Microbial Adaptation and Change
The evolution of novel microbes, including antibiotic-resistant strains, depends on diverse members of microbial populations that can thrive in new conditions. Microbes have incredible abilities to change their genetic make-up and evolve faster than their hosts do. Multiple mechanisms ensure the diversity that allows for expansion.
The production of a single, novel gene product may be the key to bacterial survival; however, several gene products working together sometimes provide the advantage. Mutation generates new genes but, unlike higher eukaryotes, bacteria do not undergo sexual reproduction; the typical bacterium simply grows, replicates its DNA, and divides. Therefore, bacterial reproduction does not provide a mechanism for generating progeny with new combinations of genes. How, then, do bacteria obtain new gene assortments, some of which may provide survival?
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