Identify the incorrect match.

Options

A. `i` gene of lac - operon - Constitutive gene
B. `a` gene of lac - operon - Luxury gene
C. Single sequence repeat - Minisatellite
D. Negative control of lac-operon - Repressor

Answer

To identify the incorrect match, we need to analyze each option provided in the question. Here’s a step-by-step breakdown of the analysis:

### Step 1: Analyze the I gene of lac operon
- The I gene of the lac operon is known to be a constitutive gene.
- It codes for the repressor protein that inhibits the expression of the lac operon when lactose is not present.
- **Conclusion**: This match is correct.

### Step 2: Analyze the A gene of lac operon
- The A gene of the lac operon codes for the enzyme transacetylase.
- Transacetylase is involved in the metabolism of lactose, assisting the function of beta-galactosidase.
- **Conclusion**: This match is correct.

### Step 3: Analyze single-sequence repeat with mini-satellite
- A single-sequence repeat (SSR) is more commonly referred to as a microsatellite.
- Mini-satellites are different from microsatellites; they consist of longer repeating units.
- **Conclusion**: This match is incorrect.

### Step 4: Analyze negative control of lac operon with repressor
- The negative control of the lac operon is indeed mediated by the lac repressor protein.
- The repressor binds to the operator region of the lac operon to inhibit transcription when lactose is absent.
- **Conclusion**: This match is correct.

### Final Conclusion
The incorrect match is the one that pairs single-sequence repeat with mini-satellite. Therefore, the answer is option 3.