Data from: Clones or clans: the genetic structure of a deep-sea sponge, Aphrocallistes vastus, in unique sponge reefs of British Columbia, Canada

Understanding patterns of reproduction, dispersal and recruitment in deep-sea communities is increasingly important with the need to manage resource extraction and conserve species diversity. Glass sponges are usually found in deep water (>1000 m) worldwide but form kilometre-long reefs on the continental shelf of British Columbia and Alaska that are under threat from trawling and resource exploration. Due to their deep-water habitat, larvae have not yet been found and the level of genetic connectivity between reefs and nonreef communities is unknown. The genetic structure of Aphrocallistes vastus, the primary reef-building species in the Strait of Georgia (SoG) British Columbia, was studied using single nucleotide polymorphisms (SNPs). Pairwise comparisons of multilocus genotypes were used to assess whether sexual reproduction is common. Structure was examined 1) between individuals in reefs, 2) between reefs and 3) between sites in and outside the SoG. Sixty-seven SNPs were genotyped in 91 samples from areas in and around the SoG, including four sponge reefs and nearby nonreef sites. The results show that sponge reefs are formed through sexual reproduction. Within a reef and across the SoG basin, the genetic distance between individuals does not vary with geographic distance (r = −0.005 to 0.014), but populations within the SoG basin are genetically distinct from populations in Barkley Sound, on the west coast of Vancouver Island. Population structure was seen across all sample sites (global FST = 0.248), especially between SoG and non-SoG locations (average pairwise FST = 0.251). Our results suggest that genetic mixing occurs across sponge reefs via larvae that disperse widely.

随着资源开发管理与物种多样性保护需求的日益提升，解析深海群落的繁殖、扩散与种群补充模式的重要性愈发凸显。玻璃海绵（glass sponges）通常广泛分布于全球水深＞1000米的深水海域，但在不列颠哥伦比亚省与阿拉斯加的大陆架上形成了长达数公里的礁体，这些礁体正面临拖网捕捞与资源勘探的双重威胁。由于其栖息于深水环境，学界迄今尚未发现该物种的幼体，且各礁体与非礁群落间的遗传连通水平仍属未知。本研究采用单核苷酸多态性（single nucleotide polymorphisms, SNPs）标记，对不列颠哥伦比亚省乔治亚海峡（Strait of Georgia, SoG）的主要造礁物种*Aphrocallistes vastus*的遗传结构展开研究：通过多位点基因型的两两比对，评估有性繁殖是否为该物种的常见繁殖方式；并从三个维度解析种群遗传结构，分别为1）礁体内部个体间的遗传结构、2）不同礁体间的遗传结构，以及3）乔治亚海峡内外各采样点间的遗传结构。研究人员对采自乔治亚海峡及其周边区域的91份样本进行了基因分型，共获得67个有效SNPs位点，采样范围涵盖4处玻璃海绵礁体及其邻近的非礁采样点。研究结果表明，玻璃海绵礁体是通过有性繁殖过程形成的。在单个礁体内部以及乔治亚海峡盆地区域内，个体间的遗传距离与地理距离并无显著相关性（相关系数r=-0.005~0.014）；但乔治亚海峡盆地区域内的种群，与温哥华岛西海岸巴克利湾（Barkley Sound）的种群存在显著遗传分化。所有采样点均呈现出明显的种群遗传结构（整体固定指数FST=0.248），其中尤以乔治亚海峡内外采样点间的分化最为显著，平均两两固定指数为0.251。本研究结果表明，广泛扩散的幼体使得不同玻璃海绵礁体间发生了充分的遗传混合。