Curly hair dominates straight hair, and normal pigmentation dominates albinism. Calculate the probability of having

Curly hair dominates straight hair, and normal pigmentation dominates albinism. Calculate the probability of having an albino child with curly hair if the parents are with normal pigmentation and curly hair but are heterozygous.

Let’s designate the gene that causes the development of curly hair as A, then the gene responsible for straight hair will be a.

Let’s designate the gene that causes albinism as b, then the gene responsible for the development of normal skin pigmentation will be B.

Parents, according to the condition of the problem, have curly hair and normal skin color, but are heterozygotes – AaBb. Sperm and eggs produced by parents: AB, ab, aB and Ab.

Possible offspring of a married couple:

children with curly hair and normal skin (AABB, 4AaBb, AaBB, 2AABb, AaBB);

albino children with straight hair (aabb);

children with straight hair and normal skin (2 aaBb, aaBB);

albino children with curly hair (Aabb, 2Aabb).

The resulting phenotypic ratio of 9: 3: 3: 1 suggests that three of the hypothetical 16 children will be albinos with curly hair, which corresponds to 18.75%.

Answer: 18.75%.