A clinal polymorphism in the insulin signaling transcription factor foxo contributes to life-history adaptation in Drosophila*
A clinal polymorphism in the insulin signaling transcription factor foxo contributes to life-history adaptation in Drosophila*
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DOI：
10.1111/evo.13759
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发表时间：
2019-09-01
期刊：
影响因子：
3.3
通讯作者：
Flatt, Thomas
中科院分区：
文献类型：
--
作者：
Durmaz, Esra;Rajpurohit, Subhash;Flatt, Thomas
适应基因组学的一个基本目标是确定支持适应性状变异的多态性。在黑腹果蝇中，纬度生活史渐变存在于多个大陆上，为解剖适应性遗传学提供了一个极好的系统。我们以前已经确定了许多临床单核苷酸多态性的胰岛素/胰岛素样生长因子信号（IIS），从突变体研究已知的影响生活史的途径。然而，对该途径中天然变体的影响仍然知之甚少。在这里，我们调查两个clinal替代等位基因在foxo，IIS的转录效应，影响健身组件（活力，大小，耐饥饿，脂肪含量）。我们评估了这种多态性从北美的无性系重组远交种群，固定为低或高纬度的等位基因，从近交DGRP线。由于饮食和温度调节IIS，我们在两种温度（18摄氏度，25摄氏度）和两种糖源和含量不同的饮食中对等位基因进行了表型分析。与倾斜的预期一致，高纬度等位基因赋予更大的身体尺寸和减少翼负荷。等位基因在饥饿抗性和FOXO的转录靶点胰岛素样受体的表达方面也存在差异。等位基因反应规范大多是平行的，很少GxE相互作用。总之，我们的研究结果表明，IIS的变化作出了重大贡献，临床生活史适应。
A fundamental aim of adaptation genomics is to identify polymorphisms that underpin variation in fitness traits. In Drosophila melanogaster, latitudinal life-history clines exist on multiple continents and make an excellent system for dissecting the genetics of adaptation. We have previously identified numerous clinal single-nucleotide polymorphism in insulin/insulin-like growth factor signaling (IIS), a pathway known from mutant studies to affect life history. However, the effects of natural variants in this pathway remain poorly understood. Here we investigate how two clinal alternative alleles at foxo, a transcriptional effector of IIS, affect fitness components (viability, size, starvation resistance, fat content). We assessed this polymorphism from the North American cline by reconstituting outbred populations, fixed for either the low- or high-latitude allele, from inbred DGRP lines. Because diet and temperature modulate IIS, we phenotyped alleles across two temperatures (18 degrees C, 25 degrees C) and two diets differing in sugar source and content. Consistent with clinal expectations, the high-latitude allele conferred larger body size and reduced wing loading. Alleles also differed in starvation resistance and expression of insulin-like receptor, a transcriptional target of FOXO. Allelic reaction norms were mostly parallel, with few GxE interactions. Together, our results suggest that variation in IIS makes a major contribution to clinal life-history adaptation.