A paper published last week in PLoS Computational Biology uses predictive modeling to study recombination patterns in HIV. Scientists looked at a set of recombinant HIV genomes to construct a model for where recombination between the two viral RNA strands occurs. They found that the exchange took place more at either side of the env gene, suggesting that despite the wide variety of mutant forms, "only a minority of recombination events appear to be of significance to the evolution of HIV-1."