Evolution of Modern Birds Revealed by Mitogenomics: Timing the Radiation and Origin of Major Orders
Evolution of Modern Birds Revealed by Mitogenomics: Timing the Radiation and Origin of Major Orders
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DOI：
10.1093/molbev/msr014
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发表时间：
2011-06-01
影响因子：
10.7
通讯作者：
Escalante, Ananias A.
中科院分区：
文献类型：
--
作者：
Pacheco, M. Andreina;Battistuzzi, Fabia U.;Escalante, Ananias A.
线粒体基因和基因组是鸟类进化研究的主要数据来源之一。这使得鸟类的有丝分裂基因组学研究成为鸟类进化生物学激烈争论的核心。事实上，完整的mt基因组被积极地用于揭示主要目之间的系统发育关系，而单个基因（例如，细胞色素c氧化酶I [COX 1]）被认为是物种鉴定和定义物种边界（DNA条形码）的标准。在这项调查中，我们研究的起源时间和进化关系之间的Neoaves订单使用完整的mt基因组。首先，我们能够通过分析80个mt基因组，包括本次调查中报告的17个新序列，解决先前在Neoaves进化的深节点观察到的多分裂现象。作为一个例子，我们发现的证据表明，columbiforms和charadriforms是姐妹群。总的来说，我们的分析表明，通过改进分类学采样，完整的mt基因组可以解决主要鸟类群体之间的进化关系。其次，我们用我们的系统发育假说来估计主要鸟类的起源时间，以此来测试它们的多样化是否发生在白垩纪/第三纪（K/T）边界之前。这些时间树是使用几种分子测年方法和保守的校准点估计的。虽然我们发现的时间估计比其他人报道的略年轻，但大多数主要订单起源于K/T边界之前。最后，我们使用我们的时间树来估计每个mt基因的进化速率。我们发现mt基因的突变率在不同的鸟类群体中有很大的差异。COX 1是Neoaves目中变异较小的基因，也是各谱系中变异率最低的基因。这些发现支持选择mt基因中的考克斯1作为开发鸟类DNA条形码方法的靶点。
Mitochondrial (mt) genes and genomes are among the major sources of data for evolutionary studies in birds. This places mitogenomic studies in birds at the core of intense debates in avian evolutionary biology. Indeed, complete mt genomes are actively been used to unveil the phylogenetic relationships among major orders, whereas single genes (e.g., cytochrome c oxidase I [COX1]) are considered standard for species identification and defining species boundaries (DNA barcoding). In this investigation, we study the time of origin and evolutionary relationships among Neoaves orders using complete mt genomes. First, we were able to solve polytomies previously observed at the deep nodes of the Neoaves phylogeny by analyzing 80 mt genomes, including 17 new sequences reported in this investigation. As an example, we found evidence indicating that columbiforms and charadriforms are sister groups. Overall, our analyses indicate that by improving the taxonomic sampling, complete mt genomes can solve the evolutionary relationships among major bird groups. Second, we used our phylogenetic hypotheses to estimate the time of origin of major avian orders as a way to test if their diversification took place prior to the Cretaceous/Tertiary (K/T) boundary. Such timetrees were estimated using several molecular dating approaches and conservative calibration points. Whereas we found time estimates slightly younger than those reported by others, most of the major orders originated prior to the K/T boundary. Finally, we used our timetrees to estimate the rate of evolution of each mt gene. We found great variation on the mutation rates among mt genes and within different bird groups. COX1 was the gene with less variation among Neoaves orders and the one with the least amount of rate heterogeneity across lineages. Such findings support the choice of COX 1 among mt genes as target for developing DNA barcoding approaches in birds.