Genetic drift is a random change in gene frequency arising Genetic drift through chance alone. It tends to be more apparent in small populations allele frequencies drift away from their starting values, increasing, decreasing or fluctuating up and down. It occurs because there is an element of chance in which individuals and which gametes will produce offspring and which individuals will die before reproducing Random changes in allele frequency can lead to fixation and the progressive loss of genetic variation from the population Genetic When a population undergoes an abrupt contraction in numbers bottleneck this is accompanied by a change in gene frequencies and a decline in the total genetic variation. Genetic drift in the small population during the bottleneck results in the loss of genetic variation. Although population numbers may recover, genetic variation will remain low for many generationsGenetic drift Genetic drift is a random change in gene frequency arising through chance alone. It tends to be more apparent in small populations allele frequencies drift away from their starting values, increasing, decreasing or fluctuating up and down. It occurs because there is an element of chance in which individuals and which gametes will produce offspring and which individuals will die before reproducing. Random changes in allele frequency can lead to fixation and the progressive loss of genetic variation from the population. Genetic bottleneck When a population undergoes an abrupt contraction in numbers, this is accompanied by a change in gene frequencies and a decline in the total genetic variation. Genetic drift in the small population during the bottleneck results in the loss of genetic variation. Although population numbers may recover, genetic variation will remain low for many generations