Isolation by adaptation in Neochlamisus leaf beetles: host-related selection promotes neutral genomic divergence
Isolation by adaptation in Neochlamisus leaf beetles: host-related selection promotes neutral genomic divergence
复制标题
DOI：
10.1111/j.1365-294x.2011.05311.x
复制
发表时间：
2011-11-01
影响因子：
4.9
通讯作者：
Nosil, Patrik
中科院分区：
文献类型：
--
作者：
Funk, Daniel J.;Egan, Scott P.;Nosil, Patrik
这项研究测试了不同的自然选择如何在生态物种形成过程中促进基因组分化。具体地说，我们使用适应性生态差异(这里是寄主植物使用和偏好的种群差异)作为选择强度的替代指标，并通过成对的种群比较来评估适应性和遗传分化水平之间的相关性。正相关将揭示我们的假说所预测的模式，即“适应隔离”(IBA)。值得注意的是，IBA不仅适用于选定的基因座，也适用于中性基因座。这可能反映了差异选择对中性基因座的影响，这些中性基因座与差异选择的基因座有松散的联系，或者对基因流限制的影响促进了所有基因座的遗传漂移，包括与在差异选择下进化的中性基因座完全不连锁的中性基因座。在这里，我们评估了与枫树和柳树相关的新叶甲虫种群中的IBA。为此，我们收集了寄主偏好数据来构建适应性分化指数，并使用AFLP(扩增片段长度多态)和线粒体序列来量化遗传分化。部分Mantel检验表明，IBA在假定中性和假定选择的(‘离群值’)AFLP基因座的‘集合’分析中具有显著意义。在单独评估单个中性基因座遗传分化的“特定基因座”分析中，也有12%的人恢复了这种模式。这些结果为选择对中性基因组分化的广泛影响提供了证据。我们的集体发现表明，寄主相关的选择可能在草食性昆虫中性和选择基因区域的种群基因组分化中发挥重要作用。
This study tests how divergent natural selection promotes genomic differentiation during ecological speciation. Specifically, we use adaptive ecological divergence (here, population divergence in host plant use and preference) as a proxy for selection strength and evaluate the correlation between levels of adaptive and genetic differentiation across pairwise population comparisons. Positive correlations would reveal the pattern predicted by our hypothesis, that of 'isolation by adaptation' (IBA). Notably, IBA is predicted not only for selected loci but also for neutral loci. This may reflect the effects of divergent selection on neutral loci that are 'loosely linked' to divergently selected loci or on geneflow restriction that facilitates genetic drift at all loci, including neutral loci that are completely unlinked to those evolving under divergent selection. Here, we evaluate IBA in maple-and willow-associated populations of Neochlamisus bebbianae leaf beetles. To do so, we collected host preference data to construct adaptive divergence indices and used AFLPs (amplified fragment length polymorphisms) and mitochondrial sequences to quantify genetic differentiation. Partial Mantel tests showed significant IBA in 'pooled' analyses of putatively neutral and of putatively selected ('outlier') AFLP loci. This pattern was also recovered in 12% of 'locus-specific' analyses that separately evaluated genetic differentiation at individual neutral loci. These results provided evidence for widespread effects of selection on neutral genomic divergence. Our collective findings indicate that host-related selection may play important roles in the population genomic differentiation of both neutral and selected gene regions in herbivorous insects.