For bacteria, assassination can breed cooperation

Microbe’s use of toxic weaponry creates single-strain clumps

WASHINGTON — Bacteria assassinating each other when crowded together ironically can favor the evolution of cooperation.

When a Vibrio cholerae bacterium jostles neighbors in crowds on crab shells, it fires a spring-loaded toxin injection. Siblings with the same immunity genes don’t die, but genetically different strains of V.