The restriction enzymes most commonly used in rDNA technology are
1. Type 1 Restriction enzymes
2. Type II Restriction enzymes
3. Type III Restriction enzymes
4. Type IV Restriction enzymes
Type I RE-Cleave randomly far from their recognition sites.
Type II RE- Cleave within or close to their recognition sites
Type III RE – Require two recognition sites in opposite orientation and cleave outsid e the recognition site
Type IV RE- Cleave Methylated/Modified DNA sites.