試題詳解

39. A plasmid that encodes resistance to ampicillin and tetracycline is digested with the restriction enzyme Sall, which cuts the plasmid at a single site in the tetracycline-resistance gene. The DNA is then annealed with a Sall digest of human DNA, ligated, and used to transform E. coli cells. What antibiotic would you put in an agar plate to ensure that the cells of a bacterial colony contain the plasmid?
(A) Ampicillin.
(B) Tetracycline.
(C) Ampicillin and tetracycline.
(D) Any antibiotic will do.
(E) The agar plate should not contain any antibiotic.