Answer:
Random changes in specific trait of a given small population
Step-by-step explanation:
Genetic drift is a phenomenon which is more specific in population of small size. Usually under the genetic drift effect , a population with a specific trait tries to reproduce with population that has no such traits and hence, in long run the resulting population eventually loses this specific trait.
Thus, genetic drift causes loss of alleles that are rare and also reduces the size of gene pool. The new population is genetically distinct than the original population.