Data from: Joint allelic effects on fitness and metric traits

Theoretical explanations of empirically observed standing genetic variation, mutation, and selection suggest that many alleles must jointly affect fitness and metric traits. However, there are few direct demonstrations of the nature and extent of these pleiotropic associations. We implemented a mutation accumulation (MA) divergence experimental design in Drosophila serrata to segregate genetic variants for fitness and metric traits. By exploiting naturally occurring MA line extinctions as a measure of line-level total fitness, manipulating sexual selection, and measuring productivity we were able to demonstrate genetic covariance between fitness and standard metric traits, wing size and shape. Larger size was associated with lower total fitness and male sexual fitness, but higher productivity. Multivariate wing shape traits, capturing major axes of wing shape variation among MA lines, evolved only in the absence of sexual selection, and to the greatest extent in lines that went extinct, indicating that mutations contributing wing shape variation also typically had deleterious effects on both total fitness and male sexual fitness. This pleiotropic covariance of metric traits with fitness will drive their evolution, and generate the appearance of selection on the metric traits even in the absence of a direct contribution to fitness.针对实验观测到的现存遗传变异（standing genetic variation）、突变与选择的理论解释表明，诸多等位基因（alleles）需同时影响适合度（fitness）与度量性状（metric traits）。然而，目前针对这类多效性（pleiotropic）关联的本质与范围的直接验证仍十分有限。本研究在锯果蝇（Drosophila serrata）中采用了突变积累（mutation accumulation, MA）分化实验设计，以分离出影响适合度与度量性状的遗传变异。通过将自然发生的MA品系灭绝事件作为品系层面总适合度的评估指标，同时操控性选择（sexual selection）并测定繁殖力（productivity），我们成功证实了适合度与标准度量性状——翅大小与翅形之间的遗传协方差（genetic covariance）。个体体型越大，总适合度与雄性性适合度越低，但繁殖力越高。能够反映MA品系间翅形变异主要维度的多变量翅形性状，仅在无性选择条件下发生演化，且在灭绝品系中演化程度最高，这表明引发翅形变异的突变通常同时对总适合度与雄性性适合度产生有害影响。这类度量性状与适合度之间的多效性协方差将推动其演化，且即便这些度量性状未直接对适合度产生贡献，也会使这些性状呈现出受选择作用的表观特征。