A blue-eyed right-hander whose father was left-handed marries a brown-eyed left-hander from a family all of whose members have had brown eyes for generations. What offspring and with what probability in relation to these two traits should be expected from this marriage?
Let’s designate the gene that determines the priority of the right hand over the left in a person will be K, then left-handedness will be determined by the gene in the homozygous genotype, designated k.
Let the gene that determines the development of blue eyes in humans, provided the genotype is homozygous for it, be designated m, then the gene for brown eyes will be designated M.
The boy’s father was left-handed, therefore, he possessed a homozygous kk genotype for this trait and could only pass on the left-handed gene to his son. Consequently, the young man is heterozygous for the dominant hand.
The young man has the mmKk genotype and produces two types of spermatozoa – mK and mk.
The girl is most likely homozygous for the dominant gene for eye color and has the Mmkk genotype. It produces two types of oocytes – Mk and mk.
The offspring of this married couple will be formed by the following possible options:
brown-eyed children with a dominant right hand (MmKk) – 25%;
blue-eyed children with a dominant right hand (mmKk) – 25%;
brown-eyed children with a dominant left hand (Mmkk) – 25%;
blue-eyed children with a dominant left hand (mmkk) – 25%.