Accurate population genetic measurements require cryptic species identification in corals
Accurate population genetic measurements require cryptic species identification in corals
复制标题
准确的种群遗传测量需要珊瑚中的神秘物种鉴定
作者：
Elizabeth A. Sheets;Patricia A. Warner;S. Palumbi
正确识别密切相关的物种对于可靠地衡量基因流动是很重要的。错误地将不同物种的个体归类在一起被证明高估或低估了种群分化，但在经验数据集中观察到这些不同结果时，突出这些不同结果的例子很少。利用199个单核苷酸多态性，我们将风信子顶孢子虫和环孢子虫形态种复合体中的768个个体分别分配给先前发现的8个隐蔽遗传物种，并测量了三个地理尺度(礁内、岛礁间和太平洋群岛之间)的种内遗传分化。然后，我们将这些计算与每个尺度上估计的遗传分化进行比较，所有神秘的遗传物种混合在一起，就好像我们无法区分它们一样。在珊瑚礁尺度上，正确的遗传物种识别产生了比物种混合时更低的FST估计和更少的显著比较，从而提高了对短期基因流动的估计。相比之下，在大空间尺度上正确的遗传物种识别产生了比混合物种比较更高的FST测量结果，从而降低了对群岛之间长期基因流动的估计。对已发表的珊瑚种群遗传学研究进行的荟萃分析发现了类似的结果：在小空间尺度上的FST估计较低，在控制神秘物种的研究中也较少发现有意义的研究。我们的结果和这些控制神秘物种的先前数据集表明，当地珊瑚礁之间的遗传分化可能低于文献中通常报道的水平。没有适当地控制隐蔽的物种结构可能会在空间尺度上使种群遗传分析在不同方向上产生偏差，这对依赖这些估计的保护策略具有重要意义。
Correct identification of closely related species is important for reliable measures of gene flow. Incorrectly lumping individuals of different species together has been shown to over- or underestimate population differentiation, but examples highlighting when these different results are observed in empirical datasets are rare. Using 199 single nucleotide polymorphisms, we assigned 768 individuals in the Acropora hyacinthus and A. cytherea morphospecies complexes to each of eight previously identified cryptic genetic species and measured intraspecific genetic differentiation across three geographic scales (within reefs, among reefs within an archipelago, and among Pacific archipelagos). We then compared these calculations to estimated genetic differentiation at each scale with all cryptic genetic species mixed as if we could not tell them apart. At the reef scale, correct genetic species identification yielded lower FST estimates and fewer significant comparisons than when species were mixed, raising estimates of short-scale gene flow. In contrast, correct genetic species identification at large spatial scales yielded higher FST measurements than mixed-species comparisons, lowering estimates of long-term gene flow among archipelagos. A meta-analysis of published population genetic studies in corals found similar results: FST estimates at small spatial scales were lower and significance was found less often in studies that controlled for cryptic species. Our results and these prior datasets controlling for cryptic species suggest that genetic differentiation among local reefs may be lower than what has generally been reported in the literature. Not properly controlling for cryptic species structure can bias population genetic analyses in different directions across spatial scales, and this has important implications for conservation strategies that rely on these estimates.