Yamasaki Yo Y, Takeshima Hirohiko, Kano Yuichi, Oseko Naoharu, Suzuki Toshiyuki, Nishida Mutsumi, Watanabe Katsutoshi
Graduate School of Science, Kyoto University, Sakyo, Kyoto, Japan.
Ecological Genetics Laboratory, Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, Japan.
Mol Ecol. 2020 Aug;29(16):3071-3084. doi: 10.1111/mec.15415. Epub 2020 Apr 19.
Predicting speciation is a fundamental goal of research in evolutionary ecology. The probability of speciation is often positively correlated with ecosystem size. Although the mechanisms driving this correlation are generally difficult to identify, a shared geographical and ecological context provides a suitable condition to study the mechanisms that promote speciation in large ecosystems by reducing the number of factors to be considered. Here, we determined the correlation between speciation and ecosystem size, and discuss the underlying mechanisms of this relationship, using a probable parallel ecotype formation for freshwater fish. Our population genetic analysis revealed that speciation of the landlocked goby, Rhinogobius sp. YB, of the Ryukyu Archipelago, Japan, from its migratory ancestor, R. brunneus, occurred in parallel across five islands. Logistic regression analysis showed that speciation probability could be predicted using island size. The results suggest that ecosystem size predicts the occurrence of adaptation and reproductive isolation, probably through its association with three possible factors: divergent selection strength, population persistence, and occurrence probability of habitat separation.
预测物种形成是进化生态学研究的一个基本目标。物种形成的概率通常与生态系统大小呈正相关。尽管驱动这种相关性的机制通常难以确定，但共享的地理和生态背景通过减少需要考虑的因素数量，为研究大型生态系统中促进物种形成的机制提供了合适的条件。在这里，我们利用淡水鱼可能的平行生态型形成，确定了物种形成与生态系统大小之间的相关性，并讨论了这种关系的潜在机制。我们的群体遗传分析表明，日本琉球群岛的内陆虾虎鱼（Rhinogobius sp. YB）与其洄游祖先褐吻虾虎鱼（R. brunneus）的物种形成在五个岛屿上平行发生。逻辑回归分析表明，物种形成概率可以用岛屿大小来预测。结果表明，生态系统大小可能通过与三个可能的因素相关联来预测适应和生殖隔离的发生：趋异选择强度、种群持久性和栖息地分离的发生概率。
