Centre of Evolutionary Biology, School of Animal Biology, The University of Western Australia, Crawley WA 6009, Australia.
Evolution. 2010 Jul;64(7):1935-43. doi: 10.1111/j.1558-5646.2010.00975.x. Epub 2010 Feb 15.
Latitudinal clines in quantitative traits are common, but surprisingly little is known about the genetic bases of these divergences and how they vary within and between clines. Here, we use line-cross analysis to investigate the genetic architecture of wing size divergences at varying spatial scales along a body size cline in Drosophila melanogaster. Our results revealed that divergences in wing size along the cline were due to strong additive effects. Significant nonadditive genetic effects, including epistasis and maternal effects, were also detected, but they were relatively minor in comparison to the additive effects and none were common to all crosses. There was no evidence of increased epistasis in crosses between more geographically distant populations and, unlike in previous studies, we found no significant dominance effects on wing size in any cross. Our results suggest there is little variation in the genetic control of wing size along the length of the Australian cline. They also highlight marked inconsistencies in the magnitude of dominance effects across studies, which may reflect different opportunities for mutation accumulation while lines are in laboratory culture.
纬度上数量性状的渐变是常见的，但令人惊讶的是，我们对于这些差异的遗传基础以及它们在渐变内和渐变间的变化方式知之甚少。在这里，我们使用线交叉分析来研究黑腹果蝇体型渐变过程中不同空间尺度上翅膀大小差异的遗传结构。我们的结果表明，渐变过程中翅膀大小的差异是由于强烈的加性效应所致。还检测到了显著的非加性遗传效应，包括上位性和母性效应，但与加性效应相比，它们相对较小，而且没有一个在所有杂交中都普遍存在。在地理上距离较远的种群之间的杂交中没有证据表明上位性增加，而且与之前的研究不同，我们在任何杂交中都没有发现翅膀大小的显著显性效应。我们的研究结果表明，在澳大利亚渐变过程中，翅膀大小的遗传控制变化很小。它们还突出了跨研究中显性效应幅度的显著不一致性，这可能反映了在实验室培养过程中，不同的突变积累机会。
