Suppose a DNA Fragment from a Human Gene Has Been

Multiple Choice

Suppose a DNA fragment from a human gene has been cut such that it has sticky ends. A DNA fragment from bacteria with sticky ends complementary to those of the human DNA is added to the mix. What would prevent the complementary ends of the human DNA from rejoining, and thus preventing the formation of a recombinant DNA molecule?

A) DNA ligase
B) Restriction endonuclease EcoRI
C) Reverse transcriptase
D) A cloning vector
E) Nothing