Data from: The molecular genetics of clinal variation: a case study of ebony and thoracic trident pigmentation in Drosophila melanogaster from eastern Australia

Widespread pigmentation diversity coupled with a well-defined genetic system of melanin synthesis and patterning in Drosophila provides an excellent opportunity to study phenotypes undergoing evolutionary change. Pigmentation variation is highly correlated with different ecological variables and is thought to reflect adaptations to different environments. Several studies have linked candidate genes from D. melanogaster to intra-population variation and interspecific morphological divergence, but less clearly to variation among populations forming pigmentation clines. We characterised a new thoracic trident pigmentation cline in D. melanogaster populations from eastern Australia, and applied a candidate gene approach to explain the majority of the geographically structured phenotypic variation. More melanised populations from higher latitudes tended to express less ebony than their tropical counterparts, and an independent artificial selection experiment confirmed this association. By partitioning temperature dependent effects, we showed that the genetic differences underlying clinal patterns for trident variation at 25°C do not explain the patterns observed at 16°C. Changes in thoracic trident pigmentation could be a common evolutionary response to climatically-mediated environmental pressures. On the Australian east coast most of the changes appear to be associated with regulatory divergence of the ebony gene but this depends on temperature.果蝇属（Drosophila）中广泛存在的色素沉着多样性，加上其黑色素合成与模式形成的明确遗传系统，为研究经历演化改变的表型提供了绝佳的研究契机。色素沉着变异与多种生态变量高度相关，被认为反映了物种对不同环境的适应性演化。已有多项研究将黑腹果蝇（D. melanogaster）的候选基因与种群内变异及种间形态分化建立关联，但针对形成色素沉着渐变群（cline）的种群间变异，相关关联尚不够明确。本研究对澳大利亚东部的黑腹果蝇种群中一种全新的胸部三叉状色素沉着渐变群进行了表征，并采用候选基因法解释了绝大多数具有地理结构的表型变异。纬度更高的种群黑色素沉着程度更强，其黑檀体基因（ebony）的表达量往往低于热带种群；一项独立的人工选择实验验证了这一关联。通过拆分温度依赖效应，我们发现，25℃下三叉状色素变异渐变群背后的遗传差异，无法解释16℃下观测到的相关模式。胸部三叉状色素沉着的改变，可能是物种响应气候介导的环境压力的一种常见演化策略。在澳大利亚东海岸，绝大多数色素变异似乎与黑檀体基因的调控分化相关，但这一关联依赖于温度条件。