Bacteria in colonies don’t reproduce sexually and are genetically identical, yet they can prepare in advance for changing environmental conditions.



Yale University researchers have shown that bacteria carry out this sophisticated strategy by producing cells with differing amounts of specific proteins that govern their response to chemical signals.

In a computer simulation, shown in the accompanying animation, a population of E. coli bacteria begins to track signals emitted from a nearby colonization site. Although the bacteria are genetically identical, they have different amounts of proteins. These differences, indicated by different colors in the animation, result in different behaviors. Cells in blue explore the environment quickly but not in large numbers, while cells in orange arrive later at their target en masse.

This variability allows bacteria to harbor cells that act as generalists or specialists for different environments. “Bacteria need a mix of cells to survive, like an investor needs a mix of stocks and bonds for the best return,” said Nicholas Frankel, a graduate student in the Department of Molecular, Cellular, and Developmental Biology, and lead author of the research published online in the journal eLife.