Data from: Beyond mean allelic effects: a locus at the major color gene MC1R associates also with differing levels of phenotypic and genetic (co)variance for coloration in barn owls

The mean phenotypic effects of a discovered variant help to predict major aspects of the evolution and inheritance of a phenotype. However, differences in the phenotypic variance associated to distinct genotypes are often overlooked despite being suggestive of processes that largely influence phenotypic evolution, such as interactions between the genotypes with the environment or the genetic background. We present empirical evidence for a mutation at the melanocortin-1-receptor gene, a major vertebrate coloration gene, affecting phenotypic variance in the barn owl, Tyto alba. The white MC1R allele, which associates with whiter plumage coloration, also associates with a pronounced phenotypic and additive genetic variance for distinct color traits. Contrarily, the rufous allele, associated with a rufous coloration, relates to a lower phenotypic and additive genetic variance, suggesting that this allele may be epistatic over other color loci. Variance differences between genotypes entailed differences in the strength of phenotypic and genetic associations between color traits, suggesting that differences in variance also alter the level of integration between traits. This study highlights that addressing variance differences of genotypes in wild populations provides interesting new insights into the evolutionary mechanisms and the genetic architecture underlying the phenotype.

已发现的变异体的平均表型效应，有助于预测表型演化与遗传的核心特征。然而，与不同基因型相关的表型方差差异往往被忽视，尽管这些差异暗示了诸多对表型演化具有重要影响的过程，例如基因型与环境或遗传背景间的互作。本研究针对黑皮质素1受体基因（melanocortin-1-receptor gene，脊椎动物关键色素沉着基因）上的一处突变，提供了其影响仓鸮（Tyto alba）表型方差的实验证据。与更洁白羽毛色泽相关的白色MC1R等位基因，同时也与多项色泽性状的显著表型方差及加性遗传方差相关联。反之，与赤褐色羽毛色泽相关的赤褐色等位基因，则对应更低的表型方差与加性遗传方差，这提示该等位基因可能对其他色素位点存在上位性效应。不同基因型间的方差差异，导致了色泽性状间表型与遗传关联强度的差异，这表明方差差异同样会改变性状间的整合水平。本研究强调，针对野生种群中基因型的方差差异展开分析，能够为解析表型背后的演化机制与遗传架构提供新颖且富有价值的见解。