In humans, a widow's peak is caused by a dominant allele (W), and a continuous hairline is caused by a recessive allele (w).Short fingers are caused by a dominant allele (S), and long fingers are caused by a recessive allele (s).Suppose a woman with a continuous hairline and short fingers and a man with a widow's peak and long fingers have three children.One child has a widow's peak and short fingers, one has a widow's peak and long fingers, and one has a continuous hairline and long fingers.What are the genotypes of the parents?
A) Female wwSS; male WWss
B) Female wwSs; male Wwss
C) Female wwSs; male WWss
D) Female WwSs; male WwSs
E) Female WwSs; male WWss

Question

Quizplus · Accepted Answer

The woman must have the genotype wwSs because she expresses the recessive traits for hairline (continuous, requiring two recessive alleles, ww) and the dominant trait for finger length (short fingers, indicating at least one dominant allele, S). The man must have the genotype Wwss because he expresses the dominant trait for hairline (widow's peak, requiring at least one dominant allele, W) and the recessive trait for finger length (long fingers, requiring two recessive alleles, ss). The variety in their children's phenotypes further supports these genotypes, allowing for all observed combinations of traits.

In Humans, a Widow's Peak Is Caused by a Dominant