question_answer

This is figure of plasmid pBr322. The gene conferring resistance of ampicillin (ApR) can be interrupted by insertion of a DNA fragment into the Psti site, and the gene conferring resistance to tetracycline (TcR) can be interrupted by insertion of a DNA fragment into the BamHI site. Replication is controlled by the ColEl origin. Use of the TcR and ApR genes allows for easy screening for recombinant carrying inserts of foreign DNA. For locating Eco RI, TcR and ApR genes on it. Identify what is represented by A, B and C.

A) A-TcR, B-ApR and C-EcoRI

B) A-EcoRI, B-ApR and C-TcR

C) A-TcR, EcoRI and C-ApR

D) A-ApR, B-TcR and C-EcoRI