Genomic evidence for divergence with gene flow in host races of the larch budmoth
Genomic evidence for divergence with gene flow in host races of the larch budmoth
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DOI：
10.1098/rspb.2003.2574
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发表时间：
2004-01-07
影响因子：
4.7
通讯作者：
Mallet, J
中科院分区：
文献类型：
--
作者：
Emelianov, I;Marec, F;Mallet, J
面对基因流动的生态分化最近被认为是物种形成和适应性辐射的潜在重要原因。在这里，我们开发了一种基因组方法来测试落叶松budmoth Zeiraphera diniana（鳞翅目：飞蛾科）的同域寄主种族的差异选择。我们分析了同域和异域居群中92个个体的数百个扩增片段长度多态性标记，并在两个回交育群中用于将标记定位到单个染色体。结果直接证实了自然杂交的存在，表明不同寄主种间的分子分化在染色体间具有较强的异质性（平均分化水平F-ST = 0.216）。然而，当我们分析同一宿主种族在地理上分离的种群之间的差异时，没有发现基因组异质性。我们得出结论，染色体间同域分化水平的差异是少数连锁群上的分化选择的足迹，加上在其余连锁群上可观的基因流动使种族间变异均质化。这些结果，再加上最近对姐妹物种对的多位点分析，表明在存在基因流动的情况下，选择驱动的遗传分化同域阶段可能是物种形成的一个特征。
Ecological divergence in the face of gene flow has recently become implicated as a potentially important cause of speciation and adaptive radiation. Here, we develop a genomic approach to test for divergent selection in sympatric host races of the larch budmoth Zeiraphera diniana (Lepidoptera: Tortricidae). We analysed hundreds of amplified fragment length polymorphism markers in 92 individuals in sympatric and allopatric populations, and in two backcross broods used to map the markers to individual chromosomes. The results directly confirm the existence of natural hybridization and demonstrate strong heterogeneity between chromosomes in terms of molecular divergence between host races (the average level of divergence was F-ST = 0.216). However, genomic heterogeneity was not found when we analysed divergence between geographically separated populations of the same host race. We conclude that the variance of the level of sympatric divergence among chromosomes is the footprint of divergent selection acting on a few linkage groups, combined with appreciable gene flow that homogenizes between-race variation at the remaining linkage groups. These results, coupled with other recent multilocus analyses of sister species pairs, demonstrate that selection-driven sympatric phase of genetic divergence in the presence of gene flow is a likely feature of speciation.