Question

5. You have a linear DNA fragment and you wish to generate a restriction map using Mstl and EcoR1. When the framgent is digested with Mst1 and the DNA is run on a gel you observe a 4kb and a 6kb fragment. When the DNA is digested with EcoR1, 1kb, 4kb and 5kb fragments are generated, A double digest using both enzymes produce 1kb, 2kb, 3kb and 4kb fragments. Explain these results and draw a restirction map consistent with these results

Answer 1

L a nd 97214, the 000101 Welcome F ce this ideal P i nlammato al HIV-tubre Mst I digest bkb 4kb msti ELRI ECORE ECORI digest Ikb 5 kb 4kb. 4 kb. 3kb akb Kb Mst 2 and ECORI digest EORI MSHI ECORI

In the above image all three restriction fragments drawn separately.

# Total length of the DNA is 10kb

# MstI cuts at 4kb from the starting point of the DNA. This gives 4kb and 6 kb. So MstI has only one restriction site in this DNA.

# EcoRI cuts at 1kb from the starting point and then 5kb from the first cut. This gives 1kb, 5b and 4kb respectively.

# Now if both enzyme used, as usual 1kb of EcoRI, then followed by MstI gives 3+1 kb then EcoRI gives 2+4 kb. Finally the yield will be 1, 3,2 and 4kb.