Genetic drift is a mechanism of evolution characterized by random fluctuations in the frequency of a particular version of a gene (allele) in a population. It occurs due to chance events, such as the random sampling of alleles for the next generation from the gene pool of the current generation. Genetic drift can cause gene variants to disappear completely and thereby reduce genetic variation, or it could cause initially rare alleles to become much more frequent, and even fixed. Genetic drift usually occurs in smaller populations, and its effects tend to be stronger in small populations. Unlike natural selection, genetic drift is random and does not depend on an alleles beneficial or harmful effects.
Some key points about genetic drift include:
- Genetic drift is one of the basic mechanisms of evolution.
- Genetic drift affects the genetic makeup of the population, but unlike natural selection, it doesn't work to produce adaptations.
- Genetic drift can change allele frequencies in a population, and it happens to all populations.
- Genetic drift can be illustrated with a simplified example of a large colony of bacteria isolated in a drop of solution.
- Genetic draft is an alternative source of stochasticity that affects a locus by selection on linked loci, and its mathematical properties are different from those of genetic drift.
In summary, genetic drift is a random process that can cause changes in the frequency of alleles in a population over time. It is one of the basic mechanisms of evolution and can affect genetic variation in a population.
