Viral transduction and the dynamics of bacterial adaptation

Abstract

AbstractViral infections can exert a large influence on their hosts’ ecology by causing widespread mortality, but they also shape the evolutionary adaptation of hosts in a number of ways. A major pathway for viruses to do so is through the transfer of genetic material among individual hosts, a process known as transduction. While horizontal gene transfer is known as a major factor in prokaryotic macroevolution, its role in the microevolutionary adaptation of hosts populations is poorly known. By facilitating the transfer of beneficial alleles between host cells, transduction might facilitate and accelerate bacterial adaptation. Conversely, the risk of transferring deleterious alleles may hinder and slow it down. Here we resolve the effect of transduction on bacterial adaptation in a simple ecoevolutionary model for the combined dynamics of transduction and adaptive evolution of an ecological (resource-use) trait. The transfer of beneficial alleles by tranduction speeds up adaptation whereas the transfer of deleterious alleles causes strong stochastic fluctuations of the trait value around the adapted value. In contrast to the expected effect of recombination, which tends to oppose phenotypic diversification, viral transduction can increase host phenotypic diversity.