Centre for Environmental Stress and Adaptation Research, School of Biological Sciences, Monash University, Vic. 3800 Australia.
Mol Ecol. 2010 Feb;19(4):775-84. doi: 10.1111/j.1365-294X.2009.04509.x. Epub 2010 Jan 14.
Body size often shows adaptive clines in many ectotherms across altitude and latitude, but little is known about the genetic basis of these adaptive clines. Here we identify a polymorphism in the Dca (Drosophila cold acclimation) gene in Drosophila melanogaster that influences wing size, affects wing:thorax allometry and also controls a substantial proportion of the clinal wing-size variation. A polymorphism in the promoter region of Dca had two common alleles showing strong reciprocal clinal variation in frequency with latitude along the east coast of Australia. The Dca-237 allele increased towards the tropics where wing size is smaller. A within-population association study highlighted that an increase in the frequency of this allele decreased wing size but did not influence thorax size. A manipulated increase in the level of expression of Dca achieved through UAS-GAL4 was associated with a decrease in wing size but had no effect on thorax size. This was consistent with higher Dca expression levels in family lines with higher frequency of the Dca-237 allele. Genetic variation in the promoter region of the Dca gene appears to influence adaptive size variation in the eastern Australian cline of Drosophila melanogaster and accounts for more than 10% of the genetic variation in size within and between populations.
在许多变温动物中，体型通常表现出对海拔和纬度的适应性梯度，但对于这些适应性梯度的遗传基础知之甚少。在这里，我们在黑腹果蝇(Drosophila melanogaster)的 Dca(果蝇冷驯化)基因中发现了一个多态性，该多态性影响翅膀大小，影响翅膀与胸部的比例，并且控制着相当一部分的翅膀大小的渐变变异。Dca 启动子区域的一个多态性具有两个常见的等位基因，它们在沿着澳大利亚东海岸的纬度上表现出强烈的相互渐变频率。Dca-237 等位基因在热带地区增加，那里的翅膀尺寸较小。种群内的关联研究强调，这种等位基因频率的增加会降低翅膀的大小，但不会影响胸部的大小。通过 UAS-GAL4 实现的 Dca 水平的人为增加表达与翅膀大小的减少有关，但对胸部大小没有影响。这与具有更高频率的 Dca-237 等位基因的家系中 Dca 表达水平较高的情况一致。Dca 基因启动子区域的遗传变异似乎影响了澳大利亚东部黑腹果蝇渐变群中适应性大小的变化，并且在种群内和种群间的大小的遗传变异中占 10%以上。
