Table 2.

Rescue of double-mutant lethality by a wild-type transgene of dx, e(r) or N

Genotype tested	Heterozygous females	Hemizygous tester males
Nnd-p e(r)p2; Tr[e(r)+]SS	467	205
Nnd-p e(r)37-6; Tr[e(r)+]SS	359	159
dx e(r)27-1; Tr[e(r)+]SS	95	71
Nnd-p e(r)37-6; Dp(1;3)DC109	130	70
dx e(r)27-1; Dp(1;3)DC157	166	118
dx e(r)27-1; Dp(1;3)DC109	173	57

Females that were heterozygous for the double-mutant combination were crossed to males that were homozygous for a transformation construct carrying the wild-type allele of either dx, e(r) or N. Each of the three transgenes is located on the third chromosome. As in Table 1, viability was measured as the number of hemizygous males vs. the number of heterozygous sisters as a control. All individuals were heterozygous for one of the transgene constructs (for dx - Dp(1;3)DC157, for e(r) - Tr[e(r)⁺]^SS, or for N - Dp(1;3)DC109. Rescue was seen as the presence of hemizygous males. Compare these results to those in the absence of the transgene (Table 1). Note that the lethality of the e(r) N^nd-p double mutants is rescued by either an e(r) or a N transgene and that the lethality of the e(r) dx double mutant is resculed by either an e(r) or a dx transgene. Also note that the lethality of the e(r) dx double mutant is also rescued by a N transgene, which argues that the lethality is caused by a decrease in N expression.