1, is another bacteriophage that infects E. coli. A normal infection will result
ID: 205984 • Letter: 1
Question
1, is another bacteriophage that infects E. coli. A normal infection will result in some phages growing lytically which lyses the bacterium and some inserting into the bacterial chromosome and allowing the bacterium to continue growing and dividing (lysogens). As a result, plaques tend to be somewhat turbid due to the lysogenic bacteria. Three different genes (named cl, CIl, and clII) are necessary for lysogenic growth and mutations that eliminate the function of any one of these, result in phages that produce clear plaques (called clear mutants). If you were given 10 different clear mutants, describe how you would determine how many genes are involved in lysogeny (if you didn't know there were three), which mutations are in the same gene, and the relative order and distance between mutations in the same gene and give results if the mutations were present in cI, cll, and cllI as follows (distances are shown above brackets in arbitrary map units that show relative distances). Note that recombination between loci in lambda occurs at a frequency of 1 x 103 per map unit. (5 points) 1.9 3.0 1.2 3.0 1.0 2.4 1.6 #3 #1 #5 -- #9 #6 #7 #4Explanation / Answer
To find this out you need to do a complementation test. You will find out that there are three complementation groups.
The total number of complementation groups determines the total number of genes involved.
To find the distance between mutations present in same genes, you have to perform crosses. Let us take the example of complementation group 1.
Similarly you will calculate the distances and the gene order for the other complementation groups.
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