Heterozygosity and orange colouration are strongly associated in the guppy (Poecilia reticulata)

The good-genes-as-heterozygosity hypothesis predicts that more elaborate male sexual ornaments are associated with higher levels of heterozygosity. Recent theoretical work suggests that such associations are likely to arise in finite, structured populations. We investigated the correlation between multilocus heterozygosity (MLH), which was estimated using 13 microsatellite loci, and male coloration in a wild population of guppies (Poecilia reticulata), a model species in sexual selection research. We found that MLH was a significant predictor of the relative area of orange spots, a trait that is subject to strong female preference in this species. Neither the relative area of black spots nor the number of black or orange spots was significantly correlated with MLH. We found no statistical support for local effects (i.e. strong effects of heterozygosity at specific markers), which suggests that relative orange spots area reflects genome-wide heterozygosity.

优质基因作为杂合性假说（good-genes-as-heterozygosity hypothesis）预测，雄性更为精致的性征装饰物与更高水平的杂合性存在关联。近期的理论研究表明，此类关联极有可能在有限的结构化种群中产生。本研究以性选择研究的模式物种——野生孔雀鱼（Poecilia reticulata）种群为研究对象，探究了基于13个微卫星位点（microsatellite loci）估算得到的多位点杂合性（multilocus heterozygosity, MLH）与雄性体色之间的相关性。研究发现，多位点杂合性是橙色斑块相对面积的显著预测因子，而该性状在本物种中受到雌性强烈的择偶偏好。黑色斑块的相对面积，以及黑色或橙色斑块的数量，均与多位点杂合性无显著相关性。本研究未发现支持局部效应（即特定标记位点上杂合性的强效应）的统计学证据，这表明橙色斑块的相对面积反映了全基因组水平的杂合性。