The brown-eyed right-hander married the blue-eyed right-hander. Their first child is left-handed

The brown-eyed right-hander married the blue-eyed right-hander. Their first child is left-handed and has blue eyes. What signs will the further descendants of this pair have?

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

A left-hander with blue eyes, as having both recessive traits, will have the aavv genotype. Homozygosity is a condition under which a recessive trait acquires the ability to be realized in a phenotype.

Then the mother is a carrier of the aaBb genotype, because one of the recessive genes in a pair of her son is inherited from her. Possible mother’s eggs: aB and ab.

A father, a brown-eyed right-hander, can be the parent of a blue-eyed left-hander if he has externally recessive genes in his genotype. Consequently, the father’s genotype is AaBb. Possible spermatozoa of the father: AB, ab, Ab and ab.

In the offspring of this pair, the following options are possible:

brown-eyed right-handed children (AABB, AaBb);

brown-eyed left-handed children (Aabb);

blue-eyed right-handed children (aaBb, aaBB);

blue-eyed left-handed children (aabb).