In Lymnaea a Dd dextrally coiled snail and a Dd sinistrally

In Lymnaea, a Dd dextrally coiled snail and a Dd sinistrally coiled snail were crossed, as shown in Figure 9-11.

a)

What are the phenotypes of the offspring?

What are the phenotypes of the offspring?

unknown

b)

If the Dd dextral produced only eggs and the Dd sinistral produced only sperm, what offspring phenotypes would result?

dextral

sinistral

3 dextral : 1 sinistral

unknown b) If the Dd dextral produced only eggs and the Dd sinistral produced only sperm, what offspring phenotypes would result? sinistral unknown dextral 3 dextral : 1 sinistral

Generation I dextral DD Cross- fertilization Degg X d sperm dextral Generation II Self fertilization Generation I DD Dd Dd dd All dextral Self-fertilization Generation IV sinistral dextral dd sinistral D sperm x degg sinistral dd All dextral dextral sinistral Pearson Education, Inc.

Solution

The first has been answered in the diagram itself.

Ans (b) if Dd dextral produce only eggs and Dd sinistral produce sperms, then phenotype of offsprings would be dextral because the pattern is shows maternal genotype effect.