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BotanyNEET 2025Tools of recombinant DNA technology

Biotechnology: Principles and Processes

In the plasmid represented in the figure, an alien piece of DNA is inserted at the EcoRI site. Which of the following strategies will be chosen to select the recombinant colonies?

Question 115 as printed in the NEET 2025 booklet

  1. A.Using an ampicillin- and tetracycline-containing medium plate.
  2. B.Blue-coloured colonies will be selected.
  3. C.White-coloured colonies will be selected.✓
  4. D.Blue-coloured colonies grown on ampicillin plates can be selected.

Solution

The EcoRI site lies within the lacZ gene of the vector. An insert there inactivates galactosidase, so recombinant colonies cannot break down the chromogenic substrate and stay white, while non-recombinants turn blue. Select the white colonies.

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