Genetic diversity in living human populations is highest in Afric...

Question

Genetic diversity in living human populations is highest in Africa and decreases as a function of distance traveled by the human migration that left Africa many millennia ago. Draw a graph to show this trend. (Hint: What is the independent variable? What is the dependent variable? What kind of graph is appropriate for this kind of data? Add a label where you would expect to find a data point for the Yanomamö tribe of the Amazon rain forest in South America. Why is it important to use indigenous people for this study?

Accepted Answer

Welcome back. Here's our next problem, Africa has a higher degree of human genetic diversity than any other continent. This is consistent with the theory that modern humans of their origin in Africa. A small part of the population migrated out of Africa and reached new locations where they established their own population with lower genetic variability. This is an example of the, let's look through our answer choices and see what makes sense. Choice. A says founder effect. Well, the founder effect that over here is when you have a loss of genetic variation, when a new population is established by a very small group from a larger population. And this loss of genetic variation is because the group that that founds the new population is so small that it represents only a small portion of the alleys that are present in a large population that it came from. So this is indeed what this problem is describing a very small part of the large population in Africa, migrated out of Africa, formed new populations, but then they lost some of the alls that were present in the original large population. So that loss of genetic variability as a result of this is the founder effect. So choice A is correct. Let's just walk through the other answer choices to understand why they are not the answer. Choice B is Alo Patrick speciation. Uh This is speciation that results um when species are geographically separated from each other with barriers that aren't crossed. Um So I put geographic and this is not the case here. Uh because although the populations eventually they were spread out, they weren't separated because this population migrated from Africa to the new areas. So there was no, there wasn't a point at which there was a barrier preventing gene exchange between the two groups to c says bottleneck effect. Uh bottleneck effect occurs when you have a drastic reduction in population due to disaster. So you lose genetic variation because your population suddenly drastically decreased, had a massive um die off because you had some sort of giant disaster, a volcano or plague or something. But that isn't what happened. You just had this small group migrating away. So choice C is not our answer. And then finally, choice D natural selection. Well, natural selection is just that process where different genes are selected for or against because they give an advantage or disadvantage to the individuals that have those genes in terms of being able to survive and reproduce. So that isn't what caused the loss of genetic variation here. So choice D is not our answer. So again, uh this example, the small part of the population migrating out of Africa, reaching new locations where they establish their own population with lower genetic variability is an example of the choice, a founder effect. See you in the next video.

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