Question

Sex-linked disorders are generally
A) Lethal
B) Recessive
C) Dominant
D) Not inherited

Answer 1

Hint:Disorders can be either autosomal or sex-linked. Autosomal disorders are caused due to abnormalities in non-sex chromosomes or autosomes. Sex-linked disorders are those associated with any abnormalities associated with either X or Y chromosome which are known as the sex chromosomes.

Complete answer:
Sex-linked disorders can either be X-linked where the X chromosome is affected or Y linked where the Y chromosome is affected. These disorders can either be dominant where both the chromosomes of the pair are affected or recessive where only one chromosome of the pair is affected. In case of an X-linked dominant disorder there is a fifty percent chance that the daughter will inherit the disorder from the affected mother while if it’s a son he has a hundred percent chance of inheriting the disorder. In case of X-linked recessive disorder there is a fifty percent chance that the son will inherit the disorder from the affected mother whereas daughters are most often carriers since they receive a normal copy of X from the healthy father. In case of Y-linked disorders only the sons inherit the disease because the Y chromosome is passed on only to the sons and not to the daughters. But most of the sex-linked disorders are recessive due to the presence of the other functional pair.

Hence the correct answer is option (B) Recessive.

Note: Sex-linked disorders are given more importance than autosomal disorders since they are passed on to future generations giving rise to more complex diseases. So a knowledge about them helps us to treat them in a better way.