Answer:
The correct answer would be restriction enzymes.
Restriction enzymes refer to the class of enzymes which are involved in cleaving the DNA molecule at or near a particular site which is termed as a restriction site.
Gene of interest and bacterial DNA are treated with the same restriction enzyme (mostly restriction endonuclease) which help in producing sticky ends in the gene of interest as well as bacterial DNA.
The digestion with restriction enzyme helps in removing the gene of interest from other human DNA. In addition, it opens the circular bacterial DNA.
Lastly, the sticky ends help in inserting the gene of interest into the bacterial DNA.
