Data from: Restriction to large-scale gene flow versus regional panmixia among cold seep Escarpia spp. (Polychaeta, Siboglinidae)

The history of colonization and dispersal in fauna distributed among deep-sea chemosynthetic ecosystems remains enigmatic and poorly understood because of an inability to mark and track individuals. A combination of molecular, morphological and environmental data improves understanding of spatial and temporal scales at which panmixia, disruption of gene flow or even speciation may occur. Vestimentiferan tubeworms of the genus Escarpia are important components of deep -sea cold seep ecosystems, as they provide long-term habitat for many other taxa. Three species of Escarpia, Escarpia spicata [Gulf of California (GoC)], Escarpia laminata [Gulf of Mexico (GoM)] and Escarpia southwardae (West African Cold Seeps), have been described based on morphology, but are not discriminated through the use of mitochondrial markers (cytochrome oxidase subunit 1; large ribosomal subunit rDNA, 16S; cytochrome b). Here, we also sequenced the exon-primed intron-crossing Haemoglobin subunit B2 intron and genotyped 28 microsatellites to (i) determine the level of genetic differentiation, if any, among the three geographically separated entities and (ii) identify possible population structure at the regional scale within the GoM and West Africa. Results at the global scale support the occurrence of three genetically distinct groups. At the regional scale among eight sampling sites of E. laminata (n = 129) and among three sampling sites of E. southwardae (n = 80), no population structure was detected. These findings suggest that despite the patchiness and isolation of seep habitats, connectivity is high on regional scales.深海化能合成生态系统（deep-sea chemosynthetic ecosystems）中分布的动物群的定殖与扩散历史，因无法对个体进行标记与追踪，至今仍神秘难解且认知匮乏。结合分子、形态与环境数据，有助于我们理解泛交（panmixia）、基因流中断甚至物种形成（speciation）可能发生的时空尺度。 脊管虫属（Escarpia）的管栖蠕虫（vestimentiferan tubeworms）是深海冷泉生态系统的重要组成类群，可为众多其他生物类群提供长期栖息生境。目前基于形态学特征已描述了3种脊管虫：尖脊管虫（Escarpia spicata，分布于加利福尼亚湾（GoC））、层纹脊管虫（Escarpia laminata，分布于墨西哥湾（GoM））以及南氏脊管虫（Escarpia southwardae，分布于西非冷泉区），但通过线粒体标记（包括细胞色素氧化酶亚基1（cytochrome oxidase subunit 1）、16S核糖体大亚基rDNA（large ribosomal subunit rDNA, 16S）以及细胞色素b（cytochrome b））无法对其进行区分。 本研究对外显子引物跨内含子（exon-primed intron-crossing）标记的血红蛋白亚基B2内含子进行了测序，并对28个微卫星（microsatellites）位点开展基因分型，旨在达成两个研究目标：(i) 明确这3个地理隔离类群之间是否存在遗传分化及其程度；(ii) 解析墨西哥湾与西非区域内的种群结构特征。 全球尺度的分析结果支持这3个遗传分化群体的存在。在区域尺度上，对层纹脊管虫的8个采样点（n=129）以及南氏脊管虫的3个采样点（n=80）的分析均未检测到种群结构。 上述研究结果表明，尽管冷泉生境存在斑块化分布与隔离性特征，但区域尺度上的种群连通性仍较高。