A 300 bp fragment from exon 6 of the white gene of Bactrocera tryoni was used to screen a B. tryoni genomic library. One positive (approximately 14 kb) insert contained exons 2-6 of white by nucleotide and amino acid sequence similarity to the white genes of D. melanogaster (O'Hare et al., 1984; Pepling & Mount, 1990). Lucilia cuprina (Garcia et al., 1996). Ceratitis capitata (Zwiebel et al., 1995) and Anopheles gambiae (Besansky et al., 1995). A white 5' cDNA fragment containing exons 1, 2 and part of exon 3 was amplified, cloned and sequenced. An inverse PCR fragment of genomic DNA was generated, containing the exon 1 coding region plus approximately 2.1 kb of upstream sequence, encompassing the putative promoter of the gene. Exon 1 was found to be 728 bp long, encoding the first twenty-five amino acids. The full length of intron 1 was shown to be 12 kb (amplified using long PCR protocols), up to 3 times the length of the longest white intron 1 isolated to date.