The complete mitochondrial genome of the relict frog Leiopelma archeyi: Insights into the root of the frog Tree of Life
The complete mitochondrial genome of the relict frog Leiopelma archeyi: Insights into the root of the frog Tree of Life
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DOI：
10.3109/19401736.2010.513973
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发表时间：
2010-10-01
影响因子：
--
通讯作者：
Zardoya, Rafael
中科院分区：
文献类型：
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作者：
Irisarri, Iker;San Mauro, Diego;Zardoya, Rafael
在蛙类系统学中，确定无尾两栖动物生命树的根仍然是一个有争议的和悬而未决的问题。传统上认为，在现存的蛙中，有两个属的分布是最基本的：新西兰特有的Leiopelma和生活在北美的Ascaphus。然而，它们特定的系统发育地位是相当难以捉摸的，因为每个属都表现出许多自形，并且它们一起保留了许多共形特征。因此，对于Leiopelma和Ascaphus的相对系统发育位置，已经提出了几种不同的假说。为了区分这些相互竞争的系统发育假说，我们对Leiopelma archeyi的完整线粒体(Mt)基因组进行了测序，并将其与之前报道的青蛙mt基因组(包括Ascaphus truei)一起用于推断主要无尾两栖动物谱系的强大系统发育。重建的最大似然法和贝叶斯推断的系统发育恢复了相同的拓扑结构，支持Acaphus和Leiopelma的姐妹群关系，并将该支系置于无尾两栖动物树的底部。有趣的是，青蛙mt基因组显示出一种新的基因排列，影响细胞色素b、trnt、NADH脱氢酶亚单位6、trnE和trnP基因的相对位置。基因顺序改变的串联复制-随机丢失模型解释了这种新的青蛙mt基因组排列的起源，这与在一些鱼类和火蜥蜴中报道的其他序列是一致的。这些结果与其他脊椎动物mt基因组的比较数据一起，提供了控制区5‘端是基因顺序重排的热点的证据。
Determining the root of the anuran Tree of Life is still a contentious and open question in frog systematics. Two genera with disjunct distributions have been traditionally considered the most basal among extant frogs: Leiopelma, which is endemic to New Zealand, and Ascaphus, which lives in North America. However, their specific phylogenetic position is rather elusive because each genus shows many autapomorphies, and together they retain many symplesiomorphic characters. Therefore, several alternative hypotheses have been proposed regarding the relative phylogenetic position of both Leiopelma and Ascaphus. In order to distinguish among these competing phylogenetic hypotheses, we sequenced the complete mitochondrial (mt) genome of Leiopelma archeyi and used it along with previously reported frog mt genomes (including that of Ascaphus truei) to infer a robust phylogeny of major anuran lineages. The reconstructed maximum likelihood and Bayesian inference phylogenies recovered identical topology, which supports the sister group relationship of Ascaphus and Leiopelma, and the placement of this clade at the base of the anuran tree. Interestingly, the mt genome of L. archeyi displays a novel gene arrangement in frog mt genomes affecting the relative position of cytochrome b, trnT, NADH dehydrogenase subunit 6, trnE, and trnP genes. The tandem duplication-random loss model of gene order change explains the origin of this novel frog mt genome arrangement, which is convergent with others reported in some fishes and salamanders. These results, together with comparative data for other available vertebrate mt genomes, provide evidence that the 5' end of the control region is a hot spot for gene order rearrangement.