Božičević Vedran, Hutter Stephan, Stephan Wolfgang, Wollstein Andreas
Section of Evolutionary Biology, Department of Biology II, University of Munich, D-82152, Planegg-Martinsried, Germany.
Mol Ecol. 2016 Mar;25(5):1175-91. doi: 10.1111/mec.13464. Epub 2016 Jan 18.
We studied Drosophila melanogaster populations from Europe (the Netherlands and France) and Africa (Rwanda and Zambia) to uncover genetic evidence of adaptation to cold. We present here four lines of evidence for genes involved in cold adaptation from four perspectives: (i) the frequency of SNPs at genes previously known to be associated with chill-coma recovery time (CCRT), startle reflex (SR) and resistance to starvation stress (RSS) vary along environmental gradients and therefore among populations; (ii) SNPs of genes that correlate significantly with latitude and altitude in African and European populations overlap with SNPs that correlate with a latitudinal cline from North America; (iii) at the genomewide level, the top candidate genes are enriched in gene ontology (GO) terms that are related to cold tolerance; (iv) GO enriched terms from North American clinal genes overlap significantly with those from Africa and Europe. Each SNP was tested in 10 independent runs of Bayenv2, using the median Bayes factors to ascertain candidate genes. None of the candidate genes were found close to the breakpoints of cosmopolitan inversions, and only four candidate genes were linked to QTLs related to CCRT. To overcome the limitation that we used only four populations to test correlations with environmental gradients, we performed simulations to estimate the power of our approach for detecting selection. Based on our results, we propose a novel network of genes that is involved in cold adaptation.
我们研究了来自欧洲（荷兰和法国）和非洲（卢旺达和赞比亚）的黑腹果蝇种群，以揭示适应寒冷的遗传证据。我们从四个角度展示了与冷适应相关基因的四条证据线：（i）先前已知与冷昏迷恢复时间（CCRT）、惊吓反射（SR）和抗饥饿应激（RSS）相关的基因处单核苷酸多态性（SNP）的频率沿环境梯度变化，因此在不同种群间也存在差异；（ii）非洲和欧洲种群中与纬度和海拔显著相关的基因的SNP，与来自北美的与纬度渐变相关的SNP重叠；（iii）在全基因组水平上，顶级候选基因在与耐寒性相关的基因本体（GO）术语中富集；（iv）来自北美渐变基因的GO富集术语与来自非洲和欧洲的那些术语显著重叠。每个SNP在Bayenv2的10次独立运行中进行测试，使用中位数贝叶斯因子来确定候选基因。未发现任何候选基因靠近世界性倒位的断点，并且只有四个候选基因与与CCRT相关的数量性状位点（QTL）连锁。为了克服我们仅使用四个种群来测试与环境梯度相关性的局限性，我们进行了模拟以估计我们检测选择的方法的效能。基于我们的结果，我们提出了一个涉及冷适应的新基因网络。
