CSIRO Oceans & Atmosphere, Castray Esplanade, Battery Point, Hobart, TAS 7004, Australia.
CSIRO Australian National Fish Collection, National Research Collections Australia, Castray Esplanade, Hobart, TAS 7004, Australia.
Sci Rep. 2017 May 8;7(1):1528. doi: 10.1038/s41598-017-01416-w.
This study assessed the presence and prevalence of multiple paternity (MP) in litters of grey reef sharks (Carcharhinus amblyrhynchos) and scalloped hammerheads (Sphyrna lewini) opportunistically caught in Papua New Guinea (PNG). Litter size between species were significantly different with an average of 3.3 pups for grey reef sharks and 17.2 pups for scalloped hammerhead. Using 14 and 10 microsatellite loci respectively, we identified MP in 66% of grey reef sharks (4 out of 6 litters) and 100% MP in scalloped hammerheads (5 litters). We found high paternal skew (the uneven contribution of sires per litter) and a positive correlation between female adult size and litter size in scalloped hammerheads but not in grey reef sharks. Differences in the frequency of MP between species and the identification of paternal skew may be linked with mating strategies and post-copulatory mechanisms. Multiple paternity is thought to benefit populations by enhancing genetic diversity therefore increasing the population's genetic resilience to extrinsic pressures. The identification of MP in two shark species reported here, further elucidates the complex breeding strategies elasmobranchs undertake.
本研究评估了在巴布亚新几内亚（PNG）偶然捕获的灰礁鲨（Carcharhinus amblyrhynchos）和皱唇鲨（Sphyrna lewini）的窝仔中存在和普遍存在的多父本（MP）现象。物种之间的窝仔大小差异显著，灰礁鲨的平均窝仔数为 3.3 只，皱唇鲨的平均窝仔数为 17.2 只。分别使用 14 个和 10 个微卫星基因座，我们在 66%的灰礁鲨窝仔（6 窝中的 4 窝）和 100%的皱唇鲨窝仔（5 窝）中发现了多父本现象。我们发现，皱唇鲨的父本偏斜度较高（每窝父亲的贡献不均等），并且雌性成年体型与窝仔大小之间呈正相关，但灰礁鲨则没有这种现象。物种间多父本现象的频率差异以及父本偏斜的鉴定可能与交配策略和交配后机制有关。多父本被认为通过增加遗传多样性从而提高种群对外部压力的遗传弹性，从而使种群受益。本研究报告了两种鲨鱼中多父本现象的鉴定，进一步阐明了鲨鱼采取的复杂繁殖策略。
