Males are More Often Affected by Sex-Linked Traits Than Females

Question

Males are more often affected by sex-linked traits than females because
A) male hormones such as testosterone often alter the effects of mutations on the X chromosome.
B) female hormones such as estrogen often compensate for the effects of mutations on the X chromosome.
C) X chromosomes in males generally have more mutations than X chromosomes in females.
D) males are hemizygous for the X chromosome.
E) mutations on the Y chromosome often worsen the effects of X-linked mutations.

Accepted Answer

Males have one X and one Y chromosome, while females have two X chromosomes. Therefore, males are hemizygous for the X chromosome, meaning that any mutation on their X chromosome will be fully expressed as they lack a second X chromosome to provide a functional version of the gene. In contrast, females have two copies of the X chromosome, so they may have a functional copy to compensate for any mutations on the other X chromosome.