Genetic Drift | Founder Effect and Bottleneck Effect Explained


thanks for stopping my today we’re going to talk about genetic drift. So genetic drift is a mechanism of evolution that’s responsible for random changes in a gene pool. It happens to all populations but has a much more visible and drastic effect in small populations right it’s driven by chance and not selection so evolutionary Fitness doesn’t matter here it’s all random natural selection doesn’t come into play when we’re looking at genetic drift and there’s two main types of genetic drift you have the founder effect and the bottleneck effect and we’ll look at some examples of both of these. So let’s say that you have a town called Darwinville and you have 100 people that live in this town and those 100 people 95 of them are right-handed and the other five are left-handed let’s say a small group of about four people from this Darwinville decide to move away and settle some new uninhabited land and let’s say these four individuals happen to all be left-handed. Their gene pool is now drastically different from the group they left because all their descendants will be left-handed and this is an example of the founder effect on a small group leaves from a population and carries with it a new gene frequency let’s go back to our town of Darwin ville where we now have 96 people and only one lefty. Let’s say a freak storm comes through and kills 75 of the residents of Darwinville including our last left-handed person and all remaining recessive left-handed alleles. and then the new population now 21 individuals will have no left-handed posterity from this point on so this is an example the bottleneck effect when a random is random reduction of the population due to some random event. So hopefully this video and these examples were helpful you can see the link in the description for more information and for more examples on genetic drift or you can meet up in the comments if you have any questions be sure to check out my other videos and let me know if you have a specific video that you want me to make thanks for watching I’ll catch next time

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