Understanding Genetic Drift: How Chance Shapes Allele Frequencies in Populations

allele frequencies in a population change as a result of random events or chance

genetic drift

Yes, allele frequencies in a population can change as a result of random events or chance. This is known as genetic drift, which is the variation in the relative frequency of different genotypes in a small population, caused by random fluctuations in the number of offspring. The smaller the population, the more effect genetic drift can have on the relative frequency of different alleles.

For example, imagine a population of 100 individuals, with 50 males and 50 females, and a particular gene with two alleles (A and a). If 10 individuals die randomly, and 6 happen to have allele A, the frequency of allele A decreases from 0.5 to 0.44. This change in frequency is not due to any selective advantage or disadvantage of the A allele, but rather just by chance.

Another example of genetic drift is the founder effect, which occurs when a small group of individuals separates from a larger population to establish a new population elsewhere. The new population may have a different allele frequency compared to the larger population, simply because it originated from a small subset of the original population.

Overall, while natural selection is a major factor in shaping allele frequencies in a population by favoring certain traits over others, random events and genetic drift can also play a significant role.

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