In Drosophila melanogaster, loss-of-function mutations of the bantam locus are lethal at the early pupal stage, whereas hypomorphic combinations of bantam mutant alleles give rise to adult flies that are smaller than controls. Panel (A) shows the reduced body size of male and female flies of banU170/banA1 (defective for bantam), with respect to banA1/TM2 siblings (control). Panel (B) compares wing sizes in both combinations. In the overlay, the banL1170/banA1 wing is shown in red and the banA1/TM2 wing in green.