Data from: Microsatellite evidence for high frequency of multiple paternity in the marine gastropod Rapana venosa

Background: Inferring of parentage in natural populations is important in understanding the mating systems of a species, which have great effects on its genetic structure and evolution. Muricidae, a large group (approximately 1,600 species) of marine gastropods, are poorly investigated in patterns of multiple paternity and sperm competition based on molecular techniques. The veined Rapa whelk, Rapana venosa, a commercially important muricid species with internal fertilization, is an ideal species to study the occurrence and frequency of multiple paternity and to facilitate understanding of their reproductive strategies. Methodology/Principal Findings: We developed five highly polymorphic microsatellites in R. venosa and applied them to identify multiple paternity in 19 broods (1381 embryos) collected from Dandong, China. Multiple paternity was detected in 17 (89.5%) of 19 broods. The number of sires per brood ranged from 1 to 7 (4.3 on average). Of the 17 multiply sired broods, 16 (94.1%) were significantly skewed from equal paternal contributions, and had a dominant sire which was also dominant in each assayed capsule. Conclusions: Our results indicate that a high level of multiple paternity occurs in the wild population of R. venosa. Similar patterns of multiple paternity in the 2–6 assayed capsules from each brood imply that fertilization events within the body of a female occur mostly (but not entirely) as random draws from a “well-but-not-perfectly blended sperm pool” of her several mates. Strongly skewed distributions of fertilization success among sires also suggest that sperm competition and/or cryptic female choice might be important for post-copulatory paternity biasing in this species.研究背景：对自然种群开展亲权推断（parentage inference），对于解析物种的交配系统至关重要，而交配系统对物种的遗传结构与演化进程具有关键影响。骨螺科（Muricidae）是一类包含约1600个物种的大型海洋腹足类类群，但目前基于分子技术对其多父本交配（multiple paternity）模式与精子竞争（sperm competition）的研究仍较为匮乏。红皱岩螺（Rapana venosa）作为具有重要经济价值的体内受精骨螺科物种，是探究多父本交配的发生频率、并深入理解其繁殖策略的理想研究对象。 研究方法与主要结果：本研究开发了5个多态性极高的红皱岩螺微卫星（microsatellites）标记，并利用这些标记对中国丹东海域采集的19个育幼群（共1381枚胚胎）进行了多父本交配鉴定。结果显示，19个育幼群中有17个（占比89.5%）检测到多父本交配现象；单个育幼群的父本数量介于1至7之间，平均为4.3个。在17个存在多父本交配的育幼群中，16个（占比94.1%）的父本贡献显著偏离均等模式，且存在一个优势父本，该优势父本在所有检测的卵囊（capsule）中均占据主导地位。 研究结论：本研究结果表明，红皱岩螺野生种群中存在较高水平的多父本交配现象。对每个育幼群的2至6个卵囊进行检测后发现其多父本交配模式具有一致性，这意味着雌性体内的受精过程主要（但并非完全）是从其多个配偶的“混合充分但并非完全均匀的精子库”中进行随机抽取。父本间受精成功率呈现显著偏斜的分布模式，同样提示精子竞争和/或隐蔽雌性选择（cryptic female choice），可能是该物种交配后亲权偏向调控的重要机制。