Which of the following is not a cloning vector ?
1) Cosmid
2) pBR 322
3) Sall
4) Phagemid

Options

A. 1) Cosmid
B. 2) pBR 322
C. 3) Sall
D. 4) Phagemid

Explanation

To determine which of the following is not a cloning vector, we can analyze each option provided:

1. **Cosmid**: This is a type of hybrid plasmid that contains a cos site from bacteriophage lambda. Cosmids are used as cloning vectors because they can carry larger fragments of DNA than standard plasmids. Therefore, Cosmid is a cloning vector.

2. **pBR322**: This is one of the first plasmids to be used as a cloning vector. It contains genes for antibiotic resistance and allows for the insertion of foreign DNA. Hence, pBR322 is also a cloning vector.

3. **Sall**: This is a restriction endonuclease, which means it is an enzyme that cuts DNA at specific sequences. It is not a vector but rather a tool used in molecular biology for manipulating DNA. Therefore, Sall is not a cloning vector.

4. **Phagemid**: This is a type of vector that combines features of both plasmids and bacteriophages. Phagemids can be used for cloning and are considered cloning vectors.

After analyzing all the options, we conclude that the only option that is not a cloning vector is:

**Answer: 3) Sall**