A mixed infection of two bacteriophage strains was performed. Infection of bacteriophage strain 1 causes the bacteria to be red and large, while infection of bacteriophage strain 2 causes the bacteria colony to be black and small. The following results were obtained. Using this data, determine the distance between the color and size genes.

Okay. So, in this question, a mixed infection was performed with 2 different bacterial phage strains, so 2 different viral strains, and it says strain number 1 causes the bacteria to be red and large, which means that if you infect a plate of bacteria with this strain number 1, those colonies that get infected will become red and large. If you infect with strain number 2, what you're going to get is you're going to get bacterial colonies that are black and small. And the reason that the bacterial colonies become this way is because of genes found in the virus genome. They make the bacteria either red and large or black and small depending on the strain. And so we would consider these with a mixed infection, we would consider these parentals. Right? So these are our parental phenotypes, because this is what the normal strain 1 or strain 2 look like. But because we're doing a mixed infection, there's a potential for recombination between the two viral genomes. So our recombinant number 1 and recombinant number 2 would look like what? They look like mixtures of the parents. So the first one would look red and small, and the second one would look black and large. And these are the 2 recombinants that could be formed from, this, from these mixed infections. So we have our parentals and we have our recombinants. So let's read the following question. It says, the results were obtained. Here here are the results. Using this data, determine the distance between the color and size gene. So here's, obviously, the color gene, and here's, obviously, the size gene. And so, we're looking at the distance, and so that means that we need to map the distance of these two genes. And so, how do we map genes? What's that calculation we use to map genes? We use the recombination frequency. And remember, the RF is going to be equal the total number of, recomps over total number of offspring. And, in this case, because we're looking at bacteria, we're looking at colonies. So let me disappear, we can calculate this. So we have our red and large, so this is a parental. We have our black and small, this is a parental. We have our red and small, this is a and we have our black and large, which is a recombinant. So to calculate the recombination frequency, what we have to do is add the total number of recombinants over the total number of colonies. So when we do these additions, what do we get? We get 50 and over, what's 300 plus 280, that's gonna be 580 plus 50 more. So that's going to be, 6 630. So I don't know that in my head. I'm not going to do it. But if we divide 50 by 630, we get 0.08. And remember, to do the combination frequency, we have to times it by a 100. So 0.08 times 100 is going to equal what? It's going to equal 7.94%. And so to using the, or it's so I did this in a calculator that only goes out to 2 decimal points, it's going to equal 8%, essentially, but depending on how many cal what calculator you use and how many decimal points it goes out, it'll be 8% or 7.94%, depending on decimal points. Either way, it rounds up to 8 and, what it's close to, we look at our answers here, is going to be c. Remember, math units, which is m Mu here, is going to equal the recombination frequency percentage. So 8% or 7.94 depending on what type of calculator, how many decimal points you use, but essentially they're obviously, pretty equal. So, in this case, the color and the size genes, so if I were to draw out, let me scroll down just a little bit more, if I were to draw a chromosome here and say the color gene is here and the size gene is here, then they would be 7.9 Map Units apart. So, with that information, let's move on.

A mixed infection of two bacteriophage strains was performed. Inf...

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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

9. Mitosis and Meiosis1h 34m

10. Transcription1h 0m

11. Translation58m

12. Gene Regulation in Prokaryotes1h 19m

13. Gene Regulation in Eukaryotes44m

14. Genetic Control of Development44m

15. Genomes and Genomics1h 50m

16. Transposable Elements47m

17. Mutation, Repair, and Recombination1h 6m

18. Molecular Genetic Tools19m

19. Cancer Genetics29m

20. Quantitative Genetics1h 26m

21. Population Genetics50m

22. Evolutionary Genetics29m

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