Microbial bet-hedging: the power of being different.

Bet-hedging is an evolutionary theory that describes how risk spreading can increase fitness of a genotype in an unpredictably changing environment. To achieve risk spreading, maladapted phenotypes develop within isogenic populations that may be fit for a future environment. In recent years, various observations of microbial phenotypic heterogeneity have been denoted as bet-hedging strategies, sometimes without sufficient evidence to support this claim. Here, we discuss selected examples of microbial phenotypic heterogeneity that so far do seem consistent with the evolutionary theory concept of bet-hedging.