Question

Statement 1: Polygenic disorders arise due to mutation in multiple genes
Statement 2: Sickle-cell anaemia is a polygenic disorder

• A. Only statement 2 is true
• B. Only statement 1 is true
• C. Both the statements are false
• D. Both the statements are true

Answer 1

The correct option is B Only statement 1 is true

Polygenic disorder arises due to mutations in multiple genes. Example - diabetes.

Sickle-cell anaemia, on the other hand, is a monogenic disorder which arises due to a mutation in the gene that codes for the beta-globin chain of haemoglobin.

This is a type of point mutation in which there is substitution of a single base pair in the gene that codes for beta globin chain and this results in the change of amino acid. Glutamic acid gets replaced by valine causing RBCs to assume a sickle shape.