Data from: Genes and group membership predict gidgee skink (Egernia stokesii) reproductive pairs

Due to their role in mate choice, disease resistance and kin recognition, genes of the major histocompatibility complex (MHC) are good candidates for investigating genetic-based mate choice. MHC based mate choice is context dependent and influenced by many factors including social structure. Social structure diversity makes the Egernia group of lizards suitable for comparative studies of MHC based mate choice. We investigated mate choice in the gidgee skink (Egernia stokesii), a lizard that exhibits high levels of social group and spatial stability. Group membership was incorporated into tests of the good genes as heterozygosity and compatible genes hypotheses for adaptive (MHC) and neutral (microsatellite) genetic diversity (n = 47 individuals genotyped). Females were more likely to pair with a male with higher MHC diversity and with whom they had a lower degree of microsatellite relatedness. Males were more likely to pair with a female with higher microsatellite heterozygosity and with whom they shared a lower proportion of MHC alleles. Lizards were more likely to mate with an individual from within, rather than outside, their social group, which confirmed earlier findings for this species and indicated mate choice had already largely occurred prior to either social group formation or acceptance of an individual into an existing group. Thus, a combination of genes and group membership, rather than group membership alone, predicted mate choice in this species. This work will contribute to an enhanced understanding of squamate group formation and a deeper understanding of the evolution of sociality within all vertebrates.

主要组织相容性复合体（major histocompatibility complex, MHC）基因因其在配偶选择、疾病抗性以及亲缘识别中发挥的关键作用，成为探究基于遗传机制的配偶选择行为的理想候选研究靶点。基于MHC的配偶选择具有情境依赖性，且受社会结构等诸多因素的共同影响。社会结构的多样性特征使得石龙子属（Egernia）蜥蜴类群成为开展MHC依赖型配偶选择比较研究的优质模型。本研究以吉奇石龙子（Egernia stokesii）为研究对象，该物种展现出高度稳定的社会群体结构与空间分布特征。研究将群体归属变量纳入针对适应性（MHC）与中性（微卫星，microsatellite）遗传多样性的"优质基因杂合性假说"与"相容基因假说"的配偶选择测试中，本次研究共完成47个个体的基因分型。结果显示，雌性个体更倾向于与MHC多样性更高、且微卫星亲缘度更低的雄性配对；雄性个体则更倾向于与微卫星杂合度更高、且共享MHC等位基因比例更低的雌性配对。此外，蜥蜴个体更倾向与社会群体内部而非外部的个体交配，该结果验证了该物种此前的相关研究发现，同时表明配偶选择行为在社会群体形成或接纳新个体加入现有群体之前就已大体完成。综上，本物种的配偶选择由遗传因素与群体归属共同决定，而非仅由群体归属单一决定。本研究有助于深化对有鳞目爬行动物群体形成机制的理解，并推动对所有脊椎动物社会性演化的认知。