An undesired, unexpected sudden change in the gene for beta globin chain that results in the change of amino acid residue glutamate to valine is a classic example of:

A classic 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 into a diseased condition called as sickle cell anaemia. In sickle celled anaemia GAG is mutated to GTG and therefore it is transversion types of mutation. (Purine changed to pyrimidine)