Fig. 5. The Drosophila ssdp gene and mutant alleles. (A) Schematic drawing of 11 kb of genomic DNA surrounding the ssdp locus. The ssdp gene consists of two exons, the second of which contains the entire protein coding sequence. ssdp is flanked by two predicted genes of unknown function, CG7985 and CG14313. The insertion sites of three P-elements EP(3)3097, l(3)neo48 and EP(3)3004 are shown, as are the boundaries of two deficiency alleles, ssdp^L7 and ssdp^L5, that were generated by imprecise excision of EP(3)3097. (B) Stage of lethality for various allelic combinations of ssdp. Viability of individuals of each genotype was assessed at three stages of development: larval first instar, larval third instar and adult eclosion. (C,D) Newly eclosed adults of the genotype ssdp^EP(3)3097/ssdp^l(3)neo48. Note the blistered wings (arrows in C). Other phenotypes for this allelic combination include a cleft along the midline of the notum (arrowhead in C,D), and/or misshapen, misoriented, deleted or extra macrochaetae on the notum and scutellum (arrow in D). The phenotype shown in D is frequent and relatively mild, compared with rarer individuals in which the cleft was much more severe (not shown).