Which of the following satements is not applicable to the replica plate experiment of Lederberg and Lederberg ?

Options

A. Mutations are actually pre-adaptive .
B. Pre-adaptive mutations appear without exposure to new environment .
C. The new environment induces mutations
D. The new environment only selects the pre-adaptive mutations that occurred earlier.

Answer

### Step-by-Step Solution:

1. **Understanding the Experiment**: The replica plate experiment was conducted by Joshua and Esther Lederberg in 1952. It aimed to demonstrate that mutations in bacteria occur before they are exposed to selective pressures, such as antibiotics, rather than as a direct response to those pressures.

2. **Purpose of the Experiment**: The main goal was to provide evidence for Darwin's theory of pre-adaptive mutations. This theory suggests that organisms possess mutations that can provide advantages in future environments even before they encounter those environments.

3. **Experimental Procedure**:
- The researchers cultured bacteria on an original plate.
- They then used a method called "stamping" to transfer the bacteria to a replica plate.
- This involved covering the original plate with a cloth, which would pick up the bacteria, and then pressing that cloth onto a new plate to transfer the bacteria.

4. **Treatment with Antibiotics**: After transferring the bacteria to the replica plate, the researchers treated the bacteria with penicillin (or streptomycin). They observed that some bacterial strains survived while others did not.

5. **Observations and Conclusions**:
- The surviving strains had pre-adaptive mutations that allowed them to resist the antibiotic.
- This demonstrated that the mutations were present before the bacteria were exposed to penicillin, supporting the idea that mutations are pre-adaptive rather than induced by environmental pressures.

6. **Identifying the Incorrect Statement**: The question asks for a statement that is not applicable to the replica plate experiment. The correct answer would be a statement suggesting that new environments induce mutations, as the experiment showed that mutations existed prior to exposure to the antibiotic.

### Final Answer:
The statement that is not applicable to the replica plate experiment of Lederberg and Lederberg is: "The new environment induces mutation."

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