white
The white gene encodes a membrane transporter belonging to the ATP-binding cassette (ABC) transporter superfamily. The membrane transporter superfamily shares common features such as ATP-binding motifs A and B, a signature sequence, and transmembrane-spanning regions. The gene product of white is responsible for importation of eye pigment precursors (including guanine and tryptophan) into pigment cells in cooperation with other transporters. Defects in the white gene product prevent successful transport of pigment precursors into the eye and results in a colorless (white) eye phenotype.
White complete coding sequences have been obtained for several insects including Ceratitis capitata (Zwiebel et al. 1995, Gomulski et al. 2001; Genbank accession number X89933), Lucilia cuprina (Garcia et al. 1996; Genbank accession number U38899), Drosophila melanogaster (Pepling & Mount 1990;Genbank accession number X51749), Aedes aegypti (Coates et al. 1997; Genbank accession number U88851), Anopheles gambiae (Besansky et al. 1995; Genbank accession number U29486), Bombyx mori (Abraham et al. 2000; Genbank accession number AF229609), and Athalia rosae (Sumitani et al. 2005; Genbank accession number AB191788). In Athalia rosae (the only fully characterized sequence for a member of the Hymenoptera), the gene consists of 11 exons separated by 10 relatively short introns (Fig. 1 in Sumitani et al. 2005). Zwiebel et al. 1995 provide a map which identifies the transmembrane-spanning domains.
White has been used in several phylogenetic studies of insects including mosquitoes (Besansky & Fahey 1997, Krzywinski et al. 2001) and diopsid (stalk-eyed) flies (Baker et al. 2001). The gene shows substantial variation in intron presence absence within and among lineages of mosquitoes (Krzywinski & Besansky 2002). The complete sequence of a sawfly (Athalia rosae; Sumitani et al. 2005) allowed us to identify the Apis mellifera white gene using the honey bee genome. We developed primers that span an approximately 1500 bp region of the white gene in bees including exons III to VII.
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Gene Information: |
white primer information (.pdf file) |
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