Gene G recombines with gene T at a frequency of 7%, and ...

Question

Gene G recombines with gene T at a frequency of 7%, and gene G recombines with gene R at a frequency of 4%.

Assuming that organisms with any desired genotype are available, propose a genetic cross whose result could be used to determine which of the proposed genetic maps is correct.

Accepted Answer

Welcome back, everyone. Let's look at our next problem. It says the frequency of recombination between genes A and B is 17% and between genes B and C is 5% determine the sequence of the three genes. And our answer choices are choice A. Then here's the genes, ABC choice B, the genes are AC B choice C. The genes are C A B and choice D says both A and B and choice, E says both B and C. So kind of wordy there. So let's look at our information we have knowing that recombination frequency is proportional to the distance between the genes. So our greatest distance, which is usually the way, the good way to start is between A and B And the distance between A and B is reflected by a recombination frequency of 17%. So I've drawn a line between a and B and written 17% above it. Now, we know that the gene, this, this frequency recombination frequency between genes B&C is 5%. So that means we could put gene C in between A and B. So just a little ways away from B, we'll write letter C. So it's in between A and B and we'll say that the distance between C and B is 5% Or, you know, reflected by a recombination frequency of 5%,, Leaving the distance between A and C that is 12%. But that's all the information we're given, we're not given this in recombination frequency between A N C and that means that C could also be, and I wrote everything in blue. Now, I'm gonna write in, in red or other possibility. She could also be on the other side of B With the distance of 5% between B&C making our order ABC. That would put the distance between A and C as 17% plus 5% or 22%. So because we're given no further information, we only have the distance between A and B and the distance between B and C. We don't have any information to go by to see if C is which side of BC is on. So we have two possible orders. So one is AC B and in our answer choices, AC B is choice B. So I'm just going to mark that with a little dot And then our other possibility is to have the order ABC which is answer choice A, the one possibility we can rule out is choice C which is C A B putting A in between B and C because that would mean that the distance between B and C would have to be greater than the distance between B and A. We know both of those and we know that's not the case. So I can eliminate choice C, which also means I can eliminate choice E both B and C, but I know that both A and B are potential orders. And therefore my answer is going to be choice D, both A and B for the sequence of those three genes. See you in the next video.

Gene G recombines with gene T at a frequency of 7%, and gene G recombines with gene R at a frequency of 4%.

Assuming that organisms with any desired genotype are available, propose a genetic cross whose result could be used to determine which of the proposed genetic maps is correct.

Key Concepts

Recombination Frequency

Genetic Mapping

Test Cross

Watch next

Gene G recombines with gene T at a frequency of 7%, and gene G recombines with gene R at a frequency of 4%.Assuming that organisms with any desired genotype are available, propose a genetic cross whose result could be used to determine which of the proposed genetic maps is correct.

Key Concepts

Recombination Frequency

Genetic Mapping

Test Cross

Watch next

Gene G recombines with gene T at a frequency of 7%, and gene G recombines with gene R at a frequency of 4%.

Assuming that organisms with any desired genotype are available, propose a genetic cross whose result could be used to determine which of the proposed genetic maps is correct.