Laboratory strains of Escherichia coli: model citizens or deceitful delinquents growing old disgracefully?

Escherichia coli stands unchallenged as biology's premier model organism. However, we propose, equipped with insights from the post-genomic era, a contrary view: that microbiology's chief idol has feet of clay. E. coli laboratory strains, particularly E. coli K-12, are far from model citizens, but instead degenerate and deceitful delinquents growing old disgracefully in our scientific institutions. E. coli K-12 is neither archetype nor ancestor. In addition, it has a far from optimal provenance for a model organism, with strong grounds for believing that current versions of the strain are quite distinct from any original wild-type free-living ancestor. In addition, it is usually studied under conditions far removed from its natural habitats and in ignorance of the selective pressures that have shaped its evolution. Fortunately, a flood of information from high-throughput genome sequencing, together with a new 'eco-evo' view of this model organism, promises to help put K-12 better into context.