Genetic drift is a phenomenon that is most significant in small populations. It is the result of the random nature of the process of combining 2 gametes to form a new individual. Imagine a population of 10 individuals with the frequencies of 2 alleles as shown. Assume that these individuals mate randomly with each other, producing 10 offspring. This is equivalent to having a large gamete pool and making 10 random draws from the pool, taking 2 gametes at a time. Because this is a random process, the allele frequencies in generation 2 will probably be different from those in generation 1. In this example, the frequency of the A allele has increased. After another generation of random mating, the allele frequencies will have changed again. In this case, the frequency of the A allele has decreased. Each generation the allele frequency will change up or down from what it was just before. Many generations of genetic drift will inevitably result in the chance elimination of one of the alleles and thus a loss of genetic variation.