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Biology · PYQ NEET UG 2025
हिन्दीThe blue and white selectable markers have been developed which differentiate recombinant colonies from non-recombinant colonies on the basis of their ability to produce colour in the presence of a chromogenic substrate. Given below are two statements about this method: Statement I : The blue coloured colonies have DNA insert in the plasmid and they are identified as recombinant colonies. Statement II : The colonies without blue colour have DNA insert in the plasmid and are identified as recombinant colonies. In the light of the above statements, choose the most appropriate answer from the options given below :
Correct answer · Option 4
Statement I is incorrect but Statement II is correct
Explanation
In insertional inactivation (blue-white selection), presence of a DNA insert inactivates the enzyme beta-galactosidase, so recombinant colonies do not produce blue color (remain white), whereas non-recombinants produce blue color. Hence Statement I is incorrect and Statement II is correct.
