Which gene isolated from Bacillus thuringiensis has been known to control the insect population of corn borer?

Options

A. HLA-gene
B. Cry I Ab-gene
C. Cry I Ac-gene
D. Cry II Ab-gene

Answer

**Step-by-Step Solution:**

1. **Identify the Source**: The question asks for a gene isolated from Bacillus thuringiensis (Bt) that controls the insect population of corn borer.

2. **Understand the Function of the Gene**: The gene in question is known for providing resistance to certain pests, particularly the corn borer, by producing a toxin that is harmful to these insects.

3. **Recognize the Specific Gene**: The specific gene from Bacillus thuringiensis that is effective against corn borer is known as the cry 1 AB gene. This gene encodes for a protein that produces an endotoxin, which is toxic to the corn borer larvae.

4. **Differentiate Between Other Genes**: It is important to note that there are other cry genes, such as cry 1 AC and cry 2 AB, which target different pests (e.g., cotton bollworm). The cry 1 AB gene is specifically effective against corn borer.

5. **Conclude the Answer**: Therefore, the gene isolated from Bacillus thuringiensis that controls the insect population of corn borer is the **cry 1 AB gene**.

**Final Answer**: The cry 1 AB gene.

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