An attached-X female fly, XXY (see the 'Insights and Solutions' b...

Question

An attached-X female fly, XXY (see the 'Insights and Solutions' box), expresses the recessive X-linked white-eye mutation. It is crossed to a male fly that expresses the X-linked recessive miniature-wing mutation. Determine the outcome of this cross in terms of sex, eye color, and wing size of the offspring.

Accepted Answer

Hey, everyone. Let's take a look at this question together, identify a condition that will result in fertile female droil of flies. Is it answer choice? A two sets of autosome and two X chromosomes. Answer choice B, three sets of autosome and two X chromosomes with one Y chromosome. Answer choice C two sets of autosome and three X chromosomes or answer choice D two sets of autosome and one X chromosome with one Y chromosome. Let's work this problem out together to try to figure out which of the following answer choices will result in a fertile female Drosophila fly. So we know that when it comes to the sex of the Drosophila flies, it is determined by that X to a ratio where the X is the X chromosome number in the A refers to the artis number, which means that the ratio of X chromosomes to autosome will determine the sex of the Drosophila offspring. And when we're talking about a fertile female, specifically, a ratio value of one will result in fertile females. So when we calculate the ratio of X chromosomes, two AES, any value that results in one will result in fertile female Drosophila flies. So starting off with answer choice A, we see we have two sets of autosome and two X chromosomes, which means that the X chromosome two AOM ratio is to 2, which equals one. So answer choice A will result in those fertile female Drosophila flies. But let's check answer choices. BC and D to see if there are any other options. Answer choice B says we have three sets of autosome and we have two X chromosomes, which means that our X to a ratio is 2 to 3, which equals 0.66 which does not equal one. So answer choice B is incorrect. Answer choice C says two sets of autosome and three X chromosomes, which means that we have an X to a ratio of 3 to 2, which equals 1.5, which does not equal one since we cannot go over one. So answer choice C is also incorrect. And lastly answer choice D says that we have two sets of autosome N one X chromosome, which means that we have a ratio of 1 to 2 which equals 0.5 and does not equal one. So answer choice D is also incorrect, which means that answer choice A two sets of autosome and two X chromosomes is the only answer choice here, which is a condition that will result in fertile female Drosophila flies. So answer choice A is the correct answer because we know that the sex of the Drosophila flies is determined by that X to a ratio which is the ratio of X chromosomes to autosome. And in order for the offspring to be those fertile females, the ratio value must be one. So looking at our answer choices, we see that answer choice A is the only ratio here in which we are given that ratio value equal to one because we have two sets of AES and two X chromosomes. So the ratio is 2 to 2 which equals one. So answer choice, a two sets of AES and two X chromosomes is the only correct answer choice here. I hope you found this video to be helpful. Thank you and goodbye.

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