Bacterial ecospecies and ecoclines

All bacteria reproduce clonally but some species exchange DNA frequently enough that they have well mixed geographic gene pools, similar to those found in outbreeding animals and plants. Using data from multiple species we show that these “recombinogenic” bacteria also have genome-wide genetic structures generated by natural selection, including discrete “ecospecies” and continuous “ecoclines”. These structures reflect evolutionary strategies employed within natural populations, which can be dissected using the powerful techniques of molecular microbiology, providing a unique new view into the private lives of bacteria.