question_answer

(i) EcoRI is a well - known restriction endonuclease. How is it named so? Give details.

(ii) Why is it essential to have a selectable marker in a cloning vector?

Answer:

(i) EcoRI is derived from Escherichia coli RY13. It is named as follows

· The capital letter E is derived from Escherichia (genus).

· The letters 'co' are derived from coli (species).

· The letter R is derived from RY13 (strain).

· The Roman number I indicates that it was the first enzyme isolated from the bacterium E. Coli RY 13.

(ii) It is essential to have a selectable marker in the cloning vector because it helps in identifying and eliminating non - transformants and selectively permitting the growth of transformants.