Red-green color blindness is due to a mutant gene in the X chromosome. An XX female with normal color vision and an XY male with normal color vision have a child with karyotype XXY who is color blind. The likely explanation is that the:

Question

Quizplus · Accepted Answer

Since the mother is XX and has normal color vision, she must be a carrier for the color blindness gene on one of her X chromosomes. The father, being XY and having normal color vision, does not carry the color blindness gene. The XXY child inherited one X chromosome from the mother and the Y chromosome from the father. Since the X chromosome from the mother carried the color blindness gene, the child is color blind.

Red-Green Color Blindness Is Due to a Mutant Gene in the X