1) The mini-white in PBac{PB} is flanked by 48-bp FRTs.
2) Upon exposure to FLPase, these efficiently recombine; the mini-white is removed and a single 48-bp FRT is regenerated.
3) The 48-bp FRT is significantly less efficient for longer distance recombination reactions than the longer FRTs commonly used in constructs designed for generation of chromosomal deficiencies.