A brown-eyed man married a blue-eyed woman, they had a blue-eyed child. The gene that determines brown eye color

A brown-eyed man married a blue-eyed woman, they had a blue-eyed child. The gene that determines brown eye color is dominant. Make a scheme for solving the problem. Determine the genotypes of the parents and offspring.

Let’s designate the gene, which is dominant by the condition of the problem, which is responsible for brown-eyed, by the letter “A”. Then the gene responsible for the blue eye color will be “a”.

A blue-eyed child and a woman have the aa genotype, because a recessive trait can manifest itself in a phenotype only if it is homozygous.

Then the brown-eyed father has the Aa genotype, because the second gene from the pair in the child is from the sperm and is inherited from the father.

In the offspring of a couple, brown-eyed and blue-eyed children may appear. Among the probable offspring, the ratio of brown-eyed and blue-eyed children will be 1: 1.