Question

Evolution of different blood groups occurred due to
A. Genetic variation
B. Genetic drift
C. Both A and B
D. All of the above

Answer 1

There are several blood groups that have been defined based on the antigens located on the surface of RBCs. In addition, such changes happened over a course of time and uniqueness.

Complete answer: Change in the frequency of an existing gene variant in a population due to random sampling of an organism is called genetic drift. Gene variants can be completely disappeared by genetic drift and reduce genetic variation. So, genetic drift is not an appropriate reason for the evolution of different blood groups.
-Differences in DNA among individuals or the differences between the population is called genetic variation. Mutation and genetic recombination are the reason for genetic variation. The ultimate source of genetic variation is a mutation, but sexual reproduction and genetic drift also contribute to it. The existence of different types of blood groups is due to the antigens placed on the surface of RBCs. The determination of blood groups is based on genetic variation.
Thus, the reason for the evolution of different types of blood groups is genetic variation.
Hence, the correct answer is option A

Note: There are two important blood grouping systems. They are as follows: ABO blood group and Rh system. On chromosome 9, a set of three multiple alleles are present which is responsible for the four blood types. They are A, B, AB, and O groups. Only in human and rhesus monkeys, Rh factor is found. The determination of the Rh blood group is based on at least 3 genes located on chromosome 1 each with two alleles.