Evaluating genomic divergence and parallelism in replicate ecomorphs from young and old cichlid adaptive radiations
Evaluating genomic divergence and parallelism in replicate ecomorphs from young and old cichlid adaptive radiations
复制标题
评估年轻和年老丽鱼适应性辐射复制生态形态中的基因组分歧和平行性
DOI：
10.1111/mec.13463
复制
发表时间：
2016
影响因子：
4.9
通讯作者：
O. Seehausen
中科院分区：
文献类型：
--
作者：
M. McGee;R. Neches;O. Seehausen
对近亲物种的比较基因组研究通常集中在某一特定分化阶段的单个物种对上。这使得我们很难推断物种形成期间和之后的进化过程的连续性。在此，我们使用全基因组重测序来研究三种功能和生态分化非常相似但年龄不同的同域慈鲷物种的基因组分化模式。我们发现在线粒体基因组和核基因组中，随着时间的推移，基因组差异越来越大。与许多其他系统相比，我们发现在这些慈鲷中，相对分化升高的区域也表现出绝对分化的增加。我们在所有三个物种对比较的异常区域中发现了趋同进化的特征，但其程度是适度的，并且在任何一对中强烈分化的区域往往只在其他对中略微升高，这与可重复但多基因基础的特征相一致。我们的研究结果表明，在所有三个物种对中所看到的强烈的功能性表型分化通常与基因组分化的明确特征相关，即使在最年轻的物种对中也是如此。
Comparative genomic studies of closely related species typically focus on single species pairs at one given stage of divergence. That makes it difficult to infer the continuum of evolutionary process during speciation and beyond. Here, we use whole‐genome resequencing to examine genomic patterns of divergence in three sympatric cichlid species pairs with very similar functional and ecological differentiation, but different ages. We find a strong signature of increasing genomic divergence with time in both the mitochondrial genome and the nuclear genome. In contrast to many other systems, we find that in these cichlids, regions of elevated relative differentiation also exhibit increased absolute differentiation. We detect a signature of convergent evolution in a comparison of outlier regions across all three species pair comparisons, but the extent of it is modest, and regions that are strongly divergent in any one pair tend to be only slightly elevated in the other pairs, consistent with a repeatable but polygenic basis of traits that characterize the ecomorphs. Our results suggest that strong functional phenotypic differentiation, as seen in all three species pairs, is generally associated with a clear signature of genomic divergence, even in the youngest species pair.