... a Drosophila genetics tool. The piggyBac transposon inserts randomly into TTAA ... in the target genome. Traditionally, piggyBac is used in gene-trap ... with gene-trap vectors and piggyBac transposase, which catalyzes transposon insertion....-expressing mice with mice carrying piggyBac gene-trap alleles in Mdc1 ... Therefore, Cre-mediated recombination of piggyBac-inserted loxP sites mutates large ...