Data from: Consequences of a poecilogonous life history for genetic structure in coastal populations of the polychaete Streblospio benedicti

In many species, alternative developmental pathways lead to the production of two distinct phenotypes, promoting the evolution of morphological novelty and diversification. Offspring type in marine invertebrates influences transport time by ocean currents, which dictate dispersal potential and gene flow, and thus has sweeping evolutionary effects on the potential for local adaptation and on rates of speciation, extinction, and molecular evolution. Here we use the polychaete Streblospio benedicti to investigate the effects of dimorphic offspring type on gene flow and genetic structure in coastal populations. We use 84 single nucleotide polymorphism (SNP) markers for this species to assay populations on the East and West Coasts of the United States. Using these markers we found that in their native East Coast distribution, populations of S. benedicti have high population genetic structure, but this structure is associated primarily with geographic separation rather than developmental differences. Interestingly, very little genetic differentiation is recovered between individuals of different development types when they occur in the same or nearby populations, further supporting that this is a true case of poecilogony. In addition, we were able to demonstrate that the recently introduced West Coast populations (~100ya) likely originated from a lecithotrophic population near Delaware.在众多物种中，差异化发育途径可产生两种截然不同的表型，进而推动形态学创新与物种分化的演化进程。海洋无脊椎动物的子代发育类型会影响洋流的运输时长，而该时长决定了物种的扩散潜力与基因流（gene flow），因此对局部适应潜力、物种形成、灭绝以及分子演化的速率均具有广泛的演化影响。本研究以多毛类（polychaete）物种*Streblospio benedicti*为研究对象，探究双态子代发育类型对海岸种群基因流与遗传结构的影响。本研究利用针对该物种开发的84个单核苷酸多态性（single nucleotide polymorphism, SNP）标记，对美国东西海岸的种群开展遗传检测。结果显示，在其自然分布的美国东海岸区域，*S. benedicti*种群具有较高的群体遗传结构，但该结构主要与地理隔离相关，而非发育类型差异。值得注意的是，当不同发育类型的个体栖息于同一或邻近种群时，二者之间几乎未检测到遗传分化，这进一步证实该现象属于真正的多型发育（poecilogony）。此外，本研究证实，近期引入的美国西海岸种群（约100年历史）大概率起源于特拉华州附近的卵黄营养型（lecithotrophic）种群。