Data from: Mother-offspring and nest mate resemblance but no heritability in early-life telomere length in white-throated dippers

Telomeres are protective DNA–protein complexes located at the ends of eukaryotic chromosomes, whose length has been shown to predict life-history parameters in various species. Although this suggests that telomere length is subject to natural selection, its evolutionary dynamics crucially depends on its heritability. Using pedigree data for a population of white-throated dippers (Cinclus cinclus), we test whether and how variation in early-life relative telomere length (RTL, measured as the number of telomeric repeats relative to a control gene using qPCR) is transmitted across generations. We disentangle the relative effects of genes and environment and test for sex-specific patterns of inheritance. There was strong and significant resemblance among offspring sharing the same nest and offspring of the same cohort. Furthermore, although offspring resemble their mother, and there is some indication for an effect of inbreeding, additive genetic variance and heritability are close to zero. We find no evidence for a role of either maternal imprinting or Z-linked inheritance in generating these patterns, suggesting they are due to non-genetic maternal and common environment effects instead. We conclude that in this wild bird population, environmental factors are the main drivers of variation in early-life RTL, which will severely bias estimates of heritability when not modelled explicitly.

端粒（telomeres）是定位于真核染色体末端的保护性DNA-蛋白质复合物，其长度已被证实可预测多个物种的生活史参数。尽管这提示端粒长度受自然选择作用，但其进化动态关键取决于其遗传力。本研究以白喉河乌（Cinclus cinclus）野生种群的谱系数据为基础，检验生命早期相对端粒长度（RTL，即通过qPCR（实时定量聚合酶链反应）测定的端粒重复序列数与对照基因的比值）的变异是否可跨代传递、具体传递机制；同时解析基因与环境的相对效应，并检验遗传模式的性别特异性。研究结果显示，同巢后代与同批后代之间存在显著且强烈的表型相似性。此外，尽管后代与其母亲存在表型相似性，且存在一定的近交效应迹象，但加性遗传方差与遗传力均趋近于零。本研究未发现母体印记或Z连锁遗传参与塑造上述模式的证据，提示这些相似性实则由非遗传的母体效应与共同环境效应所致。综上，在该野生鸟类种群中，环境因素是生命早期相对端粒长度变异的主要驱动因素；若未对环境因素进行明确建模，将严重偏倚遗传力的估算结果。