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Title: The ABCs of eye color in Tribolium castaneum: Orthologs of the Drosophila white, scarlet, and brown genes

Author
item Lorenzen, Marce
item Haas, Merrilee - Sue
item Grubbs, Nathaniel - North Carolina State University
item Beeman, Richard

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary: The emerging genome sequence of the pest insect, Tribolium castaneum, contains a wealth of untapped information on the molecular genetic basis of pest biology, and provides an unprecedented opportunity for target discovery and biopesticide development. We are developing tools for manipulation of the Tribolium genome in order to understand gene function, and to home in on candidate target genes for pest control applications. Naturally occurring eye pigments and fluorescent proteins are routinely used as visible markers to select genetically modified strains needed for functional analysis of genes. We have cloned a gene required for eye pigmentation in Tribolium and have determined the genetic basis of a genetic abnormality that blocks the production of this pigment. This discovery will enable this gene to be used for genetic selection in future efforts to determine the functions of pest control genes.

Technical Abstract: In Drosophila melanogaster, three ABC transporters (white, scarlet and brown) are required for normal pigmentation of the compound eye. We have cloned one of the orthologous genes, Tc white (Tcw), from the beetle Tribolium castaneum. Conceptual translation of Tcw reveals that it is 52% identical to the Drosophila white gene. Two eye-color mutations (ivory and pearl) representing different complementation groups were tested for linkage to Tcw via recombinational mapping. Both mutations showed tight linkage with Tcw, suggesting that a second eye-color gene is located in close proximity to Tcw. Molecular analysis of the mutant strains revealed that the Tcw allele of ivory carries a single-base substitution which gives rise to an amino acid change in the highly conserved Walker B motif. Since this amino acid is invariant throughout the animal kingdom, we presume this is the causative mutation and have therefore renamed this mutant strain white ivory (wi).