THE ADVENT OF CRISPR Cas9 – NEW GENERATION OF GENOME EDITING TOOLS (A REVIEW)

The prokaryotes possess clustered repeated interspaced short palindromic repeat system (CRISPR), which forms the basis of acquired immunity of single celled organisms against the viral threats. This system works along with the Cas9 enzyme, basically a restriction endonuclease to cleave the sequences at a targeted site complementary to CRISPR. The Cas9 endonuclease can be programmed and is regulated by small guide RNA (siRNA) sequences of about 20 bases long that cleave the DNA at site-specific regions causing mutations. These small guide RNA can be designed to cleave at particular loci, the guide RNA contains complementary base sequence to that of the DNA of our interest, therefore this property of RNA makes CRISPR more efficient tool as the RNA will bind only to the opposite base pairs none other part of DNA. Presently, various experiments on gene engineering, mutagenesis, gene expression are being conducted on various organisms and it is now believed that CRISPR can be used to treat single faulty gene diseases to turn a gene on or shut off and using animals models to study the genetically inherited diseases of humans. This review article will provide new insight on the advancements and applications of CRISPR Cas9 technology.