Question

Restriction enzymes that are used in the construction of recombinant DNA are endonucleases which cut the DNA at 'specific-recognition sequence'. What would be the disadvantage if they do not cut the DNA at specific-recognition sequence?

Answer 1

The restriction endonucleases cleave the DNA molecules at the specific sites called the restriction sites, that are made of palindromic sequences. If the sequence-specific cuts are not made by the restriction endonucleases, it would become impossible to target the specific gene. The random cuts would result in variable lengths of DNA fragments and the joining of the target gene with vector DNA would have become cumbersome as restriction endonuclease create either the sticky ends or the blunt ends. In both the cases, it is easy to monitor the ligation process. In other words, the r-DNA technology would not have gained the momentum.