Question

Pigmented eyes (P) are dominant to non-pigmented (p), and dimpled chins (D) are dominant to Non-dimpled chins (d). A pigment-eyed, dimple-chinned man marries a blue-eyed woman without a dimpled chin. Their firstborn child is blue-eyed and has a dimpled chin. What are the possible genotypes of the father

Answer 1

Answer:

PpDD and PpDd

Explanation:

Pigmented eyes (P) are dominant to non-pigmented (p), and dimpled chins (D) are dominant to Non-dimpled chins (d).

The possible genotypes of a pigment-eyed, dimple-chinned person would be  PPDD, PpDd, PPDd, PpDD while a blue-eyed person without a dimpled chin would have the genotype ppdd.

The genotype of a blue-eyed, dimpled chin child would be either of ppDd or ppDD, but in this case, the mother is ppdd and as such, the child cannot have two copies of D allele. Hence, the genotype of the child can only be ppDd.

In order for the child to have blue eyes (pp), it means that the father has to have the non-pigmented allele (p). This also means that the father is heterozygous for eye pigmentation (Pp).

Hence, the genotype of the father is now limited to PpDD and PpDd.