Genetic relatedness in animal societies is often a factor that drives the structure of social groups. In the marine world, most studies which have investigated this question have focused on marine mammals such as whales and dolphins. For sharks, recent studies have demonstrated preferential associations among individuals from which social communities emerge. Assortment patterns have been found according to phenotypic or behavioural traits but the role of genetic relatedness in shaping the social structure of adult shark populations has, to the best our knowledge, never been investigated. Here, we used a social network analysis crossed with DNA microsatellite genotyping to investigate the role of the genetic relatedness in the social structure of a blacktip reef shark (Carcharhinus melanopterus) population. Based on data from 156 groups of sharks, we used generalized affiliation indices to isolate social preferences from non-social associations, controlling for the contribution of sex, size, gregariousness, spatial and temporal overlap on social associations, to test for the influence of genetic relatedness on social structure. A double permutation procedure was employed to confirm our results and account for issues arising from potentially elevated type I and type II error rates. Kinship was not a predictor of associations and affiliations among sharks at the dyad or community levels as individuals tended to associate independently of the genetic relatedness among them. The lack of parental care in this species may contribute to the breakdown of family links in the population early in life, thereby preventing the formation of kin-based social networks.

中文翻译：

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亲属关系不能预测鲨鱼社交网络的结构

动物社会中的遗传相关性通常是驱动社会群体结构的因素。在海洋世界中，大多数研究此问题的研究都集中在鲸鱼和海豚等海洋哺乳动物上。对于鲨鱼，最近的研究表明，社会社区所产生的个体之间存在优先联系。已经根据表型或行为特征找到了分类模式，但是就我们所知，遗传相关性在塑造成年鲨鱼种群社会结构中的作用尚未得到研究。在这里，我们使用了社交网络分析与DNA微卫星基因分型相结合，以研究遗传相关性在黑鳍礁鲨（Carcharhinus melanopterus）种群的社会结构中的作用。根据156组鲨鱼的数据，我们使用广义隶属度指数将社会偏好与非社会联想隔离开来，控制性别，规模，社交，时空重叠对社会联想的贡献，以检验遗传相关性对社会结构的影响。采用双重置换程序来确认我们的结果并解决由可能提高的I型和II型错误率引起的问题。亲缘关系并不能预测鲨鱼在二元组或社区水平上的关联和隶属关系，因为个体倾向于独立于它们之间的遗传相关性进行关联。该物种缺乏父母的照顾可能会导致生命早期人口中的家庭联系破裂，从而阻止基于亲属的社交网络的形成。