In a family, the father is affected by a genetic disorder. The son in the family has the same disease, but the daughters do not have it. What type of inheritance is this?

A. Y-linked

B. X-linked

C. polygenic

D. codominant

Answer: Option A Y-linked

Explanation:

Y-linked traits are the ones which are due to the alleles present on the Y chromosome of an organism. Since, only the male members carry the Y chromosome, the traits linked to Y chromosome only pass down from the father to the sons and never to the daughters, such type of inheritance is known as Y linked inheritance. According to the question, the inheritance cannot be X linked because every daughter inherits one X chromosome from the father but the sons only inherit the Y chromosome. Thus, an affected male cannot produce affected sons if the trait is X linked. A polygenic trait is the one whose phenotype is determined by more than one genes, which again is not the case here. A co-dominant trait is the one which is determined by both the alleles i. e the phenotype is determined by both the alleles of a gene and none of the alleles is completely dominant over the other.

As can be seen from the question, the affected father is producing an affected son and no affected daughter, thus this inheritance is Y linked.

the answer is A. Y-linked, i just took the test.