Biology Practice Problems Extensions to Mendel Practice Problems Solution: Your neighbor, a "crazy cat lady", has two white c...

Solution: Your neighbor, a "crazy cat lady", has two white cats with the genotype WwBb. You learned in genetics that the W allele shows dominant epistasis over the B gene, and the B allele (black) is dominant over the b allele (brown). If your neighbor crosses her two white cats, what phenotypic ratio would you expect in the litter? Make sure to include the phenotypes in the ratio.

Problem

Your neighbor, a "crazy cat lady", has two white cats with the genotype WwBb. You learned in genetics that the W allele shows dominant epistasis over the B gene, and the B allele (black) is dominant over the b allele (brown). If your neighbor crosses her two white cats, what phenotypic ratio would you expect in the litter? 

Make sure to include the phenotypes in the ratio.

Solution

If the W gene is epistatic to the B/b gene, the presence of a dominant W allele would mask the pigmentation brought by the B/b gene, leading to white cats. For a cross of WwBb, the Punnet square result would show the following:

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