Males are More Often Affected by X-Linked Traits Than Are

Question

Males are more often affected by X-linked traits than are females because ________.
A) imprinting is more likely to occur on X chromosomes inherited from the mother than on Y chromosomes inherited from the father
B) X inactivation occurring in male effectively shuts down expression of any X chromosome genes
C) X chromosomes in males generally have more mutations than X chromosomes in females
D) males are hemizygous genes on the X chromosomes

Accepted Answer

Males have only one X chromosome (and one Y chromosome), making them hemizygous for genes on the X chromosome. This means that if a male inherits a recessive gene on the X chromosome, there is no corresponding gene on a second X chromosome to potentially mask the recessive gene, as would be the case in females who have two X chromosomes. Therefore, males are more often affected by X-linked traits.