We have been gathering a large amount of data from these studies, and from these data, we may be able to link recombinants to transmission. The study of these recombinants is already giving us clues about the regions of the HIV genome that may be important to transmission. In Tanzania we have a large number of distinct recombinants. One, a CD recombinant, was shown to be responsible for almost 10 percent of the HIV transmitted from mothers to infants. This recombinant appears to have been generated within this population and to have expanded.
Recombination is responsible for leaps in viral evolution.
Once different HIV subtypes are within human populations, a single person can be exposed to different subtypes, and intersubtype recombination can occur. And since people travel so much, they can be exposed to different viruses. So the virus drives recombination but intersubtype recombination is driven by human behavior. The recombinants we see from Tanzania have such variety, suggesting that many people are being repeatedly exposed to different viruses. So all this may create viruses that are more adapted to spread, that can be more easily transmitted.