MBE Advance Access published online on October 14, 2008
Molecular Biology and Evolution, doi:10.1093/molbev/msn234
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Research Article |
Hantavirus Evolution in Relation to its Rodent and Insectivore Hosts: No Evidence for Co-divergence
1 Center for Infectious Disease Dynamics, Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
2 Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
3 School of Information Technologies, Sydney Bioinformatics, and Centre for Mathematical Biology; University of Sydney, NSW2006, Australia
Corresponding Author: Cadhla Ramsden, Mailing Address: Department of Biology, Mueller Laboratory, The Pennsylvania State University, University Park, PA 16802, USA, Telephone: 814-863-6471, Fax: 814-863-6471, Email: cbr134{at}psu.edu
Received for publication August 20, 2008. Revision received October 1, 2008. Accepted for publication October 9, 2008.
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 co-speciated 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 co-divergence in two ways: (i) we used co-phylogenetic reconciliation analysis to assess the fit of the virus tree onto that of the host, and (ii) we estimated the evolutionary rates and divergence times for the Hantavirus genus using a Bayesian MCMC method, and similarly compared these to with those of their hosts. Our reconciliation analysis provided no evidence for a history of co-divergence between hantaviruses and their hosts. Further, the divergence times for the Hantavirus genus were many orders of magnitude too recent to correspond with the time-scale 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.
Key Words: hantavirus • co-divergence • evolution • co-phylogeny • host-switching