Phenotypic Heterogeneity in Bacterial Populations

Genetically uniform bacterial cells exhibit heterogeneity such as intrapopulation differences in metabolism as well as variation in growth rate. Additionally, phenotypic heterogeneity in more complex developmental processes where a portion of a population performs specialized functions has been described. Heterogeneity within populations of bacterial cells ensures that a small fraction of the population is prepared to survive adverse environmental conditions. Phenotypic heterogeneity is mediated by two mechanisms: (i) genotypic alterations such as, mutations and rearrangements of specific DNA fragments or (ii) epigenetic phenomenon. Here examples of genotypic as well as epigenetically regulated phenotypic heterogeneity from several bacterial species are presented.