M. xanthus fruiting bodiesFRANCESCA FIEGNAKin discrimination, in which an organism favors genetically related individuals over non-related individuals in social behaviors, can emerge among related bacterial strains that evolved from a common ancestor and were cultured under different laboratory conditions, according to a study on the social bacterium Myxococcus xanthus published today (July 6) in PNAS.
“Often when we see these kinds of social incompatibilities, or greater cooperation between close relatives than between strangers, it’s interpreted in the context of kin selection theory, which posits that cooperation—at least within species—will evolve when there’s preferential interactions that occur between relatives that share genes for cooperation,” said Gregory Velicer of ETH Zürich, who led the work. “[We have found that] reduced cooperation between different types can arise not because of any selection for incompatibility, per se, but rather simply because you had these different complex social systems evolving independently of one another.”
Under certain conditions, genetically identical colonies of M. xanthus swabbed on opposite ends of an agar plate grow toward one another, merging to form a single colony. But as Velicer and ...
