Question

If a trait is only passed along from a mother to her son, the mode of inheritance is most likely

• A. Autosomal dominant
• B. Autosomal recessive
• C. Y-linked
• D. X-linked
• E. Codominant

Answer 1

The correct option is D X-linked

A. Autosomal dominant trait is inherited in each generation of family.

B. Autosomal recessive trait is inherited when two copies of the autosome carrying the allele for that particular trait is present in the same individual.

C. Y-linked trait is inherited only in males as the allele for that particular trait is present on the Y chromosome.

D. X-linked trait is inherited by X chromosome. If the trait is X-linked recessive trait then it occurs frequently in males because they have only one X chromosome.

E. Codominance is a condition in which F1 hybrid does not show the characters of either of the parents, instead, is a mixture of two.

Hence, if a mother is affected and she is passing the trait to her son, this means the X-linked recessive because the mother has two chromosomes, one of which will be passed to her son and will show the trait in him.

So, the correct answer is 'X-linked'.