Question

If alien DNA is introduced using Sal I in pBR322 then transformant will grow on

• A. ampicillin
• B. tetracycline
• C. both $\left(a\right)$ and $\left(b\right)$
• D. none of these

Answer 1

Answer: (A)

Sal I restriction site is present in the tetracyclin resistant gene. If foreign DNA is inserted in the Sal I site then the transformant will lose tetracycline-resistant nature due to the insertional inactivation of the tetracycline gene with the insertion of the foreign DNA. The ampicillin-resistant gene will be active and hence, the transformants will grow of ampicillin containing media.