Originally, S. invicta was believed to be a red form of the black species S. saevissima richteri Forel. In 1972, Buren described the black imported fire ant to be a separate and distinct species, S. richteri Forel, and the RIFA was identified as S. invicta Buren (Hedges 1997).
Homologous recombination is a type of genetic recombination in which nucleotide (molecules which are joined make the structural units of RNA and DNA) sequences are exchanged between two similar or identical molecules of DNA.
1 Homologous recombination has been most studied and is best understood for E.coli, a type of bacteria.  RecBCD pathway: The RecBCD pathway is the main recombination pathway used in bacteria to repair double strand breaks in DNA. These double strands can be caused by ultra violet light and other radiation.