A simple genetic basis of adaptation to a novel thermal environment results in complex metabolic rewiring in Drosophila

Background: Population genetic theory predicts that rapid adaptation is largely driven by complex traits encoded by many loci of small effect. Because large-effect loci are quickly fixed in natural populations, they should not contribute much to rapid adaptation. Results: To investigate the genetic architecture of thermal adaptation — a highly complex trait — we performed experimental evolution on a natural Drosophila simulans population. Transcriptome and respiration measurements reveal extensive metabolic rewiring after only approximately 60 generations in a hot environment. Analysis of genome-wide polymorphisms identifies two interacting selection targets, Sestrin and SNF4Aγ, pointing to AMPK, a central metabolic switch, as a key factor for thermal adaptation. Conclusions: Our results demonstrate that large-effect loci segregating at intermediate allele frequencies can allow natural populations to rapidly respond to selection. Because SNF4Aγ also exhibits clinal variation in va...Background: 群体遗传学理论预测，快速适应性演化主要由受众多小效应位点编码的复杂性状所驱动。由于大效应位点在自然种群中会快速被固定，因此它们对快速适应性演化的贡献应当十分有限。 Results: 为探究热适应性演化——一类高度复杂的性状——的遗传结构，我们对自然种群的拟果蝇（Drosophila simulans）开展了实验演化研究。转录组与呼吸代谢测定结果显示，仅在高温环境中继代约60代后，该种群便出现了广泛的代谢重编程。全基因组多态性分析鉴定出两个存在互作的选择靶标：Sestrin与SNF4Aγ，这指向作为核心代谢开关的腺苷酸活化蛋白激酶（AMP-activated protein kinase，AMPK）是热适应性演化的关键因子。 Conclusions: 本研究结果表明，以中等等位基因频率分离留存的大效应位点，可使自然种群快速响应选择压力。由于SNF4Aγ在[...]中亦存在渐变变异。