Marika's mother has red-green colour blindness, but her father does not.What can we predict about the colour vision of Marika and her three brothers?

Question

Quizplus · Accepted Answer

Red-green color blindness is a sex-linked trait, typically passed on the X chromosome. Since Marika's mother has red-green color blindness, she must have two copies of the gene (as females have two X chromosomes). Marika's father, who does not have color blindness, can only pass on a normal X chromosome to his daughters and a Y chromosome to his sons. Therefore, Marika will receive one normal X chromosome from her father and one X chromosome with the color blindness gene from her mother, making her a carrier but not color blind. Her brothers, however, will inherit the Y chromosome from their father and the X chromosome with the color blindness gene from their mother, making them color blind.

Marika's Mother Has Red-Green Colour Blindness, but Her Father Does