How organ identity is determined is a fundamental question in developmental biology. In Drosophila , field-specific selector genes, such as eyeless ( ey ) for eyes and vestigial ( vg ) for wings, participate in the determination of imaginal disc-specific identity. We performed gain-of-function screening and identified a gene named winged eye ( wge ), which encodes a bromo-adjacent homology domain protein that localizes at specific sites on chromosomes in a bromo-adjacent homology domain-dependent manner. Overexpression of wge -induced ectopic wings with antero-posterior and dorso-ventral axes in the eye field in a region-specific Hox gene-( Antennapedia ) independent manner. Overexpression of wge was sufficient for ectopic expression of vg in eye discs. A context-dependent requirement of wge was demonstrated for vg expression in wing discs and for expression of eyes absent ( eya ), a control gene for eye development downstream of ey , in eye discs. In contrast to vg , however, overexpression of wge inhibited EY-mediated expression of eya . Consistent with colocalization on polytene chromosomes of WGE and Posterior sex combs (PSC), a Polycomb group gene product, we demonstrated an antagonistic genetic interaction between wge and Psc . These findings suggest that wge functions in the determination of disc-specific identity, downstream of Hox genes.