Question

What is the purpose of Emulsion PCR (ePCR) in Next-Generation Sequencing?

• A. To sequence DNA directly without amplification
• B. To amplify individual DNA fragments in isolated microreactors
• C. To detect proteins in sequencing samples
• D. To separate RNA molecules from DNA

Hint:

ePCR → Amplifies single DNA fragments inside microscopic droplets for NGS sequencing

Answer 1

The Correct Option is B

Concept:
Next-Generation Sequencing (NGS) technologies require millions of copies of DNA fragments to generate detectable sequencing signals. One important amplification technique used in some NGS platforms (such as 454 pyrosequencing and Ion Torrent sequencing) is Emulsion PCR (ePCR).
Step 1:Understanding emulsion formation.
In ePCR, DNA fragments are mixed with beads, primers, and PCR reagents in an oil-water emulsion. This mixture forms millions of tiny droplets.
Step 2:Microreactor concept.
Each droplet acts as an independent microreactor containing:

• A single DNA fragment
• PCR reagents
• A bead coated with primers

Step 3:DNA amplification.
PCR amplification occurs inside each droplet, producing many copies of the same DNA fragment attached to the bead. This process ensures that each bead carries identical DNA sequences.
Step 4:Role in sequencing.
After amplification, these beads are placed onto a sequencing chip where the amplified DNA fragments can be read simultaneously during the sequencing process. Conclusion:
Therefore, the purpose of Emulsion PCR (ePCR) in Next-Generation Sequencing is to amplify individual DNA fragments in isolated microreactors.