Question

I have recently been told that the components of a PCR mixture need to be added in a specific order: primers, dNTP, and finally polymerase. May I know why this is the case?

Answer 1

Primers are added first in a PCR mixture to bind to the specific target DNA sequence and provide a starting point for DNA synthesis. Then, dNTPs are added as building blocks for DNA synthesis. Finally, polymerase is added to extend the primers and synthesize new DNA strands.

Step-by-step explanation:

In a PCR mixture, the components are added in a specific order for optimal results. Primers are added first because they bind to the specific target DNA sequence and provide a starting point for DNA synthesis. Then, dNTPs (deoxynucleotide triphosphates) are added, which are the building blocks for DNA synthesis. Finally, polymerase is added, which extends the primers and synthesizes new DNA strands.

Adding the components in this order ensures that the primers are available to bind to the target DNA sequence before the polymerase starts synthesizing new strands. If the polymerase was added first, it could start synthesizing DNA before the primers have a chance to bind, leading to nonspecific amplification.