試題詳解

50. Multi-cloning sites ("poly-linkers") in most commercially available plasmids offer all the following advantages over the earlier plasmids used in genetic recombination       except      :
(A) They can be used with a wide variety of restriction enzymes.
(B) They assure that only the desired DNA will be inserted into the plasmid.
(C) They enable easy control of the direction of insertion of the gene of interest.
(D) They are usually adjacent to any necessary promoters for gene expression.
(E) All of these are advantages.