Question

What is meant by genetic drift? What is the notion of genetic drift?

Answer 1

Genetic drift is a phenomenon that occurs in small populations. Here, there is a change in frequency of a gene or genes, due to a random event or chance when there is disappearance of certain part of population, or when reproduction does not take place.
The notion of genetic drift is that certain accidents can alter the frequency of some genes of a small population, even if they don't provide any survival advantage.