The brown-eyed right-hander married the blue-eyed right-hander. they had two children: a brown-eyed left-hander

The brown-eyed right-hander married the blue-eyed right-hander. they had two children: a brown-eyed left-hander and a blue-eyed right-hander. determine the probability of birth in this family of blue-eyed left-handers.

Let’s designate brown-eyed as “A”, right-handedness as “B”, then blue-eyed will be designated “a”, left-handedness – “b”.

Children, a brown-eyed left-hander (A_bb) and a blue-eyed right-hander (aaB_), who inherited one recessive gene from both parents, indicate that a brown-eyed man is heterozygous for eye color, and a right-handed woman – for the type of lateralization of the brain centers (responsible for the leading hand ). Therefore, the woman is aaBb, the man is AaBb.

Egg cells of a woman: AB and AB. Male spermatozoa: AB, AB, AB and AB.

Possible genotypes of children: AaBB, aaBB, 2 * AaBb, 2 * aaBb, Aabb, aabb.

Blue-eyed left-handers (aavv) can be born with a probability of 7: 1, or (1 * 100%) / 8 = 12.5%.