170. In which one of the following PCR assays only one primer is used for amplification?
1. SSR
2. SCAR
3. ISSR
4. CAPS

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Introduction to PCR Assays

Polymerase Chain Reaction (PCR) is a powerful technique used for amplifying specific DNA sequences. There are different types of PCR assays, each designed for a particular purpose, such as genetic analysis, marker development, or sequencing. Among these assays, some use single primers for amplification, while others require two primers. Let’s explore different PCR assays and focus on identifying the one that uses only one primer for amplification.

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Which PCR Assay Uses Only One Primer for Amplification?

Here are the options:

1. SSR (Simple Sequence Repeat)

• SSR markers, also known as microsatellites, typically use two primers that flank the repeat region of interest in the DNA.

• Incorrect Answer

2. SCAR (Sequence Characterized Amplified Region)

• SCAR is a type of PCR assay used to amplify specific DNA sequences that have been previously identified.

• SCAR assays typically use two primers, like most standard PCR assays.

• Incorrect Answer

3. ISSR (Inter-Simple Sequence Repeat)

• ISSR is a PCR technique that amplifies regions between simple sequence repeats. It uses only one primer that is anchored in the repeat region, typically with a specific sequence of nucleotides.

• This makes ISSR unique, as it only requires one primer for the amplification process.

• Correct Answer

4. CAPS (Cleaved Amplified Polymorphic Sequence)

• CAPS markers are used to detect sequence polymorphisms. Like other PCR-based methods, they use two primers for amplification.

• Incorrect Answer

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What is ISSR PCR?

• ISSR PCR is a technique that amplifies regions of DNA between two simple sequence repeats. The primer used in ISSR is usually designed to bind to a region close to a repeat, amplifying the DNA region between two repeat sequences.

• Single primer usage in ISSR allows for a high degree of polymorphism detection, making it useful in genetic diversity studies, species identification, and marker-assisted selection.

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Correct Answer:

3. ISSR

ISSR (Inter-Simple Sequence Repeat) PCR uses only one primer for amplification, making it the correct answer in this scenario.