3. Which of the following is not an X-linked trait?

hemophilia

cystic fibrosis

Duchenne muscular dystrophy

color-blindness

Cystic fibrosis

Explanation:

X - linked trait may be defined as the trait that is located on X chromosome or the inheritance of the trait is based on the X chromosome. The disorders associated with X-linked trait is known as sex linked disorder.

Cystic fibrosis is an autosomal recessive disorder that affects the digestive system, lungs and liver. The homozygous recessive condition is responsible for the disease cystic fibrosis. Hence, cystic fibrosis is not an X-linked trait.

Thus, the correct answer is option (2).