Penetrance and Expressivity Practice Problems

Waardenburg syndrome is a human autosomal dominant disorder displaying ___________, as individuals with Waardenburg syndrome may have any or all of the four principal features of the syndrome, which include hearing loss, different-colored eyes, a white forelock of hair, and premature graying of hair.

Familial polydactyly is an autosomal dominant trait that is characterized by extra fingers or toes. One of the types of polydactyly is postaxial polydactyly type B, which has a penetrance of approximately 40%. What is the probability of a child being born with polydactyly to parents who are carriers for the trait?

Which of the following is a measure of the percentage of individuals with a given allele who exhibit the phenotype?

In goats, a beard-causing autosomal gene is recessive in females but dominant in males. What is the genetic basis for this trait?

Which of the following accurately defines the term "phenotypic expression"?

_____ is the proportion of animals with a certain genotype that exhibit the phenotype linked to that genotype, whereas the expression level of a given genotype as a phenotype inside an individual is referred to as _____.