Tendency of a gene to vary randomly without the influence of natural selection.
Random fluctuations in the frequencies of certain alleles occurring in small populations.
The tendency for variations to occur in the genetic composition of small isolated inbreeding populations by chance. Such populations become genetically rather different from the original population from which they were derived.
Random fluctuations in gene frequencies can occur within a limited and isolated subset of a population over multiple generations. The likelihood of such random variations becomes more significant as the size of the population decreases. In larger populations, the random transmission of alleles (different forms of a gene at a specific location) tends to even out over time.