The piggyBac transposon mediates germ-line transformation in the Oriental fruit fly and closely related elements exist in its genome

Germ-line transformation of a white eye strain of the Oriental fruit fly, B actrocera dorsalis, was achieved with the piggyBac vector, derived from a t ransposon originally isolated from the cabbage looper moth, Trichoplusia ni . The Vector was marked with the medfly white(+) gene cDNA, and three trans genic lines were identified at a frequency of approximately 2% per fertile G(0). Vector integrations were verified by Southern DNA hybridization, whic h also revealed the presence of endogenous genomic elements closely related to piggyBac. Approximately 10-20 elements per genome were evident in sever al B. dorsalis strains, and sequence analysis of 1.5 kb gene amplification products from two wild strains and the white eye host strain indicated 95% nucleotide and 92% amino acid sequence identity among resident elements and the T. ni element. PiggyBac was not evident by hybridization in other teph ritid species, or insects previously transformed with the transposon, This is the first discovery of piggyBac beyond T. ni, and its existence in a dis tantly related species has important implications for the practical use of the vector and insects transformed with it.