A fruit fly population has a gene with two alleles, A1 and A2. Te...

Question

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?
a. 0.7
b. 0.49
c. 0.42
d. 0.21

Accepted Answer

Welcome back in our next problem. It says a plant has to Elise for height, big T. Tall and little T dwarf with frequencies of 0.8 and 0.2 respectively. What will be the frequencies of the three possible Jenna types? When we talk about frequencies of alleles or genotype and population, we recall from our content videos that will be wanting to use the hardy Weinberg equilibrium equations. And so when we think about those, we look at the frequency lower case F. Here of our big T allele we know is called P. The frequency of our little Tyla will will designate as Q. And then if we want to look at the frequencies of the three possible genotype says what we're looking for in our answer. Well, our three possible Jenna types are homos, I guess dominant hetero and homo is recessive. So by by hardy Weinberg, if we want to calculate the frequencies of these prototypes, the frequency of the first is going to be P squared. So that will equal 0.8 squared which will equal 0.64. Now, if we're taking a test and we want to speed things along a good thing to do would be to go over to our answer choices and see can we eliminate anything right away? Just the basis on the basis of our very first calculation without having to go through the rest. So let's look at these choices and sure enough, I see choice A gives a value for big T big T of 0.49. Which we know is incorrect. Choice B gives a value of 0.9. Also incorrect. Choice C. Gives the value 0.64. So that is correct. Choice d. gives a value of 0.04 which also incorrect. So again if we were on a test right away, we'd see that after only doing one calculation. We have eliminated every answer. But see However, for the purposes of being thorough in understanding this question will just go through and double check by doing the remaining calculations. So the frequency of the Hetero is two PQ. So two times 0.8 times 0.2 Which gives us an answer of 0.32. And the frequency of the homesickness recessive is Q squared. So that's .2 squared. And that gives us 0.04. So let's just go back over here looking at these answers and we confirm that these are all correct in choice C. So there's our answer right there. See you in the next video

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