which endonuclease is mosty used among type 1,2,3?

Answer 1

There are three types of restriction endonucleases (Types I, II and III). They are grouped according to their mechanism of action.

Type II REs, more commonly known as restriction enzymes, are the most researched and are used widely in DNA manipulation and analysis. They recognise DNA sequences from 4-16 bp long, depending on the enzyme, and cut between specific bases within this sequence.More than 2,500 type II restriction enzymes have been identified from a variety of bacterial species.