NEETZoologyBiotechnology - Principles and Processes
Given below are two statements: Statement I: In the cloning vector pBR322, insertion of an alien DNA at the SalI site causes insertional inactivation of the tetracycline resistance gene. Statement II: The recombinant transformants produced by this insertion can be selected from non-recombinants by plating them directly on a tetracycline-containing medium. In the light of the above statements, choose the correct answe
Options
- ABoth Statement I and Statement II are correct
- BBoth Statement I and Statement II are incorrect
- CStatement I is incorrect but Statement II is correct
- DStatement I is correct but Statement II is incorrect
Correct answer
D. Statement I is correct but Statement II is incorrect
Step-by-step solution
Statement I is correct. The restriction site for the enzyme SalI is located within the tetracycline resistance gene ( tet^ R ) of pBR322. Insertion of a foreign DNA at this site interrupts the gene, leading to insertional inactivation of tetracycline resistance. Statement II is incorrect. Because the recombinant transformants have lost their tetracycline resistance, they will fail to grow and will die if plated directly on a tetracycline-containing medium. To select them, the transformants must first be plated on a