Most individuals who have X-linked diseases are males because
A) males have only one copy of the X chromosome.
B) the diseases are triggered by the male sex hormone, testosterone.
C) males have an extra Y chromosome.
D) males have an extra X chromosome, making them XXY.

Question

Quizplus · Accepted Answer

X-linked diseases are caused by mutations on genes located on the X chromosome. Females have two copies of the X chromosome, so if they inherit a mutant X chromosome, they have a second normal X chromosome to compensate. However, males only have one X chromosome, so if they inherit a mutant X chromosome, there is no second X chromosome to compensate. This is why X-linked diseases are more commonly observed in males.

Most Individuals Who Have X-Linked Diseases Are Males Because