A blue-eyed brunette married a brown-eyed blonde. What kind of children can be born if both parents are heterozygous?

As a rule, in humans, the brown color of the iris of the eyes dominates over blue, and hair of dark shades over hair of light shades.

Let’s designate the gene that causes the development of the brown color of the iris in humans as K, and the gene for the blue color of the iris as k.

Let’s designate the gene for dark hair shades as L, and for light shades as l.

According to the condition of the problem, the parents are heterozygous. They can be heterozygous only for those traits by which they demonstrate the dominant traits in the phenotype.

A father with dark hair and blue eyes will have, according to the introduced designations and the condition of the problem, the kkLl genotype. Such a man is capable of producing two types of sperm – kl, kL.

The mother, with brown eyes and blonde hair, has the Kkll genotype. It also produces eggs of two types – Kl, kl.

The offspring of this married couple will be represented by the following possible options:

children with dark hair and brown irises (KkLl) – 25%;

children with dark hair and blue irises (kkLl) – 25%;

children with blond hair and brown irises (Kkll) – 25%;

children with light hair and blue irises (kkll) – 25%.