Data from: No effect of environmental heterogeneity on the maintenance of genetic variation in wing shape in Drosophila melanogaster

Theory suggests that heterogeneous environments should maintain more genetic variation within populations than homogeneous environments, yet experimental evidence for this effect in quantitative traits has been inconsistent. To examine the effect of heterogeneity on quantitative genetic variation, we maintained replicate populations of Drosophila melanogaster under treatments with constant temperatures, temporally variable temperature, or spatially variable temperature with either panmictic or limited migration. Despite observing differences in fitness and divergence in several wing traits between the environments, we did not find any differences in the additive genetic variance for any wing traits among any of the treatments. Although we found an effect of gene flow constraining adaptive divergence between cages in the limited migration treatment, it did not tend to increase within-population genetic variance relative to any of the other treatments. The lack of any clear and repeatable patterns of response to heterogeneous vs. homogeneous environments across several empirical studies suggests that a single general mechanism for the maintenance of standing genetic variation is unlikely; rather, the relative importance of putative mechanisms likely varies considerably from one trait and ecological context to another.

理论表明，异质环境相较于同质环境更易在种群内维持更多遗传变异，但针对数量性状该效应的实验证据始终存在不一致性。为探究异质性对数量遗传变异的影响，我们在三类处理条件下培养了黑腹果蝇（Drosophila melanogaster）的重复种群：恒温环境、温度随时间波动的环境，以及空间温度异质环境，且每类环境均设置随机交配与有限迁移两种模式。尽管我们观察到不同环境间的适合度存在差异，且多项翅部性状出现了分化，但未发现任何处理组间的翅部性状的加性遗传方差（additive genetic variance）存在显著差异。虽然我们发现，在有限迁移处理组中，基因流会限制笼群间的适应性分化（adaptive divergence），但相较于其他所有处理组，该处理并未显著提升种群内的遗传方差。多项实证研究均未观察到异质环境与同质环境间存在清晰且可重复的响应模式，这说明单一通用机制难以维持现存遗传变异（standing genetic variation）；相反，各类推定机制的相对重要性，很可能因性状与生态背景的不同而存在显著差异。