Abstracts (first author)
The evolution and genetics of susceptibility to infectious disease
It is common to find considerable genetic variation in susceptibility to infection in natural populations. Not only is this variation abundant, but it can have important implications for health, economic output and the coevolution between hosts and parasites. Within populations of Drosophila, we have found that selection by viruses tends in increase genetic variation in disease susceptibility, due to directional selection increasing the frequency of recently arisen major-effect alleles that increase resistance. Furthermore, bacterial symbionts can also protect many species of Drosophila against viral infection, and the spread of these symbionts also has the potential to generate rapid shifts in the susceptibility of flies to viruses. Overall, susceptibility to viral infection is controlled by a small number of major-effect genes and symbionts that are under strong selection and rapidly change in frequency.