A mitochondrial DNA phylogeny of African clawed frogs: phylogeography and implications for polyploid evolution
A mitochondrial DNA phylogeny of African clawed frogs: phylogeography and implications for polyploid evolution
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DOI：
10.1016/j.ympev.2004.04.018
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发表时间：
2004-10-01
影响因子：
4.1
通讯作者：
Cannatella, DC
中科院分区：
文献类型：
--
作者：
Evans, BJ;Kelley, DB;Cannatella, DC
非洲爪蛙（Silurana和Xenopus）是科学研究的模式生物，其异源多倍化发生在多个场合，产生四倍体，四倍体和十二倍体物种。为了更好地了解它们的进化，在这里我们估计了所有描述和一些未描述物种的线粒体DNA同源性。我们研究的时间和多样化的位置，并测试假设的频率多倍体物种形成和分类。使用一个宽松的分子钟，我们估计，现存的爪蛙谱系起源于冈瓦纳大陆解体后，约6370万年前，95%的置信区间从50.4到8130万年前。志留纪和爪蟾的两个主要谱系在撒哈拉以南非洲有重叠的分布，和分散-vicariance分析表明，爪蛙起源于中部和/或东部赤道非洲。大多数或所有现存物种起源于更新世之前;最近的雨林避难所可能是保存现有物种的“救生艇”，而不是许多新的成功谱系起源的“物种泵”。我们估计，多倍化发生在爪蛙至少六次。(C)2004年爱思唯尔公司All rights reserved.
The African clawed frogs (Silurana and Xenopus), model organisms for scientific inquiry, are unusual in that allopolyploidization has occurred on multiple occasions, giving rise to tetraploid, octoploid, and dodecaploid species. To better understand their evolution, here we estimate a mitochondrial DNA phylogeny from all described and some undescribed species. We examine the timing and location of diversification, and test hypotheses concerning the frequency of polyploid speciation and taxonomy. Using a relaxed molecular clock, we estimate that extant clawed frog lineages originated well after the breakup of Gondwana, about 63.7 million years ago, with a 95% confidence interval from 50.4 to 81.3 million years ago. Silurana and two major lineages of Xenopus have overlapping distributions in sub-Saharan Africa, and dispersal-vicariance analysis suggests that clawed frogs originated in central and/or eastern equatorial Africa. Most or all extant species originated before the Pleistocene; recent rainforest refugia probably acted as "lifeboats" that preserved existing species, rather than "species pumps" where many new successful lineages originated. We estimate that polyploidization occurred at least six times in clawed frogs. (C) 2004 Elsevier Inc. All rights reserved.