State the best known contribution of
Alec Jeffery

Explanation

**Step-by-Step Solution:**

1. **Identify the Person:**
- The question asks for the best-known contribution of Alec Jeffreys. It is important to note that he is often referred to as Sir Alec Jeffreys, a British geneticist.

2. **Highlight His Major Discovery:**
- Alec Jeffreys is best known for his discovery of DNA fingerprinting in 1984. This was a significant breakthrough in the field of genetics and forensic science.

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