Data from: Intraspecific genetic structure, divergence and high rates of clonality in an amphi-Atlantic starfish

Intraspecific genetic diversity and divergence have a large influence on the adaption and evolutionary potential of species. The widely distributed starfish, Coscinasterias tenuispina, combines sexual reproduction with asexual reproduction via fission. Here we analyse the phylogeography of this starfish to reveal historical and contemporary processes driving its intraspecific genetic divergence. We further consider whether asexual reproduction is the most important method of propagation throughout the distribution range of this species. Our study included 326 individuals from 16 populations, covering most of the species’ distribution range. A total of 12 nuclear microsatellite loci and sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene were analysed. COI and microsatellites were clustered in two isolated lineages: one found along the south-western Atlantic and the other along the north-eastern Atlantic and Mediterranean Sea. This suggests the existence of two different evolutionary units. Marine barriers along the European coast would be responsible for population clustering: the Almeria-Oran Front that limits the entrance of migrants from the Atlantic to the Mediterranean, and the Siculo Tunisian strait that divides the two Mediterranean basins. The presence of identical genotypes was detected in all populations, although two monoclonal populations where found in two sites where annual mean temperatures and minimum values were the lowest. Our results based on microsatellite loci showed that intra-population genetic diversity was significantly affected by clonality whereas it had lower effect for the global phylogeography of the species, although still some impact on populations’ genetic divergence could be observed between some populations.

种内遗传多样性与遗传分化对物种的适应性及进化潜力具有重要影响。广泛分布的海星物种——细刺多棘海星（Coscinasterias tenuispina）兼具有性生殖与分裂无性生殖两种繁殖方式。本研究通过解析该海星的系统地理学（phylogeography）格局，以揭示驱动其种内遗传分化的历史与当代过程。本研究进一步探讨无性生殖是否为该物种在整个分布范围内的主要繁殖策略。本研究共采集了覆盖该物种绝大多数分布范围的16个种群的326个个体。研究共分析了12个核微卫星位点（microsatellite loci）以及线粒体细胞色素c氧化酶亚基I（COI）基因序列。COI基因与微卫星位点均聚类为两个孤立支系：一支分布于西南大西洋海域，另一支分布于东北大西洋与地中海海域，这表明该物种存在两个不同的进化单元。欧洲沿岸的海洋屏障是导致种群聚类的关键因素：一是限制大西洋向地中海迁徙个体进入的阿尔梅里亚-奥兰海锋（Almeria-Oran Front），二是分隔地中海两个海盆的西西里-突尼斯海峡（Siculo Tunisian strait）。尽管在两个年均温与最低温均为最低的采样点发现了单克隆种群，但所有种群中均检测到了相同基因型的个体。基于微卫星位点的分析结果显示，克隆繁殖对种群内遗传多样性具有显著影响，尽管其对该物种整体系统地理学格局的影响相对较弱，但仍可观察到其对部分种群间遗传分化存在一定作用。