Mark an incorrect statement :

Options

A. In microinjection technique of gene transfer only one cell can be injected at a time
B. PCR can detect a mutation able to cause a particular disease
C. In denaturation step of PCR the target DNA is heated to `42^(@)`C to `46^(@)` C only
D. The use of restriction enzymes is proceeded by use of chitinases, pectinases, lysozyme etc.

Answer

To determine the incorrect statement from the given options, we will analyze each statement one by one.

### Step 1: Analyze the First Statement
**Statement:** In microinjection technique of gene transfer, only one cell can be injected at a time.

- **Explanation:** The microinjection technique involves using a fine needle to inject recombinant DNA directly into the nucleus of a single animal cell. This method is indeed limited to one cell at a time.
- **Conclusion:** This statement is **correct**.

### Step 2: Analyze the Second Statement
**Statement:** PCR can detect a mutation able to cause a particular disease.

- **Explanation:** PCR (Polymerase Chain Reaction) is a technique used to amplify DNA, allowing for the detection of specific mutations associated with diseases. This capability makes it a powerful tool in genetic diagnostics.
- **Conclusion:** This statement is **correct**.

### Step 3: Analyze the Third Statement
**Statement:** The first step of PCR involves denaturation at a temperature of 42 to 46 degrees Celsius.

- **Explanation:** The first step of PCR, denaturation, requires heating the DNA to approximately 90 degrees Celsius to separate the strands. The temperature range given (42 to 46 degrees Celsius) is incorrect for this step.
- **Conclusion:** This statement is **incorrect**.

### Step 4: Analyze the Fourth Statement
**Statement:** The use of restriction enzyme is preceded by the use of chitinase, pectinase, and lysozyme.

- **Explanation:** This statement describes the process of preparing genetic material for restriction enzyme digestion. Chitinase, pectinase, and lysozyme are indeed used to break down cell walls before restriction enzymes can act on the DNA.
- **Conclusion:** This statement is **correct**.

### Final Conclusion
The incorrect statement among the options provided is the **third statement** regarding the temperature for denaturation in PCR.

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