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.

果蝇中广泛存在的色素沉着多样性，加之其调控黑色素合成与模式形成的成熟遗传系统，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，被认为是物种对不同环境产生适应性演化的直观体现。已有多项研究将黑腹果蝇（Drosophila melanogaster）的候选基因与种群内变异、种间形态分化建立了关联，但对于形成色素渐变群的种群间变异的解释则相对模糊。我们对澳大利亚东部黑腹果蝇种群中一种全新的胸部三叉形色素渐变群进行了系统表征，并通过候选基因策略解析了大部分具有地理结构的表型变异。纬度更高的黑化种群相较于热带种群，其黑檀体基因（ebony）的表达量更低；独立开展的人工选择实验也验证了这一关联。通过拆分温度依赖的调控效应，我们发现25℃下调控三叉形色素变异的渐变群遗传差异，无法解释16℃下观测到的表型模式。胸部三叉形色素沉着的改变，可能是物种应对气候介导的环境压力的一种普遍演化响应。在澳大利亚东海岸，多数色素变异似乎与黑檀体基因（ebony）的调控分化相关，但这一关联受温度调控。