The letter 'R' in EcoRl is derived from

Options

A. the name of genus
B. the name of strain
C. the name of species
D. the term 'restriction'

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the origin of the letter 'R' in the restriction enzyme EcoRI.

2. **Breaking Down the Name EcoRI**: The name EcoRI can be dissected into parts:
- "Eco" refers to the genus of the bacterium from which the enzyme is derived, which is *Escherichia*.
- "R" refers to a specific strain of the bacterium.
- "I" indicates that it is the first enzyme isolated from that strain.

3. **Identifying the Components**:
- The "E" in EcoRI stands for the genus *Escherichia*.
- The "co" comes from the species *coli*.
- The "R" specifically comes from the strain RY13, which is a particular strain of *E. coli*.

4. **Conclusion**: Therefore, the letter 'R' in EcoRI is derived from the name of the strain RY13.

5. **Final Answer**: The correct answer is that the letter 'R' in EcoRI is derived from the name of the strain.

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