Zoology - Biotechnology - Principles and Processes Question with Solution | TestHub

There are three types of restriction enzymes. Type I has a cleavage site at 1000bp away from the restriction site. Type ii is specific within the recognition site. Type III has a cleavage site 24-26 bp away from recognition sites. Only type II is used in rDNA. Type I has a single enzyme which modifies the DNA at specific recognition sites but restriction activities occur randomly and away from the recognition site. Type III have separate enzymes for restriction activity and methylation and cleave outside the restriction site. Thus only type II are highly useful in rDNA because they have a separate enzyme for restriction which cleaves at the specific site