Suppose you want to develop a population of Drosophila that would rapidly learn to avoid certain substances the flies could detect by smell. Based on the heritability estimate you obtained in Problem 16, do you think it would be worth doing this by artificial selection? Why or why not?

Video transcript

Hi everyone. Let's look at our next question. It says in a herd of dairy cows. The fanatic variance for muscle growth and fertility is and 26 respectively. And the additive variance for muscle growth and fertility is 8.2 and 5.2 respectively. Which of the following traits will respond best to selection by a farmer. So we're given the fanatic variants that's present in the entire population of the dairy cows and then the fanatic variants due to additive genetic factors. And when we know those two things. So we've got fanatic variants which would call the P. And then we've got additive variants which we call V. A. We can calculate the heritability in a narrow sense of a particular trait and we can use that with the equation H squared or the heritability equals V. A. Again the peanut variance in population due to additive genetic factors divided by the variance variance in the entire population. This makes sense because we want to look at to what degree does fanatic variants in the population depend on genetic factors. Because if the final question here is which would respond best selection by a farmer. You'd want to look to look for the trait that is most determined by genetic factors. So let's plug in our numbers here, H where it equals and we have our V. A. Is equal to 8.2. Okay, we better specify. This is for the first of these which is muscle growth, muscle growth Which is the first set of numbers listed eight squared is equal to 8.2 here divided by which is the values for additive variants and fanatic variants for muscle growth and the answer we get here. When we do that math Is 0.164. So that's our h wear value for muscle growth. The heritability of muscle growth. So let's look at fertility Their h. Where it is going to be 5.2 which is our v. A. value divided by 26. So we do that calculation And we get 0.2. So now again the greater the heritability, the more it will respond to selection since more of the variance is due to genetic factors. So we want to look for our greater H squared value will be responding best to selection. So when we do that we notice that fertility has an H squared value of 0.2 which is greater than 0.164. So therefore choice B fertility is going to respond best to selection. So let's just look at our other answer choices here choices muscle growth. Obviously we calculated that was not the right answer. Choice C. Both will respond equally. We got two different values that's not correct. And finally choice D insufficient data. Well we had enough we were able to calculate our values and compare them so that's not our correct answer either. So again, when we have this herd of dairy cows. We were given the phenotype variance and additive variance which the following traits will respond best to selection by a farmer. We used that heritability equation picked the one with a higher H. Word value and got the answer of choice be fertility as responding best to selection by a farmer. See you in the next video.