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.