Divergent northern and southern populations and demographic history of the pearl oyster in the western Pacific revealed with genomic SNPs
Divergent northern and southern populations and demographic history of the pearl oyster in the western Pacific revealed with genomic SNPs
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DOI：
10.1111/eva.12905
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发表时间：
2020-01-08
影响因子：
4.1
通讯作者：
Satoh, Noriyuki
中科院分区：
文献类型：
--
作者：
Takeuchi, Takeshi;Masaoka, Tetsuji;Satoh, Noriyuki
在没有地形边界的开阔海洋中，具有浮游幼虫的海洋无脊椎动物可以利用洋流进行长距离迁移，这表明遗传多样性减少。然而，与这一假设相反，在海洋无脊椎动物中经常观察到遗传分化。在本研究中，我们试图解释种群结构是如何建立在西太平洋，在那里强大的黑潮电流保持高水平的基因流从南到北，大概促进遗传同质性。我们确定了人口结构的珍珠牡蛎，合浦珠母贝，在印度-太平洋使用全基因组基因分型数据从多个采样地点。聚类分析表明，西太平洋种群与印度洋种群不同，分为北方（日本大陆）和南方（南西群岛、中国和柬埔寨）种群。合浦珠母贝的遗传分化可以用印度洋和当地泻湖的地理屏障以及西太平洋的海表温度和氧浓度的环境梯度来解释。基因组扫描显示了基因组位点适应性进化的证据，可能与环境因素的变化有关，包括SST和氧浓度。此外，贝叶斯模拟表明，过去的人口扩张和分裂与末次冰期后的海洋变暖是一致的。环境梯度很可能形成了西太平洋合浦珊瑚种群多样化的遗传屏障。这一假说有助于解释海洋无脊椎动物的遗传分化和可能的物种形成。
In the open ocean without terrain boundaries, marine invertebrates with pelagic larvae can migrate long distances using ocean currents, suggesting reduced genetic diversification. Contrary to this assumption, however, genetic differentiation is often observed in marine invertebrates. In the present study, we sought to explain how population structure is established in the western Pacific Ocean, where the strong Kuroshio Current maintains high levels of gene flow from south to north, presumably promoting genetic homogeneity. We determined the population structure of the pearl oyster, Pinctada fucata, in the Indo-Pacific Ocean using genome-wide genotyping data from multiple sampling localities. Cluster analysis showed that the western Pacific population is distinct from that of the Indian Ocean, and that it is divided into northern (Japanese mainland) and southern (Nansei Islands, China, and Cambodia) populations. Genetic differentiation of P. fucata can be explained by geographic barriers in the Indian Ocean and a local lagoon, and by environmental gradients of sea surface temperature (SST) and oxygen concentration in the western Pacific. A genome scan showed evidence of adaptive evolution in genomic loci, possibly associated with changes in environmental factors, including SST and oxygen concentration. Furthermore, Bayesian simulation demonstrated that the past population expansion and division are congruent with ocean warming after the last glacial period. It is highly likely that the environmental gradient forms a genetic barrier that diversifies P. fucata populations in the western Pacific. This hypothesis helps to explain genetic differentiation and possible speciation of marine invertebrates.