Do we Owe HIV Resistance to Smallpox?
(Alison Galvani, Yale University)

The high frequency, recent origin and geographic distribution of the CR5-∆32 deletion allele together indicate that it has been intensely selected in Europe. While the allele confers resistance against HIV-1, HIV has not existed in the human population for long enough to account for this
selective pressure. The prevailing hypothesis is that the selective rise of CR5-∆32 to its current frequency can be attributed to bubonic plague. By employing a population genetic framework that takes into account the temporal pattern and age-dependent nature of specific diseases, we find that smallpox is more consistent with this historical role.