The restriction enzymes BamHI and BclI cut at the points indicated by arrows: If one sample of DNA was cut with BamHI and another with BclI, and these two samples were mixed and treated with DNA ligase, what would occur?
A) No DNAs would be ligated (joined together).
B) Only the BamHI-cut DNA would be ligated.
C) Only the BclI-cut DNA would be ligated.
D) Both BamHI-cut and BclI-cut DNAs would be ligated but only to DNA fragments cut with the same enzyme (for example, BamHI fragments would be ligated only to other BamHI fragments).
E) Both BamHI-cut and BclI-cut DNAs would be ligated with no preference for which fragment is ligated to another.

Question

The restriction enzymes BamHI and BclI cut at the points indicated by arrows:  If one sample of DNA was cut with BamHI and another with BclI, and these two samples were mixed and treated with DNA ligase, what would occur?
A) No DNAs would be ligated (joined together). 
B) Only the BamHI-cut DNA would be ligated. 
C) Only the BclI-cut DNA would be ligated. 
D) Both BamHI-cut and BclI-cut DNAs would be ligated but only to DNA fragments cut with the same enzyme (for example, BamHI fragments would be ligated only to other BamHI fragments). 
E) Both BamHI-cut and BclI-cut DNAs would be ligated with no preference for which fragment is ligated to another.

Quizplus · Accepted Answer

Both BamHI-cut and BclI-cut DNAs would be ligated with no preference for which fragment is ligated to another. This is because DNA ligase catalyzes the formation of phosphodiester bonds between the phosphate group at the 3' end of one DNA fragment and the hydroxyl group at the 5' end of another DNA fragment, regardless of their origin or sequence. Hence, the fragments can be joined regardless of their origin and sequence, resulting in a mixture of DNA fragments.

The Restriction Enzymes BamHI and BclI Cut at the Points