Ramsden Cadhla, Holmes Edward C, Charleston Michael A
Center for Infectious Disease Dynamics, Department of Biology, Mueller Laboratory, The Pennsylvania State University, USA.
Mol Biol Evol. 2009 Jan;26(1):143-53. doi: 10.1093/molbev/msn234. Epub 2008 Oct 14.
Hantaviruses are considered one of the best examples of a long-term association between RNA viruses and their hosts. Based on the appearance of strong host specificity, it has been suggested that hantaviruses cospeciated with the rodents and insectivores they infect since these mammals last shared a common ancestor, approximately 100 million years ago. We tested this hypothesis of host-virus codivergence in two ways: 1) we used cophylogenetic reconciliation analysis to assess the fit of the virus tree onto that of the host and 2) we estimated the evolutionary rates and divergence times for the Hantavirus genus using a Bayesian Markov Chain Monte Carlo method and similarly compared these with those of their hosts. Our reconciliation analysis provided no evidence for a history of codivergence between hantaviruses and their hosts. Further, the divergence times for the Hantavirus genus were many orders of magnitude too recent to correspond with the timescale of their hosts' speciation. We therefore propose that apparent similarities between the phylogenies of hantaviruses and their mammalian hosts are the result of a more recent history of preferential host switching and local adaptation. Based on the presence of clade-defining amino acids in all genomic segments, we propose that the patterns of amino acid replacement in these viruses are also compatible with a history of host-specific adaptation.
汉坦病毒被认为是RNA病毒与其宿主长期关联的最佳例子之一。基于强烈的宿主特异性的表现，有人提出汉坦病毒与其感染的啮齿动物和食虫动物自这些哺乳动物最后拥有共同祖先（约1亿年前）以来共同进化。我们通过两种方式检验了宿主-病毒共同进化的这一假设：1）我们使用共系统发育和解分析来评估病毒树与宿主树的拟合度；2）我们使用贝叶斯马尔可夫链蒙特卡罗方法估计汉坦病毒属的进化速率和分歧时间，并同样将这些与它们宿主的进行比较。我们的和解分析没有提供汉坦病毒与其宿主之间存在共同进化历史的证据。此外，汉坦病毒属的分歧时间比其宿主物种形成的时间尺度要近许多个数量级。因此，我们提出汉坦病毒与其哺乳动物宿主系统发育之间明显的相似性是更近的优先宿主转换和局部适应历史的结果。基于所有基因组片段中分支定义氨基酸的存在，我们提出这些病毒中氨基酸替换的模式也与宿主特异性适应的历史相符。
