Recombinases classification by function
Prokaryotic site specific inversion systems
These invertases can be endogenous (Hin or Fim) or encoded by phages genomes (Gin,Cin). DNA inversions generate diversity in the population. It is a mean to pre-adapt a portion of the population to a sudden change in in the environment, giving a benefit to this subpopulation and allowing specie survival in particular cases. Sometimes, inversion is also triggered by an environemental signal. DNA inversion can produce different outcomes, the simpler being the differential expression of two genes giving two heritable traits. More complicated systems exist however, which can generate multiple DNA isoforms, like plasmid shufflons (mycoplasma). DNA inversion control gene expression by switching the gene coding sequence, the promoter, or both.