Analysis of recombination and natural selection in human enterovirus 71.

The development of effective vaccines and antiviral prophylaxis against human enterovirus 71 (EV71) has been hampered by the extensive antigenic diversity of the virus. To gain new insights into the evolutionary processes that create this genetic diversity, the TreeOrder Scan Method and RDP program were employed to detect recombination events in the genome, and then parsimony-based and maximum-likelihood-based methods were used to detect natural selection effects on viral proteins. Recombination analysis provided strong evidence for recombination events in the majority of the sequences analyzed. Recombination events were found to be distributed nonrandomly with the highest frequency at the 3D region. Furthermore, positive selection was only detected at site 145 of VP1 by the maximum likelihood-based method. These results reveal that EV71 proteins are extensively influenced by stabilizing selection. We conclude that recombination may play a more important role than positive selection in the formation of genetic diversity.