Genetic basis of continuous variation in the levels and modular inheritance of pigmentation in cichlid fishes

Variation in pigmentation type and levels is a hallmark of myriad evolutionary radiations, and biologists have long been fascinated by the factors that promote and maintain variation in coloration across populations. Here we provide insights into the genetic basis of complex and continuous patterns of color variation in cichlid fishes, which offer a vast diversity of pigmentation patterns that have evolved in response to both natural and sexual selection. Specifically, we crossed two divergent cichlid species to generate an F2 mapping population that exhibited extensive variation in pigmentation levels and patterns. Our experimental design is robust in that it combines traditional quantitative trait locus (QTL) analysis with population genomics, which has allowed us to move efficiently from QTL interval to candidate gene. In total, we detected 41 QTL and 13 epistatic interactions that underlie melanocyte- and xanthophore-based coloration across the fins and flanks of these fishes. We al...

色素沉着类型与水平的变异是众多进化辐射事件的标志性特征，长期以来，生物学家一直对推动并维持种群间体色变异的因素抱有浓厚兴趣。本研究针对慈鲷鱼类复杂且连续的体色变异模式的遗传基础展开解析——这类鱼类拥有极为丰富的色素沉着表型多样性，其演化是自然选择与性选择共同作用的结果。具体而言，我们通过两个分化程度显著的慈鲷物种杂交构建了F2定位群体，该群体展现出色素沉着水平与模式的广泛变异。本实验设计兼具严谨性：它将传统数量性状位点（quantitative trait locus, QTL）分析与群体基因组学相结合，使我们能够高效地从QTL区间定位到候选基因。最终，我们共检测到41个数量性状位点以及13个上位性互作位点，这些位点共同构成了慈鲷鳍部与体侧基于黑色素细胞和黄色素细胞的着色性状的遗传基础。