Question

How do you choose which restriction enzymes to use when cloning a gene?

Answer 1

The restriction enzyme is also known as restriction endonuclease or molecular scissor, it is used to cut the DNA at a specific point. The restriction enzyme is isolated from bacteria which is named based on bacteria and its strain.

Complete answer:
The restriction enzyme is also known as restriction endonuclease and the first restriction endonuclease was discovered by Smith in 1968, which was named Hind II and it was isolated from Haemophilus influenzae. For cloning of a gene, the DNA sequence initiates the replication and produces several copies after that the selectable marker of the plasmid is used to distinguish the recombinant and non-recombinant gene. After that, the alien gene is used to insert in the recognition site with the help of restriction enzymes because the occurrence of more than one recognition site will disturb the gene cloning. The restriction enzyme is of two types: one which cuts both the strands of the gene by creating blunt ends and the second which cuts both strands of the gene by creating sticky ends. The selection of restriction enzymes depends on its creating of the sticky end which would be used for insertion and cloning. The restriction enzyme cuts its specific point by choosing the palindromic sequence on its own.

Note:
The defense mechanism of bacteria is also named restriction-modification system by Arber and it is divided into restriction enzyme and methylase. The methylase enzyme adds a methyl group to the palindromic region to modify the bacterial DNA by which the restriction enzyme is unable to harm the bacterial genome.