In humans, the gene for brown eyes dominates over the gene for blue eyes. A brown-eyed man

In humans, the gene for brown eyes dominates over the gene for blue eyes. A brown-eyed man married a blue-eyed woman from this marriage, 2 brown-eyed sons were born. 1 first son married a blue-eyed woman. 2- on brown-eyed, and they had a blue-eyed son. Determine: 1) the genotype of all family members: 2) the phenotype of the children of 1 son.

Given:

A – brown eye color

a – blue eye color

Decision:

R: AA (father) x aa (mother)

F1: Aa; Aa;

The father and mother are homozygous, so their children are monotonous. Sons are heterozygous, so their offspring will be different.

The first son married a woman with blue eyes. Her genotype is aa.

R: Aa (man) x aa (woman)

F1: Aa; Aa; aa; aa;

The first son will have both blue-eyed and brown-eyed children. In a 2: 2 ratio.

The second son married a woman with brown eyes, i.e. she has the genotype Aa.

She has a gene for blue eyes, since the condition of the problem says that their child is blue-eyed.

R: Aa (man) x Aa (woman)

F1: AA; Aa; Aa; aa;

Genotype: 1: 2: 1

Phenotype: 3: 1