A transgenic fly that expresses Gal4 specifically in the dorsal (upper) half of the eye. This transgene also expresses the white gene as a marker. This white gene construct is normally expressed in all eye cells, however, in this transgenic fly its expression is silenced in the ventral (lower) half of the eye resulting in the observed adult eye pigmentation pattern. The dorsal eye expression of Gal4 is a useful tool to overexpress UAS-driven transgenes specifically in half the eye. See the paper by Morrison and Halder in this issue.