Question

1) Imagine that you had two restriction enzymes and a known segment of linear DNA 160 kb long: Enzyme A cuts at location(s): 20 kb, 45 kb 70 kb and 110 kb. Enzyme B cuts at location(s): 15 kb and 140 kb. Based on this information, first construct a linear map of this DNA showing the positions of these restriction enzyme cut sites. In the space below.draw what the gel would look like given the following lanes: (8 points total) Lane 1: DNA only - untreated Lane 2: DNA treated with enzyme A Lane 3: DNA treated with enzyme B Lane 4: DNA treated with both enzyme A and enzyme B (2 points) (2 points) (2 points) (2 points) Label all bands with fragment length for full credit. DNA only untreated DNA +Enzyme A only DNA +Enzyme Bonly DNA +Enzyme A+B - electrode + electrode

Answer 1

The restriction sites for Enzyme A and Enzyme B are given in the diagram below. Blue arrow indicates Enzyme A cute sites and red arrows indicate Enzyme B cut sites.

Enzyme A cut sites 20kb 45kb 70kb 110kb 160kb 15 kb 140kb Enzyme B cut sites

The possible fragments generated upon treatment of 160kb line DNA with Enzyme A are: 140kb, 115kb, 110kb, 90kb, 70kb, 50kb, 45kb, 40kb, 25kb and 20kb. These different sizes of bands would appear on gel.

The possible fragments generated upon treatment of 160kb line DNA with Enzyme B are: 145kb,140kb, 125kb, 20kb and 15kb. These different sizes of bands would appear on gel.

The possible fragments generated upon treatment of 160kb line DNA with both Enzyme A and Enzyme B are: 145kb, 140kb, 120kb, 115kb, 110kb, 95kb, 90kb, 70kb, 65kb, 55kb, 50kb, 45kb, 40kb, 30kb, 25kb, 20kb, 15kb and 5kb. These different sizes of bands would appear on gel.

(To find out how many bands would generate by digestion with particular enzyme, look for the different possible fragments)

After treatment with given enzyme(s), bands on the gel would look like this:

DNA only - untreated DNA + Enzyme A only DNA + Enzyme Bonly DNA + Enzyme A +B - electrode 160kb 140kb 145kb 140kb 125kb 115kb 110kb 90kb 70kb 145kb 140kb 120kb 115kb 110kb 95kb 90kb 70kb 65kb 55kb 50kb 45kb 40kb 30kb 25kb 20kb 15kb 5kb 50kb 45kb 40kb 25kb 20kb 20kb 15kb + electrode

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