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Genetic drift, also known as random genetic drift, allelic drift or the Wright effect, [1] is the change in the frequency of an existing gene variant in a population due to random chance. [ 2 ] Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation . [ 3 ]
Hence the name "drifty" genes, to contrast the positively selected "thrifty genes". Such drift may have started because around 2 million years ago when ancestral humans effectively removed the risk of predation, which was probably a key factor maintaining the upper boundary of the regulation system.
The drift-barrier hypothesis is an evolutionary hypothesis formulated by Michael Lynch in 2010. [1] It suggests that the perfection of the performance of a trait, in a specific environment, by natural selection will hit a hypothetical barrier.
Neutral drift is the idea that a neutral mutation can spread throughout a population, so that eventually the original allele is lost. A neutral mutation does not bring any fitness advantage or disadvantage to its bearer. The simple case of the Moran process can describe this phenomenon.
Gene flow is the transfer of alleles from one population to another population through immigration of individuals.. In population genetics, gene flow (also known as migration and allele flow) is the transfer of genetic material from one population to another.
Coalescent theory can also be used to model the amount of variation in DNA sequences expected from genetic drift and mutation. This value is termed the mean heterozygosity, represented as ¯. Mean heterozygosity is calculated as the probability of a mutation occurring at a given generation divided by the probability of any "event" at that ...
In population genetics, random walk describes the statistical properties of genetic drift; In physics, random walks are used as simplified models of physical Brownian motion and diffusion such as the random movement of molecules in liquids and gases. See for example diffusion-limited aggregation.
Population size is directly associated with amount of genetic drift, and is the underlying cause of effects like population bottlenecks and the founder effect. [1] Genetic drift is the major source of decrease of genetic diversity within populations which drives fixation and can potentially lead to speciation events. [1]