Data from: Population subdivision of hydrothermal vent polychaete Alvinella pompejana across equatorial and Easter Microplate boundaries

Background: The Equator and Easter Microplate regions of the eastern Pacific Ocean exhibit geomorphological and hydrological features that create barriers to dispersal for a number of animals associated with deep-sea hydrothermal vent habitats. This study examined effects of these boundaries on geographical subdivision of the vent polychaete Alvinella pompejana. DNA sequences from one mitochondrial and eleven nuclear genes were examined in samples collected from ten vent localities that comprise the species’ known range from 23°N latitude on the East Pacific Rise to 38°S latitude on the Pacific Antarctic Ridge. Results: Multi-locus genotypes inferred from these sequences clustered the individual worms into three metapopulation segments — the northern East Pacific Rise (NEPR), southern East Pacific Rise (SEPR), and northeastern Pacific Antarctic Ridge (PAR) — separated by the Equator and Easter Microplate boundaries. Genetic diversity estimators were negatively correlated with tectonic spreading rates. Application of the isolation-with-migration (IMa2) model provided information about divergence times and demographic parameters. The PAR and NEPR metapopulation segments were estimated to have split roughly 4.20 million years ago (Mya) (2.42–33.42 Mya, 95 % highest posterior density, (HPD)), followed by splitting of the SEPR and NEPR segments about 0.79 Mya (0.07–6.67 Mya, 95 % HPD). Estimates of gene flow between the neighboring regions were mostly low (2 Nm < 1). Estimates of effective population size decreased with southern latitudes: NEPR > SEPR > PAR. Conclusions: Highly effective dispersal capabilities allow A. pompejana to overcome the temporal instability and intermittent distribution of active hydrothermal vents in the eastern Pacific Ocean. Consequently, the species exhibits very high levels of genetic diversity compared with many co-distributed vent annelids and mollusks. Nonetheless, its levels of genetic diversity in partially isolated populations are inversely correlated with tectonic spreading rates. As for many other vent taxa, this pioneering colonizer is similarly affected by local rates of habitat turnover and by major dispersal filters associated with the Equator and the Easter Microplate region.

背景：东太平洋赤道与复活节微板块（Easter Microplate）区域拥有独特的地貌与水文特征，此类特征可对多种依附深海热液喷口生境（deep-sea hydrothermal vent habitats）生存的动物的扩散过程构成障碍。本研究以热液喷口多毛类动物庞贝蠕虫（Alvinella pompejana）为研究对象，探讨上述地理边界对其地理分化的影响。研究采集了覆盖该物种已知分布范围的10个喷口位点样本，其分布跨度从东太平洋海隆（East Pacific Rise）北纬23°延伸至太平洋南极脊（Pacific Antarctic Ridge）南纬38°，并对1个线粒体基因与11个核基因的DNA序列开展了分析。结果：基于上述序列推导得到的多位点基因型（multi-locus genotypes）可将个体蠕虫划分为3个集合种群（metapopulation）集群——北东太平洋海隆（NEPR）、南东太平洋海隆（SEPR）以及东北太平洋南极脊（PAR），各集群被赤道与复活节微板块边界相互分隔。遗传多样性估计值与构造扩张速率呈显著负相关关系。应用隔离与迁移模型（isolation-with-migration, IMa2）可获取分化时间与种群动态参数相关信息。经估计，PAR与NEPR集合种群集群的分化时间约为420万年前（95%最高后验密度（HPD）区间：242万~3342万年），随后SEPR与NEPR集群的分化时间约为79万年前（95%HPD区间：7万~667万年）。相邻区域间的基因流（gene flow）估计值普遍较低（2Nm < 1）。有效种群大小（effective population size）的估计值随南纬度升高呈递减趋势：NEPR > SEPR > PAR。结论：极强的扩散能力使得庞贝蠕虫能够克服东太平洋活跃热液喷口的时空不稳定性与间歇性分布特征。相较于诸多同分布区域的环节动物（annelids）与软体动物（mollusks），该物种展现出极高水平的遗传多样性。尽管如此，其在部分隔离种群中的遗传多样性水平仍与构造扩张速率呈负相关关系。与多数其他热液喷口类群一致，这种先驱拓殖者同样受到生境更替局部速率以及与赤道、复活节微板块区域相关的主要扩散过滤因子的影响。