Question

Regarding Assertion and Reason, choose the correct option.
Assertion[A]: Selection markers give straightforward results as to which cells have been transformed.
Reason[R]: Screening markers need X-gal stain to visualize the result of transformation procedure.

• A. [A] is true and [R] is false.
• B. [A] is false and [R] is true .
• C. Both [A] and [R] are true and [R] is a correct explanation to [A].
• D. Both [A] and [R] are true but [R] is not a correct explanation to [A].

Answer 1

The correct option is D Both [A] and [R] are true but [R] is not a correct explanation to [A].

Selection markers involves the usage of antibiotic resistant gene. The cells that get transformed can successfully thrive in a medium containing antibiotic, while the normal cells will die. Screening marker involves using a gene that can impart color or addition of certain stains. X-Gal is one of the most commonly used stain in case of screening marker. But the latter is not the reason for the former and they exist as independent statements.