Question

Why same restriction endonuclease is employed to cut the cloning vector and donor DNA?

Answer 1

Restriction endonuclease:

1. It is an enzyme that splits DNA into fragments at or close to certain recognition sites within molecules known as restriction sites
2. Restriction enzymes are a class of endonuclease enzymes.
3. Restriction endonuclease mainly protects against foreign genetic material.

The same restriction endonuclease is used to cut the cloning vector and donor DNA because:

1. Restriction endonuclease cuts the DNA molecules at particular sites known as restriction sites, made up of a palindromic sequence.
2. The restriction enzymes cuts at fixed sequences, therefore same restriction enzyme must be used since it forms fragments with complementary sticky ends, therefore facilitating the formation of bonds between them.
3. If specific sequence cuts are not made by the restriction endonucleases, it will become almost impossible to target a particular gene.
4. The random cuts would form different lengths of fragments of DNA, and joining the vector DNA with the required gene will become tough since restriction endonuclease produces blunt ends or sticky ends.