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By: Nuor Nofal
Genetic Drift
Genetic Drift is a mechanism of evolution in which allele frequencies of a population change over generations due to chance of events or "sampling error". This error works to select the alleles for the next generation from the gene pool of the current generation. Although genetic drift happens in populations of all sizes, its effects tend to be stronger in small populations
There are two forms of genetic drift:
1. Founder Effect -
2. Bottleneck Effect -
An extreme example of genetic drift that happens when the size of a population is severely reduced. Events like natural disasters (earthquakes, floods, fires) can decimate a population, killing most indviduals and leaving behind a small, random assortment of survivors.
The allele frequencies in this group may be very different from those of the population prior to the event, and some alleles may be missing entirely. The smaller population will also be more susceptible to the effects of genetic drift for generations (until its numbers return to normal), potentially causing even more alleles to be lost.
when a small group of individuals breaks off from a larger population to establish a colony. The new colony is isolated from the original population, and the founding individuals may not represent the full genetic diversity of the original population. Alleles in the founding population may present at different frequencies that in the original population, and some may be missing altogether. Occurs due to colonization.
Watch the video to hear more on the to types of genetic drift
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