The following table shows data from a cross (ABC x abc) examining three genes (a, b, and c). Calculate the recombination frequency for A and B

Okay, so in this question we're going to be practicing, calculating recombination frequencies again, but this time we're going to be doing it with, 3 genes of interest. So this says the following table shows data from a cross that multiplied, or that made it a homozygous dominant, a homozygous recessive, and was looking at the recombination frequency of 3 genes. And it says calculate the recombination frequency for a and b. So here's our table. So let's walk through how to do this. I'm gonna disappear so you can see the table. So that, the column that we're interested in is this one. Right? Because this is the one looking at the recombination frequency between a and b. So how do you do this? With these genotypes and these offspring numbers, how do we know which one is which ones are recombining between a gene a and gene b? So the first thing we do is we know that our parents had either homozygous dominant for both a and b or homozygous recessive for a and b. So any of these genotypes that look like this, those are going to be parentals or non recombinant. So those are the ones we are not interested in. Any of the ones that are recombined of these, so you have an uppercase a and a lowercase b, or a lowercase a and an uppercase b. These are these recombinant. And that's what we're interested in. This right here is what we're interested in. So we go through the genotypes. The first 2 are usually always the parents. Right? Which we can see, a, b, and c and all lowercase, those exactly match the parent phenotypes. So the next one, all we have to do is look at the a and b. So is that a parental phenotype or is that a recombinant phenotype? Well, lowercase a and uppercase b is going to be a recombinant phenotype. Then the next one, we have an uppercase a, lowercase b. Is that parent or recombinant? That's right here. That's a recombinant phenotype. If we look up here, again, it's the same phenotype. It's also going to be recombinant and we look here, that's also recombinant. Whereas, these 2 down here look like parents, so these are non recombinant for a and b and that's the ones we're not interested in. So the 4 we're interested in are here. And those show recombinant between the a and the b gene which is what we're looking for. So the recombination frequency, if you remember, is number of recombinant over total offspring times 100. So our total offspring number, you can put it in your calculator if you want, but just trust me on this, is going to be 991. So if you add all these together, that's gonna equal 991. So in our recombination frequency formula, the denominator is gonna be 991, not 999. 991. And then, what we're the total number of recombinant, we take by adding this one, so 145 plus 152 plus 43 plus 34. And, that is going to be, those numbers there. So take a second, put it in your calculator if you haven't done it. And the answer to that is going to be 374. 374. So you get 374 by doing 145 +152plus43 plus 34, which are a and b recombinant, and that equals 374. So now our recombination frequency is 374 divided by 991. You multiply that by a 100 to get it to a percent, And so the answer here is 37.74%. So the closest answer, that we have available here is going to be c. So there are combination frequency between a and b is 37 percent, which also means that the distance between a and b on a chromosome is going to be 37 mapping units. So that is, practicing recombination frequency. Let's now move on and do the next step.

The following table shows data from a cross (ABC x abc) examining...

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2. Mendel's Laws of Inheritance3h 37m

3. Extensions to Mendelian Inheritance2h 41m

4. Genetic Mapping and Linkage2h 28m

5. Genetics of Bacteria and Viruses1h 21m

6. Chromosomal Variation1h 48m

7. DNA and Chromosome Structure56m

8. DNA Replication1h 10m

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10. Transcription1h 0m

11. Translation58m

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15. Genomes and Genomics1h 50m

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17. Mutation, Repair, and Recombination1h 6m

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20. Quantitative Genetics1h 26m

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The following table shows data from a cross (ABC x abc) examining three genes (a, b, and c). Calculate the recombination frequency for A and B

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