Figure 4.

Reporter gene expression of the Malpighian tubule-specific construct in females (a, c) and males (b, d) in whole fly and in carcass. Within each sex, each bar represents a transformed line with the reporter gene inserted at a unique autosomal (dark) or X-linked (light) location. The white bar indicates the activity of the control yw (non-transgenic) strain. The transformed lines are presented in the same order in all panels. Expression was measured spectrophotometrically as β-galactosidase activity in units of mOD min⁻¹. Error bars indicate the standard deviation across biological replicates. Dotted lines indicate the average activities of all autosomal or X-linked lines within each sex. There was not a significant difference between autosomal and X-linked expression for either sex in whole flies (Wilcoxon's test; P=0.21 for females, P=0.82 for males) or in carcasses (P=0.89 for females, P=0.49 for males). However, in whole flies male expression was significantly higher than female expression on both the autosomes (Wilcoxon's signed-rank test, P=0.012) and the X chromosome (P=0.031).