Am Nat. 2020 Nov;196(5):577-596. doi: 10.1086/710956. Epub 2020 Sep 28.
AbstractSome species show high rates of reproductive failure, which is puzzling because natural selection works against such failure in every generation. Hatching failure is common in both captive and wild zebra finches (), yet little is known about its proximate causes. Here we analyze data on reproductive performance (the fate of >23,000 eggs) based on up to 14 years of breeding of four captive zebra finch populations. We find that virtually all aspects of reproductive performance are negatively affected by inbreeding (mean ); by an early-starting, age-related decline (mean ); and by poor early-life nutrition (mean ). However, these effects together explain only about 3% of the variance in infertility, offspring mortality, fecundity, and fitness. In contrast, individual repeatability of different fitness components varied between 15% and 50%. As expected, we found relatively low heritability in fitness components (median: 7% of phenotypic variation and 29% of individually repeatable variation). Yet some of the heritable variation in fitness appears to be maintained by antagonistic pleiotropy (negative genetic correlations) between male fitness traits and female and offspring fitness traits. The large amount of unexplained variation suggests a potentially important role of local dominance and epistasis, including the possibility of segregating genetic incompatibilities.
摘要
有些物种表现出高比例的繁殖失败，这令人费解，因为自然选择在每一代都反对这种失败。孵化失败在圈养和野生斑马雀（）中都很常见，但对其近因知之甚少。在这里，我们分析了基于对四个圈养斑马雀种群长达 14 年的繁殖数据（超过 23000 个卵的命运）。我们发现，繁殖性能的几乎所有方面都受到近交（平均）、与年龄相关的早期衰退（平均）和早期生活营养差（平均）的负面影响。然而，这些影响总共仅解释了不孕、后代死亡率、繁殖力和适应性方差的约 3%。相比之下，不同适应度成分的个体可重复性在 15%至 50%之间变化。不出所料，我们在适应度成分中发现了相对较低的遗传力（中位数：表型变异的 7%和个体可重复变异的 29%）。然而，适应度的一些可遗传变异似乎是由雄性适应度特征与雌性和后代适应度特征之间的拮抗多效性（负遗传相关）维持的。大量无法解释的变异表明局部显性和上位性（包括遗传不相容性分离的可能性）可能发挥了重要作用。
