RNAi is a technique that silences genes by targeting them and degrading their mRNA. How can this technique be used in scientific laboratories?

A. RNAi has been used in laboratories to make bacteria more susceptible to antibiotics, but has limited application in eukaryotic cells.

B. RNAi is a powerful tool for degrading mRNA, but because it doesn't degrade other types of RNA, its use is limited.

C. RNAi is observed in nature, but it can't be used in laboratories.

D. RNAi allows scientists to turn off one gene specifically to study its effect.

The Answer is option D

(D). RNAi allows scientists to turn off one gene specifically to study its effect.

Explanation:

RNAi (RNA interference) can be defined as a process, which involves inhibition of gene expression by degrading the targeted mRNA molecules. This technique is widely used in laboratories to study the functions of different genes by targeting them.

For this, a dsRNA molecule is formed having a sequence complementary to target gene and introduced into the cell or organism. This RNA is recognized as exogenous RNA and triggers activation of RNAi pathway.

RNAi pathway leads to a significant decrease in expression of a target gene. Hence, physiological role of the targeted gene product can be check by studying the effect of decrease in its expression.

Thus, the correct answer is option (D).