Figure 1.

(A) Crossing scheme to generate backcross pupae segregating for whole chromosomes. D. americana (A) and D. virilis (V) chromosomes are shown in brown and black, respectively. Female genotypes are shown on the left and male genotypes on the right. For each hybrid the genotype notation is abbreviated and the maternal allele is indicated first. The pupal color phenotype for pure species and hybrids is shown next to the pure species and F1 karyotypes. Eight possible genotypes (four female and four male) are illustrated for backcross hybrids. (B) Associations between chromosomal genotypes and pupal color phenotype among whole-chromosome backcross hybrids. The proportion of the two alternative whole-chromosome genotypes for red/brown and black backcross pupae is plotted for each autosomal linkage group. The sum of A/V and V/V genotypes for each phenotypic class within each chromosome should be 1.