Evidence from the evolutionary analysis of nucleotide sequences for a recombinant history of SARS-CoV

The origins and evolutionary history of the Severe Acute Respiratory Syndrome (SARS) coronavirus (SARS-CoV) remain an issue of uncertainty and debate. Based on evolutionary analyses of coronavirus DNA sequences, encompassing an approximately 13 kb stretch of the SARS-TOR2 genome, we provide evidence that SARS-CoV has a recombinant history with lineages of types I and III coronavirus. We identified a minimum of five recombinant regions ranging from 83 to 863 bp in length and including the polymerase, nsp9, nsp10, and nsp14. Our results are consistent with a hypothesis of viral host jumping events, concomitant with the reassortment of bird and mammalian coronaviruses, a scenario analogous to earlier outbreaks of influenzae.