Two parents with widow's peak and short fingers have a child with a continuous hairline and long fingers. What are the genotypes of the two parents? (W = widow's peak; S = short fingers)
A) WWSS × wwss
B) wwss × WWSS
C) WWss × WWss
D) WwSs × WwSs
E) WwSs × wwss

Question

Quizplus · Accepted Answer

- Widow's peak is dominant, so one parent must be heterozygous for the trait and the other parent can either be homozygous recessive or heterozygous. Therefore, the possible genotypes for the parents are: WwSs or WWss.
- Short fingers is also dominant, so one parent must be heterozygous for the trait and the other parent can either be homozygous recessive or heterozygous. Therefore, the possible genotypes for the parents are: WwSs or wwSs.
- The child has a continuous hairline and long fingers, which are both recessive traits. This means that the child must be homozygous recessive for both traits (wwss).
- Combining the possible genotypes of the parents (WwSs and WWss for widow's peak, and WwSs and wwSs for short fingers), the only option that can result in a homozygous recessive child is D: WwSs × WwSs.

Two Parents with Widow's Peak and Short Fingers Have a Child