The 48bp FRT sites that flank the w+mPB.FRT marker in the PBac{PB} element can efficiently recombine in the presence of FLP recombinase, removing the marker and regenerating a single 48bp FRT site. However, the 48bp site is significantly less efficient for longer distance recombination reactions than the longer FRT sites commonly used in constructs designed for generation of chromosomal deficiencies.
A diagram of the PBac{PB} element is available at the [GDP Transposons page](http://flypush.imgen.bcm.tmc.edu/pscreen/transposons.html)
7.257
PBac 5\'
PBac 3\'