Position of the DACK gene. (Top) Chromosomal in situ hybridization with DACK genomic probe done on a Df(3L)C175/+ larva, showing signal at 64AB on only one chromosome. (Bottom) Diagram of DACK genomic region. Characterized transcription units and those predicted by the BDGP are shown as arrows. The positions of two P-element insertions are indicated by triangles. The position of the l(3)S137212 insertion was determined in this study, and the lethality associated with this insertion was assigned to the l(3)64Ab complementation group. An expanded view of the DACK transcription unit is shown at the top of the diagram. Exons are shown as boxes, introns are shown as triangles, and the open reading frame is in black. The bottom of the figure shows the breakpoints of two deficiencies, Df(3L)C175 and Df(3L)H298, with the sequences removed by the deficiencies indicated by open spaces. Dashed horizontal lines indicate uncertainty in the breakpoints. The five lethal complementation groups uncovered by Df(3L)C175 are listed, together with the genes to which they have been assigned.