The ancestors of the simian immunodeficiency viruses (SIVs) that jumped from chimpanzees and monkeys, and ignited the HIV/AIDS pandemic in humans, have been dated to just a few centuries ago. These ages are substantially younger than previous estimates, according to a new study from The University of Arizona in Tucson, published May 1st in the open-access journal PLoS Computational Biology.
SIV has crossed over from chimpanzees and sooty mangabeys to humans at least eleven times, giving rise to several HIV lineages. Although HIV is a virulent pathogen in humans, SIV rarely causes disease in these species or the dozens of other African primate species it naturally infects. That these non-human primates typically remain unaffected after virus exposure has led to the hypothesis that there had been millions of years of coevolution between SIVs and their primate hosts.
The researchers, Joel Wertheim and Dr. Michael Worobey, estimated a rate of virus evolution using viral genetic sequences that had been isolated from infected humans, chimpanzees, and sooty mangabeys between 1975 and 2005. They inferred that the viruses currently circulating in sooty mangabeys and in chimpanzees evolved from ancestors dating to 1809 (1729-1875) and 1492 (1266-1685), respectively. Surprisingly, the independently estimated 'molecular clock' of the monkey viruses was virtually identical to the famously swift rate at which mutations accumulate in HIV genomes.
The authors note that unaccounted-for biases could be masking a deeper age of SIV. They suggest that if these biases do exist, their causes need to be investigated because they might also affect the ability to properly estimate the age of HIV and other viruses.
FINANCIAL DISCLOSURE: This work was supported by the Department of Ecology and Evolutionary Biology at the University of Arizona and the David and Lucile Packard Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
COMPETING INTERESTS: The authors have declared that no competing interests exist.
PLEASE ADD THIS LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.plos.org/10.1371/journal.pcbi.1000377 (link will go live upon embargo lift)
CITATION: Wertheim JO, Worobey M (2009) Dating the Age of the SIV Lineages That Gave Rise to HIV-1 and HIV-2. PLoS Comput Biol 5(5): e1000377. doi:10.1371/journal.pcbi.1000377
email@example.com (preferred method of contact)
Dr. Michael Worobey
This press release refers to an upcoming article in PLoS Computational Biology. The release is provided by the article authors. Any opinions expressed in this release or article are the personal views of the journal staff and/or article contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the releases and articles and your use of such information.
About PLoS Computational Biology
PLoS Computational Biology (www.ploscompbiol.org) features works of exceptional significance that further our understanding of living systems at all scales through the application of computational methods. All works published in PLoS Computational Biology are open access. Everything is immediately available subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org.
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.