The random change in the frequency of alleles in a population over successive generations due to sampling error in the gametes. Each new generation differs from its parental generation with regard to allele frequencies simply because of random variation in the distribution of gametes. Over time, this may lead to certain alleles becoming fixed and others being lost altogether. This process is more rapid in smaller populations, following a population bottleneck, or when the alleles concerned confer no apparent benefit compared to their counterparts. Hence, genetic drift can ultimately cause loss of genetic diversity if there are no counteracting factors.