Distinct genetic architectures underlie divergent thorax, leg, and wing pigmentation between Drosophila elegans and D. gunungcola

Understanding the genetic basis of species differences is a major goal in evolutionary biology. Pigmentation divergence between Drosophila species often involves genetic changes in pigmentation candidate genes that pattern the body and wings, but it remains unclear how these changes affect pigmentation evolution in multiple body parts between the same diverging species. Drosophila elegans and D. gunungcola show pigmentation differences in the thorax, legs, and wings, with D. elegans exhibiting male-specific wing spots and D. gunungcola lacking wing spots with intensely dark thoraces and legs. Here, we performed QTL mapping to identify the genetic architecture of these differences. We find a large effect QTL on the X chromosome for all three body parts. QTL on Muller Element E were found for thorax pigmentation in both backcrosses but were only marginally significant in one backcross for the legs and wings. Consistent with this observation, we isolated the effects of the Muller Element E...解析物种间差异的遗传基础，是进化生物学的核心研究目标之一。果蝇属物种间的色素沉着分化，往往涉及调控躯体与翅膀形态建成的色素沉着候选基因的遗传变异，但目前仍不清楚此类变异如何在同一分化物种间的多个躯体部位影响色素沉着的演化过程。优雅果蝇（Drosophila elegans）与D. gunungcola在胸部、腿部与翅膀上存在显著色素沉着差异：优雅果蝇具有雄性特异性翅膀斑点，而D. gunungcola无翅膀斑点，且胸部与腿部颜色深黑。本研究通过数量性状位点（QTL）定位，解析此类表型差异的遗传结构。我们发现，X染色体上存在对三个躯体部位均具有显著效应的QTL。在两个回交群体中，穆勒元件E（Muller Element E）上的QTL均与胸部色素沉着显著相关，但仅在一个回交群体中，其对腿部与翅膀色素沉着的效应仅表现出边际显著性。与该观测结果一致，我们成功分离得到了穆勒元件E的遗传效应……