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 β -defensins, 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 β -defensin (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 the presence of eggshell bacteria in their clutches and hatching success. We found weak associations between the presence of AvBD genes, BKA and eggshell bacteria. Our results suggested that homozygosity at some loci may be advantageous for defence against bacteria. Variability at β -defensin 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 β -defensin genes are significantly affecting fitness-related traits in wild populations.

阐明个体间表型变异的遗传基础，是理解进化过程的关键一环。针对β-防御素（β-defensins）这类先天免疫基因的近期研究表明，该类基因存在高水平多态性。然而，目前研究者尚未量化这类基因变异对野生种群免疫反应及适合度相关性状的影响。本研究以成年树燕（Tachycineta bicolor）为研究对象，探究了6个禽β-防御素（avian β-defensin，AvBD）基因的变异与免疫功能、繁殖成功率之间的关联。研究通过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）衡量免疫功能，以雏鸟出飞成功率作为繁殖成功的指标，分析了遗传变异、免疫功能与繁殖成功三者间的关联。此外，本研究还探究了雌鸟免疫相关遗传学特征与其窝卵卵壳细菌定植情况及孵化成功率之间的关联。结果发现，AvBD基因变异、细菌杀伤能力与卵壳细菌定植三者间仅存在微弱关联。研究结果显示，部分基因座的纯合性或许有助于机体抵御细菌感染。β-防御素基因的变异与孵化成功率、出飞成功率均无显著关联。双亲的细菌杀伤能力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。