In conclusion, by experimentally reproducing the generation of HIV-1 recombinants, we demonstrate that the distinctive distribution of breakpoints found in natural viruses is strongly shaped by both the mechanism of recombination, and the relative functionality of the recombinant genes. Thus, HIV evolution might not be the relentlessly unpredictable process it sometimes seems, and exploiting this evidence to pre-empt and counter the most favoured evolutionary tactics of this virus may ultimately be an efficient means by which we can devise effective vaccines and improve drugs against the virus.