FLPm6 is an engineered variant of the FLP recombinase encoded by the Saccharomyces cerevisiae 2μ plasmid, containing the mutations G5D, A36T, T50A, K82Y, G109N, E150G and R281V relative to FLPG5 (FBrf0213120). The target-site specificity of this variant is altered compared to wild-type FLP recombinase, such that FLPm6 is largely only compatible with the mFRT11-71 target site, a derivative of FRT that contains mutations in its inverted repeats (FBrf0213120, PMID:12547191). FLPm6 mediates recombination between a pair of mFRT11-71 sites. The recombination event results in genetic modification, the nature of which is influenced by the relative orientation (direct or inverted), location and composition of the two target sites. The types of possible modification include deletion of DNA, generation of chromosomal rearrangements and integration of DNA into the genome (reviewed in FBrf0231034).

The recombination efficiency of the FLPm6-mFRT11 pair in an in vivo excision assay is only approximately one-fifth of the recombination efficiency of wild-type FLP towards the FRT site.