THE WHITE GENE OF THE TEPHRITID FRUIT-FLY BACTROCERA-TRYONI IS CHARACTERIZED BY A LONG UNTRANSLATED-5'-LEADER AND A 12 KB FIRST INTRON

A 300 bp fragment from exon 6 of the white gene of Bactrocera tryoni w as used to screen a B. tryoni genomic library. One positive (similar t o 14 kb) insert contained exons 2-6 of white by nucleotide and amino a cid 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 P CR fragment of genomic DNA was generated, containing the exon 1 coding region plus similar to 2.1 kb of upstream sequence, encompassing the putative promoter of the gene, Exon 1 was found to be 728 bp long, enc oding the first twenty-five amino acids, The full length of intron 1 w as shown to be 12 kb (amplified using long PCR protocols), up to 3 tim es the length of the longest white intron 1 isolated to date.