A DNA sequence is cut by two different methods.The first method yields the following fragments (read 5' to 3'): CGATAC;GTCGTCGCC;GTTATCGCGAC.The second method yields the following fragments (read 5' to 3'): CGACGTCGTCGCC;CGATACGTTATCG.What was the original sequence?
A) CGACGTCGTCGCCCGATACGTTATCG
B) GTCGTCGCCCGATACGTTATCGCGAC
C) CGATACGTTATCGCGACGTCGTCGCC
D) CGATACGTCGTCGCCGTTATCGCGAC
E) CGAUACGUCGUCGCCGUUAUCGCGAC

Question

Quizplus · Accepted Answer

To solve this problem, we need to look for fragments that appear in both methods of cutting DNA. In the first method, we have three fragments: CGATAC, GTCGTCGCC, and GTTATCGCGAC. In the second method, we have two fragments: CGACGTCGTCGCC and CGATACGTTATCG. We notice that CGATAC appears in both methods, and this means that it is part of the original sequence. We also notice that GTCGTCGCC appears only in the first method, and CGACGTCGTCGCC appears only in the second method. This means that these two fragments must be adjacent in the original sequence but are cut differently in the two methods. Therefore, the original sequence must be CGATACGTTATCGCGACGTCGTCGCC, which is choice C.

A DNA Sequence Is Cut by Two Different Methods