Some humans have genes that make them resistant to infection by HIV. Would human populations likely evolve differently in areas of the world where HIV infection rates are high? Explain your logic.

Video transcript

Hi everyone. Welcome back. The next question says which of the following, in your opinion is responsible for gradually increasing the genes that confer HIV HIV resistance in human populations in high HIV infection areas over time. Well, let's think about the situation, especially where we have high HIV infection areas. If we have a gene that confers HIV resistance, especially an area with high HIV infection, individuals with that gene are more likely to survive to reproduce and pass on that gene, meaning that over time, as those individuals with the gene are more likely to reproduce, you will see a gradual increase in the prevalence of that gene in the population because this is due to environmental pressure, the presence of a disease that might end someone's life before they could reproduce. So, a gene, the gene that confers resistance causing an increased ability to reproduce. That is the action of natural selection, which is choice. See here, so we have a mutation in this gene that converts resistance, causing increased fitness, increased likelihood to reproduce. So let's look at our other choices here, just to understand why C. Is our answer? Choice says adaptation. An adaptation would be a mutation conferring increased fitness in a given environment. Well, we do have an adaptation adaptation. Being this gene, but that doesn't describe what's responsible for gradually increasing the prevalence of this gene adaptations. The initial change we're looking for, what causes that adaptation to become more prevalent. So choice A. Is not our answer. Choice B. Is genetic drift, genetic drift over here is a variation in the frequency of Jenna types in a small population due to the chance disappearance of some alleles. So there's no selection pressure causing certain aliens to disappear. Certain individuals not to reproduce just by random chance. And because the population so small, um that can occur that can cause the actual disappearance of those alleles. Um So that's not what we're talking about here. So Choice B. Is not our answer. And finally, Choice D fitness for fitness is the likelihood that an individual will survive and reproduce. So this gene for increased HIV resistance does increase the fitness of an organism. But that's talking about what happens in an organism. And we're looking for what will increase the occurrence of those genes and the entire population. So that's not our answer. So, again, what is responsible for gradually increasing the genes that confer HIV resistance in human populations over time choice C. Natural selection. See you in the next video.