scientists, Velicer and Yu, deleted certain parts of the M. xanthus genome, making it unable to swarm effectively on soft agar. Individuals were cloned, and allowed to evolve. After a period of 64 weeks, two of the evolving populations had started to swarm outward almost as effectively as normal wild-type colonies. However, the patterns of the swarm were very different from those of the wild-type bacteria. This suggested that they had developed a new way of moving, and Velicer and Yu confirmed this by showing that the new populations had not regained the ability to make pili, which allows wild-type bacteria to swarm. This study addressed questions about the evolution of cooperation between individuals that had plagued scientists for years. Very little is known about the evolutionary mechanisms present in M. xanthus. However, it has been discovered that it can establish a generalist predator relationship with different prey, among which is Escherichia coli. In this predator-prey relationship, a parallel evolution of both species is observed through genomic and phenotypic modifications, producing in subsequent generations a better adaptation of one of the species that is counteracted by the evolution of the other, following a co-evolutionary model known Red Queen hypothesis. However, the evolutionary mechanisms present in M. xanthus that produce this parallel evolution are still unknown. Strains Myxococcus xanthus DK 1622 Myxococcus xanthus DZ2 Myxococcus xanthus DZF1 Myxococcus xanthus NewJersey2 Myxococcus xanthus DSM16526T Whole genome comparisons have indicated that M. virescens is the same species as M. xanthus. M. virescens was first described in 1892, so has precedence. References External links Model Organism Database John Kirby at the University of Iowa Dale Kaiser Lab at Stanford University Watching social behaviour evolve Taxonomic Information for Myxococcus xanthus Type strain of Myxococcus xanthus at BacDive - the Bacterial Diversity Metadatabase Videos Myxococcus xanthus preying on an E. coli colony Myxococcus xanthus fruiting body formation Myxococcus xanthus ripples – Predation Predatory bacterial crowdsourcing Myxococcota Articles containing video clips Bacteria described in 1941