A man with a widow's peak (dominant)and can curl his tongue (dominant)has a child who has a continuous hairline and cannot curl the tongue.What is the genotype of the father?
A)WWTT
B)wwtt
C)WwTt
D)Wwtt
E)WT

Question

Quizplus · Accepted Answer

- Widow's peak is a dominant trait, so the father must have at least one dominant allele for the trait. We denote dominant alleles with a capital letter, so we can represent the father's alleles for this trait as either WW or Ww.
- The ability to curl the tongue is also a dominant trait, so the father must have at least one dominant allele for this trait as well. We can represent this allele as T.
- The child has a continuous hairline (recessive trait) and cannot curl their tongue (recessive trait), so they must have received two recessive alleles for both of these traits. We denote recessive alleles with a lowercase letter, so the child's alleles for these traits are ww and tt.
- We know that the father must have passed on one allele for each trait, so we can set up a Punnett square to see the possible combinations:

|   | W  | w  |
|---|---|---|
| T | WT | wT |
| t | Wt | wt |

- Each of these combinations is equally likely, so we need to consider all of them. The only combination that matches the child's traits is Wwtt, so the father's genotype must be WwTt.

A Man with a Widow's Peak (Dominant)and Can Curl His