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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.
Simplified phylogeny of Homo sapiens for the last two million years. Genetic evidence suggests that a species dubbed Homo heidelbergensis is the last common ancestor of Neanderthals, Denisovans, and Homo sapiens. This common ancestor lived between 600,000 and 750,000 years ago, likely in either Europe or Africa.
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.
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.
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Genetic drift allows a locally adapted subpopulation to move across an adaptive valley to the base of a higher adaptive peak. Natural selection will move the subpopulation up the higher peak. This new superiorly adapted subpopulation may then expand its range and outcompete or interbreed with other subpopulations, causing the spread of new ...