The classical example of point mutation is

Step-by-step solution

Sickle cell anaemia is the classical example of a point mutation. It is caused by the substitution of a single nitrogenous base (GAG GUG) at the sixth codon of the -globin chain of the haemoglobin molecule. This single base substitution leads to the replacement of glutamic acid by valine at the sixth position of the -globin chain, resulting in the sickle shape of red blood cells under low oxygen tension. Answer: Sickle cell anaemia