Arber, Nathan and ............. isolated the first restriction endonuclease.

Explanation

To answer the question, we need to identify the third scientist who, along with Arber and Nathan, isolated the first restriction endonuclease.

### Step-by-Step Solution:

1. **Identify the Scientists Involved**: The question mentions two scientists, Arber and Nathan. We need to find the third scientist.

2. **Recall the Historical Context**: The first restriction endonuclease was discovered in the early 1970s. This discovery is a significant milestone in molecular biology.

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