Chapter 9, Problem 7PDQ

In Lymnaea, what results would you expect in a cross between a Dd dextrally coiled and a Dd sinistrally coiled snail, assuming cross-fertilization occurs as shown in Figure 9.11? What results would occur if the Dd dextral produced only eggs and the Dd sinistral produced only sperm?

FIGURE 9.11 Inheritance of coiling in the snail Lymnaea peregra. Coiling is either dextral (right-handed) or sinistral (left-handed). A maternal effect is evident in generations II and III, where the genotype of the maternal parent rather than the offspring’s own genotype, controls the phenotype of the offspring. The photograph illustrates right-versus left-handed coiled snails.