A highly pleiotropic amino acid polymorphism in the Drosophila insulin receptor contributes to life-history adaptation.
A highly pleiotropic amino acid polymorphism in the Drosophila insulin receptor contributes to life-history adaptation.
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DOI：
10.1111/evo.12546
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发表时间：
2014-12
期刊：
影响因子：
--
通讯作者：
Schmidt PS
中科院分区：
文献类型：
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作者：
Paaby AB;Bergland AO;Behrman EL;Schmidt PS
寻找支持适应性变异的特定核苷酸是进化生物学的主要目标，但多基因性状是一个挑战，因为复杂的基因型-表型关系可能会掩盖个体等位基因的影响。然而，在大量野生种群中进行的自然选择可以改变等位基因频率，并指示基因组的功能区域。此前，我们发现果蝇胰岛素受体中复杂氨基酸插入-缺失多态的两个最常见的等位基因在北美和澳大利亚大陆的频率上显示出独立的、平行的倾斜。在这里，我们报告说，临床是稳定的，至少五年期间，多态也表现出时间上的等位基因频率的变化，同时季节性变化。我们测试了等位基因对胰岛素信号水平、繁殖力、发育时间、体型、压力耐受性和寿命的影响。我们发现，等位基因与这些特征的可预测差异有关，这与果蝇生活史在不同地理位置的变化模式一致，这可能反映了对异质气候环境的适应。这些结果暗示胰岛素信号是果蝇生活史适应的主要中介，并表明生活史的权衡可以用单个基因的广泛多效性来解释。
Finding the specific nucleotides that underlie adaptive variation is a major goal in evolutionary biology, but polygenic traits pose a challenge because the complex genotype–phenotype relationship can obscure the effects of individual alleles. However, natural selection working in large wild populations can shift allele frequencies and indicate functional regions of the genome. Previously, we showed that the two most common alleles of a complex amino acid insertion–deletion polymorphism in the Drosophila insulin receptor show independent, parallel clines in frequency across the North American and Australian continents. Here, we report that the cline is stable over at least a five-year period and that the polymorphism also demonstrates temporal shifts in allele frequency concurrent with seasonal change. We tested the alleles for effects on levels of insulin signaling, fecundity, development time, body size, stress tolerance, and life span. We find that the alleles are associated with predictable differences in these traits, consistent with patterns of Drosophila life-history variation across geography that likely reflect adaptation to the heterogeneous climatic environment. These results implicate insulin signaling as a major mediator of life-history adaptation in Drosophila, and suggest that life-history trade-offs can be explained by extensive pleiotropy at a single locus.