A blue-eyed mother and a brown-eyed father had a brown-eyed son and a blue-eyed daughter

A blue-eyed mother and a brown-eyed father had a brown-eyed son and a blue-eyed daughter to determine the genotype of parents and children.

It is a well-known fact that blue-eyed is a recessive trait. Let’s designate the gene that determines the development of blue eyes as c. The gene for the development of brown eyes – like C.

A blue-eyed mother would be written cc because homozygosity is required for the phenotypic realization of the blue iris color. Such a woman produces eggs of the same type – p.

Blue-eyed daughter, like mother – ss. She receives half of the genetic information from her father, who, being brown-eyed, must carry the gene for blue eyes in his genotype. Consequently, the father is heterozygous. We write it as Cc, and the sperm produced by it – c and C.

All hypothetical variants of the offspring of this family will look like this:

brown-eyed children – heterozygotes (Cc) – 50%;

blue-eyed children – homozygotes for the gene for the recessive trait (cc) – 50%.