9421237 Lensky Microorganisms perform various ecological functions that may be either beneficial (e.g., decomposition of wastes) or deleterious (e.g., pathogens of humans and crops), depending on the particular species and environmental context. Much is known about the biochemistry and molecular genetics of certain microorganisms, but very little is known about the population dynamics of microorganisms and how various ecological and genetic factors affect microbial evolution. The proposed research seeks to identify and quantify important ecological and genetic processes that may influence the dynamics of microbial populations. There are two major objectives (1) To model mathematically the dynamics of host-pathogen interactions in order to understand the ecological and evolutionary forces that shape virulence, especially in relation to specific modes of pathogen transmission and (2) To quantify experimentally the genetic variation in bacterial populations for such important phenotypic traits as competitiveness and cell size, including the contribution of deleterious mutations, substitution of favorable mutations, and balanced polymorphisms to this variation.
