Question

In humans, normal vision is completely dominant (N) and myopia (nearsightedness) is recessive (n). A homozygous normal female marries a myopic male. What would be the genotypes and phenotypes of the offspring?

Answer 1

The genotypes of the offspring would be heterozygous normal (Nn) since the normal female is homozygous dominant (NN) and the myopic male is homozygous recessive (nn).

The phenotypes of the offspring would depend on whether they inherit a dominant or recessive allele from each parent.

If they inherit a dominant N allele from the mother and a recessive n allele from the father, they would be heterozygous normal (Nn) and have normal vision.

If they inherit a recessive n allele from both parents, they would be homozygous recessive (nn) and have myopia.

Therefore, the offspring would have a 50% chance of having normal vision and a 50% chance of having myopia.