Evolutionary effects of geographic and climatic isolation between Rhododendron tsusiophyllum populations on the Izu Islands and mainland Honshu of Japan
Evolutionary effects of geographic and climatic isolation between Rhododendron tsusiophyllum populations on the Izu Islands and mainland Honshu of Japan
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DOI：
10.1038/s41437-021-00417-w
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发表时间：
2021-03
期刊：
影响因子：
3.8
通讯作者：
Watanabe Yoichi;M. Takahashi;A. Nagano;K. Uehara;Harue Abe
中科院分区：
文献类型：
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作者：
Watanabe Yoichi;M. Takahashi;A. Nagano;K. Uehara;Harue Abe
岛屿和大陆的地理和环境隔离为调查岛屿人口的殖民化和生存动态提供了极好的机会。我们推断并比较了伊豆群岛和本州岛（这里被视为大陆）上的杜鹃花（rhododendron tsusiophyllum）的进化过程和人口历史，使用了从8个r种群中通过ddRAD-seq获得的数千个核snp。木犀草和三居群。schonoskiia是一个外群体。系统发育关系及其栖息地表明r。木藻从寒冷的北方向温暖的南方进化和迁移。我们在本州岛和伊豆岛三个地区的种群中发现了明显的遗传差异，这表明它们之间的迁徙受到限制，因为它们在大陆上的栖息地是孤立的。三个地区的有效种群规模变化不同，特别是伊豆群岛的遗传多样性和种群规模相对较小。此外，伊豆群岛的种群栖息地比本州温暖，表明它们经历了适应性进化。我们的研究提供了山地隔离而非岛屿隔离对种群遗传分化、种群生存和适应性进化意义的证据，这些岛屿种群规模小，遗传多样性低，尽管与大陆种群接近。
Geographic and environmental isolations of islands and the mainland offer excellent opportunity to investigate colonization and survival dynamics of island populations. We inferred and compared evolutionary processes and the demographic history ofRhododendron tsusiophyllum, in the Izu Islands and the much larger island Honshu, treated here as the mainland, using thousands of nuclear SNPs obtained by ddRAD-seq from eight populations ofR. tsusiophyllumand three populations ofR. tschonoskiias an outgroup. Phylogenetic relationships and their habitats suggest thatR. tsusiophyllumhad evolved and migrated from cold north to warm south regions. We detected clear genetic divergence among populations in three regions of Honshu and the Izu Islands, suggesting restricted migration between them due to isolated habitats on mountains even in the mainland. The three regions have different changes in effective population size, especially, genetic diversity and population size of the Izu Islands are small compared to the others. Further, habitats of populations in the Izu Islands are warmer than those in Honshu, suggesting that they have undergone adaptive evolution. Our study provides evidences of montane rather than insular isolation on genetic divergence, survival of populations and significance of adaptive evolution for island populations with small population size and low genetic diversity, despite close proximity to mainland populations.