A recessive allele on the X chromosome causes color deficiency. A color-deficient boy has a mother with normal vision and a color-deficient father. From which parent did he get the color-deficiency gene?
A) Either mother or father
B) Mother
C) Father

Question

Quizplus · Accepted Answer

The boy must have inherited the X chromosome carrying the color deficiency allele from his mother, as males inherit their single X chromosome from their mothers and the Y chromosome from their fathers. The father cannot pass an X chromosome to his sons, only to his daughters.

A Recessive Allele on the X Chromosome Causes Color Deficiency