Suppose you have three Hfr strains of E. coli: A, B, and C. All are derived from a wild type prototrophic, strS, F+ stra
Posted: Wed Jul 06, 2022 10:21 am
Suppose you have three Hfr strains of E. coli: A, B, andC. All are derived from a wild type prototrophic, strS, F+ strainof E. coli. In separate experiments, you mate each strain to an F-recipient strain. Using an interrupted mating experiment, youdetermine the earliest time after mating that each of the markerscan be detected in the F- recipient strain, as shown below. Thedata in the table are minutes. Maximal time of mating was 30minutes.
Gly+
Lys+
Nic+
Phe+
Tyr+
Ura+
HfrA x F-
6
0
9
2
3
5
HfrB x F-
13
2
0
9
10
12
HfrC x F-
15
2
12
19
18
16
Note: 0 means there was no transfer of that gene duringthe entire 30 min mating experiment.
Below is a circle that represents the bacterial genome.On this circle, draw the best map you can based on the availabledata. Mark the relative location of each of the 6 genes, theposition and orientation of all 3 integrated Hfr plasmids, and thedistance in minutes between each around thecircle.
Start with figuring out the order of the genes. Thenfigure out where the Hfr plasmids are situated between the genes.Then put them on the map and mark the distances between. See figure16-4 in your textbook for an idea for how to mark the genes and Hfrorientations. The difference is that the book has separate maps foreach Hfr strain, but here you will mark all Hfr positions andorientations on the same map.
Gly+
Lys+
Nic+
Phe+
Tyr+
Ura+
HfrA x F-
6
0
9
2
3
5
HfrB x F-
13
2
0
9
10
12
HfrC x F-
15
2
12
19
18
16
Note: 0 means there was no transfer of that gene duringthe entire 30 min mating experiment.
Below is a circle that represents the bacterial genome.On this circle, draw the best map you can based on the availabledata. Mark the relative location of each of the 6 genes, theposition and orientation of all 3 integrated Hfr plasmids, and thedistance in minutes between each around thecircle.
Start with figuring out the order of the genes. Thenfigure out where the Hfr plasmids are situated between the genes.Then put them on the map and mark the distances between. See figure16-4 in your textbook for an idea for how to mark the genes and Hfrorientations. The difference is that the book has separate maps foreach Hfr strain, but here you will mark all Hfr positions andorientations on the same map.