I am currently in a genetics college course and we received an extra credit restriction mapping problem that no one seems to really understand how to do, and unfortunately the teacher hasn't been much help. If anyone could explain how to do it, I would greatly appreciate it!!

 

Problem:

A piece of DNA 5,000 base pairs long is digested w/ restriction enzymes A and B, singly and together. The DNA fragments produced are separated by DNA electrophoresis and their sizes are calculated with the following results (in base pairs):

Digestion with---

A = 2,100, 1,400, 1,000, and 500

B=2,500, 1,300, and 1,200

A&B=1,900, 1,000, 800, 600, 500, 200

Each A fragment is extracted from the gel and digested with enzyme B and each B fragment is extracted and digested with enzyme A. The sizes of the resulting DNA fragment are determined by gel electrophoresis with the following results:

Fragment A digested with enzyme B

-2,100-->1,900 & 200

-1,400-->800 & 600

-1,000-->1,000

-500-->500

Fragement B digested with enzyme A

-2,100-->1,900 & 600

-1,300-->800 &500

-1,200-->1,000 & 200

Construct a restriction map of the 5,000 bp DNA fragment.

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I forgot to say that this problem is due tomorrow. So any help would be greatly appreciated!!

Unfortunately we do not provide direct answers to question. However, this is basically a simple puzzle in which you have to reconstruct the whole fragment by knowing that each of the provided pieces will be flanked by either restriction site.

Thank you,

 

I know that the answer is not provided, but I am looking for some type of explanation. I know the basic process, but like I said, no one can seem to figure it out in my class.