Selective sweeps in a 2-locus model for sex-ratio meiotic drive in Drosophila simulans
Selective sweeps in a 2-locus model for sex-ratio meiotic drive in Drosophila simulans
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DOI：
10.1093/molbev/msm269
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发表时间：
2008-02-01
影响因子：
10.7
通讯作者：
Montchamp-Moreau, Catherine
中科院分区：
文献类型：
--
作者：
Derome, Nicolas;Baudry, Emmanuelle;Montchamp-Moreau, Catherine
识别受正选择的基因座的一种方法是检测给定染色体区域中选择性扫描的特征。它揭示了DNA多态性模式从结合理论预测的中性平衡的偏离。我们调查的DNA序列变异的区域以前确定为造成“性别比”的减数分裂驱动果蝇simulans。我们发现的证据表明，这一系统进化的积极选择在2个相邻的基因座，因此似乎需要同时减数分裂驱动发生。这两个区域相距约150 kb，相当于0.1 cM的遗传距离。在这两个基因座上携带减数分裂驱动等位基因的染色体可能具有很大的传递优势，但这并没有消除每个基因座上选择的个体特征。该染色体片段结合了2个关键区域之间的高水平连锁不平衡和高重组率。其结果是，选择扫描的2个特征性状-变异的减少和单倍型测试中选择中性的偏离-表现出双峰模式。连锁不平衡水平表明，在本研究中使用的马达加斯加自然群体中，选择性扫描可能是最近的100年。
A way to identify loci subject to positive selection is to detect the signature of selective sweeps in given chromosomal regions. It is revealed by the departure of DNA polymorphism patterns from the neutral equilibrium predicted by coalescent theory. We surveyed DNA sequence variation in a region formerly identified as causing "sex-ratio" meiotic drive in Drosophila simulans. We found evidence that this system evolved by positive selection at 2 neighboring loci, which thus appear to be required simultaneously for meiotic drive to occur. The 2 regions are approximately 150-kb distant, corresponding to a genetic distance of 0.1 cM. The presumably large transmission advantage of chromosomes carrying meiotic drive alleles at both loci has not erased the individual signature of selection at each locus. This chromosome fragment combines a high level of linkage disequilibrium between the 2 critical regions with a high recombination rate. As a result, 2 characteristic traits of selective sweeps-the reduction of variation and the departure from selective neutrality in haplotype tests-show a bimodal pattern. Linkage disequilibrium level indicates that, in the natural population from Madagascar used in this study, the selective sweep may be as recent as 100 years.