Seven deletion mutations (1 to 7 in the table below) are tested for their ability to form wild-type recombinants with five point mutations (a to e). The symbol "+" indicates that wild-type recombination occurs, and "-" indicates that wild types are not formed. Use the data to construct a genetic map of the order of point mutations, and indicate the segment deleted by each deletion mutation.

Question

Seven deletion mutations (1 to 7 in the table below) are tested for their ability to form wild-type recombinants with five point mutations (a to e). The symbol "+" indicates that wild-type recombination occurs, and "-" indicates that wild types are not formed. Use the data to construct a genetic map of the order of point mutations, and indicate the segment deleted by each deletion mutation.

Table showing deletion mutations and their effects on point mutations in bacteriophage genetics.

Accepted Answer

Hello everyone and welcome to today's video. So four point mutations are tested in pair crosses with five delicious mutations for their ability to yield wall type recombinant. And the results for the same are provided below. And so we are given a table that is crossing the point mutations and the deletion mutations for each of these recants. Now we need to determine the relative order of the point mutations. Now as answer choice A, we have A then B, then C, then D as answer choice B, we have B then A, then D, then C as answer choice C, we have C, then D, then A then B and as answer choice D, we have D, then B, then C then a. Well, remember that we can use these cross table that we are given that is crossing the appoint mutations and the deletion mutations. In order to create this order. For example, the specific mutations that are found, the specific deletion mutations are going to be represented by these negative sign. So if we can order these per strain, we're going to be able to determine the overall order of each mutation. Now, for example, for strain number one, we have that there are deletion mutations in B and see. And so we're going to be writing that down next to the table. Then we have strain two and strain two is going to have these mutations in A and see which we can reorder in whatever order we want as long as they are together. So we're going to obtain something like this. Then we have three and three is going to have these mutations in B and D, which is going to look something like this. And then we have four and four is going to have mutations in B in C and in A and they're all keeping the same vertical order. As we can see. Finally, we have five and five is going to have these mutations in the in B and see. So here we have been able to determine the overall order by simply matching these different point mutations and deletion mutations. And we can see that the overall order is going to be D BC and then A at the end. So we're going to be writing that down. So the correct answer choice here is D, then B, then C, then A or answer choice. D, I really hope this really helped you and I hope to see you on the next one.

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Key Concepts

Genetic Mapping

Recombination

Deletion Mutations