How does insertion or deletion of three or its multiple bases affect the reading frame in DNA?

Step-by-step solution

A classical example of point mutation is a change of single base pair in the gene for beta globin chain that results in the change of amino acid residue glutamate to valine. It results in a diseased condition called sickle cell anemia. Effect of point mutations that inserts or deletes a base in structural genes can be better understood by following simple examples. Insertion or deletion of one or two bases changes the reading frame from the point of insertion or deletion. However, such mutations are referred to as