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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.
In the simplest case of a single locus with two alleles denoted A and a with frequencies f(A) = p and f(a) = q, respectively, the expected genotype frequencies under random mating are f(AA) = p 2 for the AA homozygotes, f(aa) = q 2 for the aa homozygotes, and f(Aa) = 2pq for the heterozygotes.
The level of gene flow among populations can be estimated by observing the dispersal of individuals and recording their reproductive success. [4] [11] This direct method is only suitable for some types of organisms, more often indirect methods are used that infer gene flow by comparing allele frequencies among population samples.
Coalescent theory is a model of how alleles sampled from a population may have originated from a common ancestor.In the simplest case, coalescent theory assumes no recombination, no natural selection, and no gene flow or population structure, meaning that each variant is equally likely to have been passed from one generation to the next.
SPOILERS BELOW—do not scroll any further if you don't want the answer revealed. The New York Times. Today's Wordle Answer for #1274 on Saturday, December 14, 2024.
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.