- a random change in gene frequency within a small population, resulting in mutations which, regardless of their adaptive value, become fixed within the group
- any such process
The definition of genetic drift is a change in the genes of a group because of the random nature of reproduction.
An example of genetic drift is when only one person in a village has green eyes, but his children do not have the green eye gene and the gene disappears from the population.
Variation in gene frequencies in a population due to chance rather than natural selection, mutation, or immigration.