In which of the following aspect PCR is not leading over gene cloning ?

Options

A. Efficiency
B. Less user's skill
C. Error probability
D. Less expensive

Answer

To solve the question "In which of the following aspect PCR is not leading over gene cloning?", we need to analyze the differences between PCR (Polymerase Chain Reaction) and gene cloning in various aspects.

### Step-by-Step Solution:

1. **Understanding PCR and Gene Cloning**:
- PCR is a technique used to amplify small segments of DNA, producing millions of copies from a small initial sample.
- Gene cloning involves inserting a gene of interest into a vector (like a plasmid) and then replicating that vector in host cells to produce identical copies of the gene.

2. **Efficiency**:
- PCR is generally more efficient than gene cloning because it can quickly amplify DNA without the need for living cells. Thus, it is not the correct answer.

3. **User Skill Requirement**:
- PCR requires less technical skill compared to gene cloning, which often involves more complex techniques and handling of living organisms. Therefore, this is also not the correct answer.

4. **Error Probability**:
- PCR is known to introduce errors during amplification due to the nature of the enzymes used and the conditions of the reaction. In contrast, gene cloning typically produces exact copies of the gene without errors. This suggests that PCR does not lead over gene cloning in this aspect.

5. **Cost**:
- PCR is generally less expensive than gene cloning, as it does not require the same level of resources or time. Thus, this is not the correct answer.

6. **Conclusion**:
- The aspect in which PCR is not leading over gene cloning is "error probability". Gene cloning produces copies without defects, while PCR can introduce errors.

### Final Answer:
The correct option is **error probability**.