Theoretical and Experimental Studies of the Population and Evolutionary Dynamics of Bacteria and Bacteriophage.

NARRATIVE Although the viruses of bacteria and archaea (phage) are touted to be the most abundant organisms on Earth and research with bacteriophage has played and continues to play a central role in the development of molecular biology and biotechnology, there remain fundamental unanswered questions about the evolution of these viruses and their contribution to the ecology and evolution of their hosts. The proposed jointly theoretical and experimental study of the population biology and evolution of bacteriophage will address and answer three classes of questions: 1- Existence conditions; under what conditions will phage be maintained and regulate the densities of these host populations? 2- Horizontal versus vertical transmission: under what conditions will natural selection favor the evolution and maintenance of a lysogenic rather than a purely lytic mode of phage replication? 3- The evolution and maintenance of adaptive immunity: under what conditions will selection mediated by virulent and temperate phage lead to the evolution of and maintenance of CRISPR-Cas - mediated adaptive immunity? !