Myopic parents gave birth to a child with normal vision. What is the genotype of the parents?

Myopic parents gave birth to a child with normal vision. What is the genotype of the parents? What other types can there be in this marriage? A – nearsighted a – normal

Since the born child shows a trait that is not manifested in either of the parents, it should be concluded that the inheritance of normal vision is recessive, and that both parents of this child are heterozygous.

Let us write them down, according to the notation introduced in the problem statement, as Aa. The eggs and spermatozoa they produce (each type of germ cell is of two types) will be designated as a and A.

In a marriage of such a man and a woman, the following options may appear:

children suffering from myopia – with a probability of 75% (in this case, 50% of genotypes will be hetero- – Aa; and 25% – homozygotes – AA);

25% will be children with normal visual acuity (aa).