Rawlings DE, Tietze E (2001): Comparative Biology of IncQ and IncQ-Like Plasmids
Microbiol. Mol. Biol. Rev. 65: 481-496.

Plasmids belonging to Escherichia coli incompatibility group Q are relatively small in size and able to replicate in a remarkably broad range of bacterial hosts. These include Gram-positive bacteria such as Brevibacterium or Mycobacterium, Gram-negative bacteria like Agrobacterium or Desulfovibrio as well as others, like cyanobacteria. Furthermore, these plasmids are mobilized by several self-transmissible plasmids into an even more diverse range of organisms including bacteria, yeasts and plants. As a result of these properties the IncQ plasmids are highly promiscuous. More recently, several IncQ-like plasmids have been isolated from bacteria found in environments as diverse as piggery manure and highly acidic commercial mineral biooxidation plants. These IncQ-like plasmids belong to different incompatibility groups but have similar broad host-range replicons and mobilization properties as the IncQ plasmids. In the first part of article the diversity and distribution of IncQ and IncQ-like plasmids is reviewed. In the second part, the plasmid backbones, which currently fall into two major groups and several incompatibility subgroups, are compared. In the final part, highly conserved features, the possible evolution as well as evolutionarily constraints of this successful, promiscuous plasmid family are discussed.