinoshita Gohta 国立遺伝学研究所, ゲノム・進化研究系, 博士研究員 (60774578)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 季節性毛色変化 / 環境適応 / 野生哺乳類 / 収斂進化

Outline of Final Research Achievements

In this study, we were focusing on the causative genes for the two types of coat color in the Japanese hare, conducting the analysis of gene expression patterns, the origin of polymorphisms through phylogenetic analysis, and the population dynamics due to past climate changes. As a result, we detected differences in the expression levels during the autumn molting period associated with the alleles involved in the polymorphism. Furthermore, we revealed that both alleles are phylogenetically distant from the alleles associated with the polymorphism in hares in North America one of which also exhibit polymorphism caused by the same gene. Additionally, a dynamic increase and decrease in effective population size were estimated during the period around the last glacial maximum in the Japanese hare population in the archipelago.

Free Research Field

生態遺伝学

Academic Significance and Societal Importance of the Research Achievements

毛色や羽毛の冬季白化は積雪環境への適応形質として、温帯以北の様々な哺乳類や鳥類で収斂進化している。しかし、異なる分類群間でどのように冬季白化が収斂進化したのかは未解明な部分が大きい。本研究では、ニホンノウサギはこれまで報告されている大陸産ノウサギとは異なる遺伝的基盤により季節性毛色変化を収斂進化させたことを明らかにすることができた。同時にその起源として、祖先多型の可能性や、未解析種からの遺伝子浸透の可能性も示唆された。本研究の成果は、北方に生息する多様な哺乳類で季節適応の遺伝的基盤と、気候変動による生物の進化的応答についての重要な知見を与えるものである。