Various types of restriction enzymes commonly used in rDNA technology are:
1) Type I – These enzymes, such as EcoK, serve both as endonucleases and methylases, playing a dual role.
2) Type II – These enzymes, including EcoRI and BglII, exhibit separate cleaving and methylation activities. They are more stable and extensively employed in rDNA technology. Type II restriction enzymes cut DNA at specific sites within palindromic sequences, with thousands of them recognized.
3) Type III – Enzymes like HpaI and MboII cut DNA at specific non-palindromic sequences.
Role of restriction enzymes:
Restriction enzymes play a crucial role in rDNA technology by either cutting DNA straight across in the region of a palindrome, resulting in blunt ends, or by producing short, single-stranded projections at each end of DNA, creating cohesive or sticky ends, also known as staggered ends.