The earliest record of point mutation is :-

Options

A. Short legged sheep by Seth Wright
B. White eyed male Drosophila by Morgan
C. Autotropic mutants of Neurospora by Beadle and Tatum
D. Matants of Escherichia coil discovered by Joshua Lederberg

Answer

To solve the question regarding the earliest record of point mutation, we will analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding Point Mutation**:
- Point mutations are changes in a single nucleotide base pair in the DNA sequence. They can lead to various genetic variations and are fundamental in the study of genetics.

2. **Reviewing the Options**:
- **Option 1**: Short-legged sheep (Ancon breed) observed in 1791.
- **Option 2**: White-eyed male Drosophila by Morgan in 1910.
- **Option 3**: Autotropic mutant of Neurospora by Beadle and Tatum in 1941.
- **Option 4**: Mutant of Escherichia coli discovered by Joshua Lederberg in 1952.

3. **Analyzing Each Option**:
- **Option 1**: The short-legged sheep (Ancon breed) was noted for its beneficial trait of being unable to cross fences, which was a mutation observed in 1791.
- **Option 2**: Morgan's work with the white-eyed Drosophila in 1910 is significant in genetics but is not the earliest record.
- **Option 3**: Beadle and Tatum's work in 1941 involved exposing Neurospora spores to X-rays, leading to mutations, but again, this is later than 1791.
- **Option 4**: Lederberg's research in 1952 on E. coli focused on antibiotic resistance mutations, which is also after the first option.

4. **Conclusion**:
- The earliest record of a point mutation is the observation of the short-legged sheep (Ancon breed) in 1791. Therefore, the correct answer is **Option 1**.

### Final Answer:
The earliest record of point mutation is the short-legged sheep (Ancon breed) observed in 1791.

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