Albenism in humans is inherited as a recessive trait. In a family where one of the spouses is albino

Albenism in humans is inherited as a recessive trait. In a family where one of the spouses is albino and the other has normal pigmentation, the first child has normal pigment development and the second has albinos. Determine the genotypes of the parents and two children. What is the probability of having a third child healthy?

Let’s designate the gene that determines the development of albinism in humans as c, then the gene that causes the development of normal pigmentation will be designated as C.

A born albino child has a genotype homozygous for the recessive gene – cc. From both parents, he should have inherited the albinism gene c, therefore, his parent who has normal pigmentation is heterozygous – Cc. The albino parent, like this child, is ss.

The heterozygous parent produces two types of germ cells – C and c.

A parent with cc albinism produces the same type of germ cells c.

For this pair, the following offspring options are possible:

50% – heterozygous children with normal pigmentation (Cc);

50% – children homozygous for the albinism gene, suffering from this pathology (cc).

Answer: the probability of having a third child healthy in this family is 50%.