In vitro repeated replication of selected DNA components is

Options

A. Gene amplification
B. Gene replication
C. Gene synthesis
D. Pleiotropy.

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question asks about the term used for the in vitro repeated replication of selected DNA components. "In vitro" means that the process is carried out in a controlled laboratory environment, outside of a living organism.

2. **Identifying the Process**: The process involves the replication of a specific segment of DNA, often referred to as the gene of interest. This is typically done to create multiple copies of that gene for various applications, such as gene cloning.

3. **Correct Terminology**: The term that describes the in vitro repeated replication of selected DNA components is "gene amplification." This is a crucial process in molecular biology, particularly in recombinant DNA technology.

4. **Technique Used**: The primary technique used for gene amplification is the Polymerase Chain Reaction (PCR). PCR allows for the exponential amplification of a specific DNA segment.

5. **Steps of PCR**:
- **Denaturation**: The double-stranded DNA is heated to approximately 94-95°C, causing the strands to separate.
- **Annealing**: Primers are attached to the single-stranded DNA at specific locations. These primers are short sequences of nucleotides that provide a starting point for DNA synthesis.
- **Extension (Polymerization)**: A thermostable enzyme called Taq polymerase synthesizes new DNA strands by adding nucleotides to the primers, effectively creating copies of the target DNA.

6. **Conclusion**: Therefore, the answer to the question is that the in vitro repeated replication of selected DNA components is called "gene amplification," and the technique used for this process is PCR.

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