Using the genomic libraries in Problem 4, you wish to clone the h...

Question

Using the genomic libraries in Problem 4, you wish to clone the human gene encoding myostatin, which is expressed only in muscle cells.

Assuming the human genome is 3x10⁹ and that the average insert size in the genomic libraries is 100 kb, how frequently will a clone representing myostatin be found in the genomic library made from muscle?

Accepted Answer

Welcome back, everybody. Here's our next problem. What is the expected frequency of finding a clone representing the insulin receptor gene in a genomic library made from liver tissue? Given that the size of the gene is approximately 150 kg bases and the human genome comprises 3.2 billion base pairs. Assumptions the genomic library made from liver tissue. OK, contains a total of 100,000 clones. And after screening the library, 20 clones are identified to contain the insulin receptor gene choice. A one in four B, one in 20 C one in 5000 D one in 20,000. So this is an example of a question that actually gives us more information than we need. I am looking for how often I expect to find a clone with the insulin receptor gene in this specific genomic library. So we're looking for the chance of finding a specific clone in a specific genomic library. Normally, when we be looking for the frequency of how likely is it that we'll find a clone? Um be in a genomic library, we'd need to look at the size of the gene and the size of the human genome because we'd be saying in the whole human genome, how likely are we to hit on that gene? However, in our assumptions, we are given that there are 100, clones in the library. So we've got the size of the library and then it says that 20 clones in the library are identified to contain this gene. So we have how many of the clones contain the desired gene. So this turns into a very simple math problem where we just need to divide. We say we have, we know that 20 clones contain the gene. Our library has 100,000 clones. So 20 out of 100,000 clones contain the gene we're looking for. So our frequency of finding a clone with the gene will equal divided by 100,000. So that's quite an equal which if we simplify that fraction will equal one divided by 5000. And if we look at our answer, choices, choice C is one and 5000. So that is our answer. The expected frequency of finding a clone representing the insulin receptor gene and a genomic library made from liver tissue. With the assumptions we were given is choice C one in 5000. See you in the next video.

Watch next