Genes are expressed in response to a signal, and no two bacteria in a population are ever receiving exactly the same signal, hence heterogeneity of gene express

Genes are expressed in response to a signal, and no two bacteria in a population are ever receiving exactly the same signal, hence heterogeneity of gene expression. Some bacteria have a "persistent" phenotype which means that they slow their metabolism way down, stop replicating and just hang out although they are genetically identical to the rest of the population. Normally (or in nutrient-rich conditions) this puts them at a disadvantage vs. the rest of the population, but in the event that there is an antibiotic compound the persisters survive way better. Persisters make up a very small percentage of the total population but can end up re-seeding the entire population after antibiotic treatment. It's not clear how the persister phenotype is regulated, so scientists often refer to it as stochastic. The really interesting thing is that persisters and non-persisters are genetically identical, and it's thought that maintaining some level of persisters in population is a bet-hedging strategy of the population. *will edit with sources in a little bit