Molecular characterization of the White Eye gene of the Oriental fruit fly, Bactrocera dorsalis (Hendel), (Diptera: Tephritidae)

Abstract

The wild-type white eye gene of the oriental fruit fly, B. dorsalis (Hendel), has been cloned and partially sequenced. The 3859 bp DNA sequence includes exons 2, 3, 4a, 4b, 5, and 6, introns 2, 3, 4, 5, and part of intron 1, and the polyA addition site. Compared to the white gene of D. melanogaster, there is an extra intron splitting exon 4 into two exons, 4a and 4b, in the white eye gene of the oriental fruit fly. The corresponding exons in the white eye genes of the two species are similar in size and the phases are the same. The two white eye genes are highly homologous to each other. The coding region sequence of the two genes has similarity of 93% at the amino acid level and 70.8% at the nucleotide level. The inconsistency of the two measures of similarity can be explained by high levels of silent mutation, 71.4%. Silent mutation shows different pattern of codon usage bias in the two white eye genes. D. melanogaster prefers GC base while the oriental fruit fly prefers AT base at the silent sites of the codon.