Which of the following information is critical to the success of $\mathrm{PCR}$ ($Polymerase$ $Chain$ $Reaction$)?

• A. The color of the $\mathrm{DNA}$ sample
• B. The brand of the $\mathrm{PCR}$ machine
• C. The sequence of the target $\mathrm{DNA}$
• D. The temperature of the laboratory

Answer: (C)

Verified step by step guidance

1. Understand the purpose of Polymerase Chain Reaction (PCR): PCR is a technique used to amplify a specific segment of DNA, making millions of copies of a particular DNA sequence.
2. Identify the critical components required for PCR: These include the DNA template containing the target sequence, primers that are complementary to the target sequence, DNA polymerase enzyme, nucleotides, and a buffer solution.
3. Recognize the importance of the DNA sequence: The sequence of the target DNA is crucial because it determines the design of the primers. Primers must be complementary to the sequences flanking the target region to initiate DNA synthesis.
4. Consider the role of temperature in PCR: PCR involves repeated cycles of heating and cooling to denature the DNA, anneal the primers, and extend the DNA strands. The precise temperature settings are critical for the success of the reaction.
5. Evaluate the non-critical factors: The color of the DNA sample and the brand of the PCR machine do not affect the success of PCR. The key is the accurate design of primers based on the target DNA sequence and the correct thermal cycling conditions.