TRANSVECTION AT THE EYES ABSENT GENE OF DROSOPHILA

The Drosophila eyes absent (eya) gene is required for survival and dif ferentiation of eye progenitor cells. Loss of gene function in the eye results in reduction or absence of the adult compound eye. Certain co mbinations of eya alleles undergo partial complementation, with dramat ic restoration of eye size. This interaction is sensitive to the relat ive positions of the true alleles in the genome; rearrangements predic ted to disrupt pairing of chromosomal homologs in the eya region disru pt complementation. Ten X-ray-induced rearrangements that suppress the interaction obey the same general rules as those that disrupt transve ction at the bithorax complex and the decapentaplegic gene. Moreover, like transvection in those cases, the interaction at eya depends on th e presence of normal zeste function. The discovery of transvection at eya suggests that transvection interactions of this type may be more p revalent than generally thought.