BREAKING COUPLING SYMMETRY. “Bacillus subtilis represents an example (rather than an exception) of the intercellular communication that may operate (maybe in a more stochastic manner) in most single-celled organisms, and may allow the breaking of symmetry required for the coupling of programmed cell death to survival at the level of the colony. The view presented here implies that it is also one of the crucial mechanisms that has allowed the emergence of an evolutionarily stable form of programmed cell death.”
http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html