Data from: Balanced genetic diversity improves population fitness

Although genetic diversity within a population is suggested to improve population-level fitness and productivity, the existence of these effects is controversial because empirical evidence for an ecological effect of genetic diversity and the underlying mechanisms is scarce and incomplete. Here, we show that the natural single-gene behavioural polymorphism (Rover and sitter) in Drosophila melanogaster has a positive effect on population fitness. Our simple numerical model predicted that the fitness of a polymorphic population would be higher than that expected with two monomorphic populations, but only under balancing selection. Moreover, this positive diversity effect of genetic polymorphism was attributable to complementarity effect, rather than to selection effect. Our empirical tests using the behavioural polymorphism in D. melanogaster clearly supported the model predictions. These results provide direct evidence for an ecological effect of genetic diversity on population fitness and its condition dependence.

尽管学界普遍认为种群内的遗传多样性可提升种群整体的适合度与生产力，但此类效应的存在性仍存在争议——究其原因，遗传多样性的生态效应及其潜在机制的实证证据既稀缺又不完备。本研究以黑腹果蝇（Drosophila melanogaster）天然存在的单基因行为多态型（分为漫游者（Rover）与滞留者（sitter）两种表型）为对象，证实该多态型对种群适合度具有正向影响。我们构建的简易数值模型预测：仅在平衡选择（balancing selection）条件下，多态种群的适合度将高于两个单态种群的预期适合度。此外，遗传多态性所带来的正向多样性效应，源于互补效应（complementarity effect）而非选择效应（selection effect）。我们利用黑腹果蝇的行为多态性开展的实证检验，有力验证了该模型的预测结果。上述研究结果为遗传多样性对种群适合度的生态效应及其条件依赖性提供了直接实证证据。