Question

In man, hitchhiker's thumb is domiant to a straight thumb, and brown eyes is dominat to blue eyes. If a man that has a straight thumb and brown eyes in the heterozygous form marries a woman that is heterozygous for hitchhiker's thumb and blue eyes, what is the chance that one of their children will have a straight thumb and blue eyes?

Answer 1

Answer:

25%

Explanation:

T = Hitchhiker's thumb

t = straight thumb

B = Brown eyes

b = blue eyes

The man's genotype is ttBb

The woman's genotype is Ttbb

Make a dihybrid punnett square to find the possible genotypes of the offspring

ttbb is straight thumb and blue eyes. There are 4 out of 16 genotypes with this phenotype so:

Divide 4 with 16 and multiply by 100 to get the percentage of offspring with that phenotype

4 ÷ 16 = 0.25

0.25 × 100 = 25%