Data from: Pigmentation and fitness trade-offs through the lens of artificial selection

Pigmentation is a classic phenotype that varies widely and adaptively in nature both within and among taxa. Genes underlying pigmentation phenotype are highly pleiotropic, creating the potential for functional trade-offs. However, the basic tenets of this trade-off hypothesis with respect to life-history traits have not been directly addressed. In natural populations of Drosophila melanogaster, the degree of melanin pigmentation covaries with fecundity and several other fitness traits. To examine correlations and potential trade-offs associated with variation in pigmentation, we selected replicate outbred populations for extreme pigmentation phenotypes. Replicate populations responded rapidly to the selection regime and after 100 generations of artificial selection were phenotyped for pigmentation as well as the two basic fitness parameters of fecundity and longevity. Our data demonstrate that selection on pigmentation resulted in a significant shift in both fecundity and longevity profiles. Selection for dark pigmentation resulted in greater fecundity and no pronounced change in longevity, whereas selection for light pigmentation decreased longevity but did not affect fecundity. Our results indicate the pleiotropic nature of alleles underlying pigmentation phenotype and elucidate possible trade-offs between pigmentation and fitness traits that may shape patterns of phenotypic variation in natural populations.

色素沉着（pigmentation）是一类经典表型，在自然界中类群内及类群间广泛存在且具有适应性变异。调控色素沉着表型的相关基因具有高度多效性（pleiotropic），从而存在产生功能性权衡的潜在可能。然而，该权衡假说针对生活史性状的核心原则尚未得到直接验证。在黑腹果蝇（Drosophila melanogaster）的自然种群中，黑色素沉着程度与繁殖力（fecundity）及其他多项适合度性状（fitness traits）存在共变异关系。为探究色素沉着变异相关的相关性与潜在权衡关系，我们针对极端色素沉着表型筛选了重复远交种群。重复种群对该选择方案响应迅速，在经过100代人工选择（artificial selection）后，我们对其进行了色素沉着表型鉴定，并测定了繁殖力与寿命（longevity）这两项核心适合度参数。本研究数据显示，针对色素沉着的选择使繁殖力与寿命的分布模式均发生了显著改变。针对深色素沉着的选择提升了繁殖力，且未对寿命产生显著影响；而针对浅色素沉着的选择则缩短了寿命，但未改变繁殖力。本研究结果证实了色素沉着表型相关等位基因（alleles）的多效性本质，并阐明了色素沉着与适合度性状之间可能存在的权衡关系，这类权衡或可塑造自然种群的表型变异模式。