Data from: Linking innate immunogenetic variation with phenotypic traits in a wild population of tree swallows, Tachycineta bicolor

Unravelling the genetic basis of phenotypic variation among individuals is an important step in our understanding of evolution. Recent studies of innate immune genes, such as β­defensins, revealed that these genes had high levels of polymorphism. However, researchers have yet to quantify the effects of such variability on immune responses and fitness-related traits in wild populations. In this study, we assessed how the variability at six avian β­defensin (AvBD) genes was linked to an immune function and reproductive success in adult tree swallows (Tachycineta bicolor). We investigated the links between genetic variations using single nucleotide polymorphisms at AvBD genes, immune function as the bacterial killing ability (BKA) and fledging success. We assessed how female immunogenetics were linked to eggshell bacteria presence in their clutches and hatching success. We found weak associations between AvBD genes, BKA and eggshell bacteria presence. Our results suggested that homozygosity at some loci may be advantageous for defence against bacteria. Variability at β­defensin genes was not related to either hatching or fledging success. BKA of parents was positively linked with fledging success. More studies are needed to assess whether or not β­defensin genes are significantly impacting fitness-related traits in wild populations.

阐明个体间表型变异的遗传基础，是我们理解演化进程的关键一环。近年来针对先天免疫基因（如β防御素（β-defensins））的研究显示，这类基因具有极高的多态性水平。然而，研究者尚未量化这类基因变异对野生种群免疫应答及适合度相关性状的影响。本研究以成年双色树燕（Tachycineta bicolor）为研究对象，探究了6个禽β防御素（AvBD）基因的变异与免疫功能及繁殖成功率的关联。本研究以AvBD基因的单核苷酸多态性表征遗传变异、以细菌杀伤能力（BKA）表征免疫功能，分析了上述指标与雏鸟出飞成功率之间的关联；同时分析了雌性个体的免疫遗传特征与其窝卵蛋壳细菌定植情况及孵化成功率的关联。本研究发现AvBD基因、BKA与蛋壳细菌定植情况之间仅存在微弱关联。研究结果显示，部分位点的纯合性或许有助于提升细菌防御能力。β防御素基因的变异与孵化成功率及雏鸟出飞成功率均无显著关联。亲本的BKA水平与雏鸟出飞成功率呈正相关。未来仍需开展更多研究，以明确β防御素基因是否会对野生种群的适合度相关性状产生显著影响。