Swept away: ocean currents and seascape features influence genetic structure across the 18,000 Km Indo-Pacific distribution of a marine invertebrate, the black-lip pearl oyster Pinctada margaritifera.
Swept away: ocean currents and seascape features influence genetic structure across the 18,000 Km Indo-Pacific distribution of a marine invertebrate, the black-lip pearl oyster Pinctada margaritifera.
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DOI：
10.1186/s12864-016-3410-y
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发表时间：
2017-01-10
期刊：
影响因子：
4.4
通讯作者：
Zenger KR
中科院分区：
文献类型：
--
作者：
Lal MM;Southgate PC;Jerry DR;Bosserelle C;Zenger KR
许多分布广泛的广播产卵海洋无脊椎动物的遗传结构仍然知之甚少，这对它们的渔业管理、养护和水产养殖构成了重大挑战。在核心-外围假说（CPH）下，遗传多样性在物种分布的中心处最高，随着种群变得越来越孤立、碎片化和局部适应，遗传多样性将随着向外范围界限分化的增加而逐渐降低。许多海洋无脊椎动物的独特生活史特征，如高分散率、随机生存和可变招募，也可能影响种群的组织方式。为了研究影响这种高度分散的双壳类动物种群结构、连通性和适应性变化的微观进化力量，研究了分布在印度-太平洋地区约1.8万公里的黑唇珍珠贝种群。利用9,624个全基因组snp和580只牡蛎进行的分析发现，在印度和太平洋盆地之间存在着显著和大量的大范围遗传结构的不同模式。与太平洋牡蛎种群相比，印度洋种群差异显著（F st = 0.2534-0.4177, p < 0.001），太平洋牡蛎种群在整个盆地范围内的基因流动要高得多（F st = 0.0007-0.1090, p < 0.001）。遗传多样性划分（分层AMOVA）对海洋盆地间差异的贡献率为18.1%，而对样本和种群间差异的贡献率更大（分别为45.8%和35.7%）。在选择性中性位点上的种群结构可视化分别解决了印度洋和太平洋的3个和5个离散遗传簇。对太平洋种群（定向选择下的89个snp， fst = 0.1012-0.4371, FDR = 0.05）适应性位点的遗传结构进行评估，发现了5个与中性snp检测结果相同的聚类，表明太平洋种群内部存在环境异质性。Mantel距离隔离试验（IBD）和独立流体动力粒子扩散模拟支持了结构和连通性的模式。研究结果表明，柽柳的遗传结构和连通性是高度复杂的，在大尺度上受洋流、IBD和海景特征的共同作用，以及区域层面的栖息地地貌和局部适应的共同作用。总体种群组织比一般CPH预测要复杂得多，然而对区域渔业管理有价值的见解，并且对高度分散的海洋无脊椎动物的遗传结构有了更深入的了解。本文的在线版本（doi:10.1186/s12864-016-3410-y）包含补充材料，可供授权用户使用。
Genetic structure in many widely-distributed broadcast spawning marine invertebrates remains poorly understood, posing substantial challenges for their fishery management, conservation and aquaculture. Under the Core-Periphery Hypothesis (CPH), genetic diversity is expected to be highest at the centre of a species’ distribution, progressively decreasing with increased differentiation towards outer range limits, as populations become increasingly isolated, fragmented and locally adapted. The unique life history characteristics of many marine invertebrates such as high dispersal rates, stochastic survival and variable recruitment are also likely to influence how populations are organised. To examine the microevolutionary forces influencing population structure, connectivity and adaptive variation in a highly-dispersive bivalve, populations of the black-lip pearl oyster Pinctada margaritifera were examined across its ~18,000 km Indo-Pacific distribution. Analyses utilising 9,624 genome-wide SNPs and 580 oysters, discovered differing patterns of significant and substantial broad-scale genetic structure between the Indian and Pacific Ocean basins. Indian Ocean populations were markedly divergent (F st = 0.2534–0.4177, p < 0.001), compared to Pacific Ocean oysters, where basin-wide gene flow was much higher (F st = 0.0007–0.1090, p < 0.001). Partitioning of genetic diversity (hierarchical AMOVA) attributed 18.1% of variance between ocean basins, whereas greater proportions were resolved within samples and populations (45.8% and 35.7% respectively). Visualisation of population structure at selectively neutral loci resolved three and five discrete genetic clusters for the Indian and Pacific Oceans respectively. Evaluation of genetic structure at adaptive loci for Pacific populations (89 SNPs under directional selection; F st = 0.1012–0.4371, FDR = 0.05), revealed five clusters identical to those detected at neutral SNPs, suggesting environmental heterogeneity within the Pacific. Patterns of structure and connectivity were supported by Mantel tests of isolation by distance (IBD) and independent hydrodynamic particle dispersal simulations. It is evident that genetic structure and connectivity across the natural range of P. margaritifera is highly complex, and produced by the interaction of ocean currents, IBD and seascape features at a broad scale, together with habitat geomorphology and local adaptation at regional levels. Overall population organisation is far more elaborate than generalised CPH predictions, however valuable insights for regional fishery management, and a greater understanding of range-wide genetic structure in a highly-dispersive marine invertebrate have been gained. The online version of this article (doi:10.1186/s12864-016-3410-y) contains supplementary material, which is available to authorized users.