Selection and sex-biased dispersal in a coastal shark: the influence of philopatry on adaptive variation

Sex-biased dispersal is expected to homogenize nuclear genetic variation relative to variation in genetic material inherited through the philopatric sex. When site fidelity occurs across a heterogeneous environment, local selective regimes may alter this pattern. We assessed spatial patterns of variation in nuclear-encoded, single nucleotide polymorphisms (SNPs) and sequences of the mitochondrial control region in bonnethead sharks (Sphyrna tiburo), a species thought to exhibit female philopatry, collected from summer habitats used for gestation. Geographic patterns of mtDNA haplotypes and putatively neutral SNPs confirmed female philopatry and male-mediated gene flow along the northeastern coast of the Gulf of Mexico. A total of 30 outlier SNP loci were identified; alleles at over half of these loci exhibited signatures of latitude-associated selection. Our results indicate that in species with sex-biased dispersal, philopatry can facilitate sorting of locally adaptive variation, with ...

相较于通过留居性别传递的遗传物质变异，性别偏向性扩散（sex-biased dispersal）理论上会使核遗传变异趋于均一化。当异质环境中存在栖地忠实性时，局域选择机制或改变这一模式。我们对采集自双髻鲨（Sphyrna tiburo，该物种被认为具有雌性留居性）妊娠所用夏季栖息地的样本，开展了核编码单核苷酸多态性（single nucleotide polymorphisms, SNPs）与线粒体控制区序列的空间变异模式评估。线粒体DNA单倍型与推定中性SNPs的地理分布格局证实，墨西哥湾东北海岸存在雌性留居现象与雄性介导的基因流。本研究共鉴定出30个SNP异常位点；其中超过半数位点的等位基因呈现出与纬度相关的选择特征。我们的结果表明，在具有性别偏向性扩散的物种中，栖地留居性可促进局域适应性变异的分选，而……