A woman with normal vision, whose father suffered from myopia, and whose mother had normal vision

A woman with normal vision, whose father suffered from myopia, and whose mother had normal vision, married a man whose parents were homozygous – a father with normal vision, and a mother with nearsightedness. What offspring are expected in this family if myopia is known to be the dominant trait?

Let’s designate the gene for myopia as A, then the gene that determines the norm of visual acuity will be a.

A woman with normal vision – aa, because only if the genotype is homozygous can one count on the phenotypic realization of a recessive trait. Consequently, she did not inherit the gene for myopia from her father. It only produces eggs as well.

The parents of a man, according to the condition of the problem, are homozygotes, let us write down their genotypes as AA and aa. All children of such a couple will be Aa, which is manifested by the development of myopia.

The short-sighted man Aa produces spermatozoa A and a.

The offspring of this family:

nearsighted children (Aa) – 50%;

children with normal visual acuity (aa) – 50%.