A blue-eyed man, both of whose parents had brown eyes, married a brown-eyed woman whose father

A blue-eyed man, both of whose parents had brown eyes, married a brown-eyed woman whose father had brown eyes and whose mother had blue eyes. From this marriage, a blue-eyed child was born. Determine the genotypes of all the persons mentioned.

In humans, the gene for brown eyes dominates over the gene for blue eyes. Let A – brown eyes, then a – blue eyes.

1. A recessive trait manifests itself only in a homozygous state, which means the genotype of a blue-eyed man is aa, and his dark-eyed parents were heterozygous, that is, Aa.

2. The woman he married has brown eyes, but her father was blue-eyed, which means she will also be heterozygous – Aa.

3. They had a blue-eyed child, which means his genotype is the same as that of his father – aa.