Fig. 3.

Design and outcomes of the mutagenesis test for (de)canalization. (A) The crossing scheme for mutagenized flies is depicted, including the three major chromosome pairs of Drosophila. Colored chromosomes highlight potential modes of inheritance leading to observable recessive mutations in F2 males and F3 flies of either sex (only a subset of potential genotypes are depicted). The observed frequencies of wing vein defects are then shown for each tested inbred strain for (B) F2 males and (C) F3 females. The large excess of de novo wing mutants for Ethiopian strains indicates reduced canalization of wing development relative to Zambian strains. *Number of segregating inversions detected within each inbred strain.