Question

What is insertion inactivation ?How does it is better over antibiotic resistancegene

Answer 1

A vector has more than one antibiotic resistance gene. The foreign DNA is ligated into a restriction site in one of the antibiotic  resistance genes. This involves insertion of the foreign DNA in the DNA sequence of an enzyme like β-galactosidase, which inactivates the enzyme. This is 'insertional inactivation'.