In this example, we're going to be using Hardy Weinberg and then graphing our results. It says here the table below gives the allele frequencies. Remember that's p and q for 4 populations that we've named populations a, b, c, and d. Importantly, these populations are in Hardy Weinberg. Alright.
So based on the information, we want to fill in the values for p2, q2, and 2pq. Then using the graph, we want to plot the genotype frequencies for populations a, b, c, and d. So let's get going. We see here we have allele frequencies p and q. Going down in the columns and going across, we have these populations a, b, c, and d. We want to figure out the genotype frequencies. That's p2 or the frequency of that first homozygote, 2pq or the frequency of the heterozygote, and q2 for the frequency of that second homozygote. So we can do this really quickly, right? P equals 0.
Well, what’s p2 equal then? Well, 0 squared is 0. 2pq is going to be 0 times 1 times 2 or 2 times 1 times 0 is going to be 0. And q2, well, we're just going to take 1 squared and that equals 1. Alright.
For our next one, population b p2, well, we're going to take 0.2 square that, that equals 0.04. 2pq is going to be 0.2 times 0.8 times 2 is going to be 0.32. And q2 0.8 squared that equals 0.64. All right, so now for population c, well 0.4 squared for p2 that equals 0.16, 2pq 2 times 0.4 times 0.6 equals 0.48, and q2 0.6 squared equals 0.36 and our final one here population d, they're at 0.5 and 0.5. So p2 equals 0.5 Squared which is 0.25.
That's also what q equals. So that's 0.25 and 2 times 0.5 times 0.5 equals 0.5. Alright. So we've filled in our genotype frequencies, our predicted genotype frequencies for those populations. So now let's graph it.
Well, on our y axis, it says genotype frequencies. So that's what we just calculated, that p22pq and q2. And we are going from 0 up to 1. And on the x axis, we have allele frequencies and it has 0 and q plotted right next to each other. So p goes from 0 down to 1, and in those same populations, remember because p plus q equals 1, q goes from 1 down to 0.
Alright. So let's start graphing. I'm going to graph, all the p2, then all the 2pqs, then all the q2. For population a, when p equals 0 and q equals 1, we're talking about right here on the graph was p2 equals 0. So dot goes there.
Alright. The next one is when p equals 0.2 and q equals 0.8. So we're talking about right here and there q2 p squared sorry equals 0.04. So real low on the graph there. Now when p equals 0.4 and q equals 0.6, we're talking about right here on the graph and that's going to be p2 equals 0.16, which is gonna be right about there.
Oops, I do it in the wrong spot right about there. Is that not? There we go. Finally, when, for population d, when p and q both equal 0.5,
