The new genomic editing system (CRISPR)

Over the past decades, progression in genetic element manipulation, and consequently, the treatment of diseases has been remarkable. It is worth noting that these genetic manipulations perform at different levels, including DNA and RNA. The earlier genomic editing techniques, including MN, ZFN , TALEN , performing their functions by creating double-stranded breaks (DSBs), and after breakage, the cell tries to repair the breakage through two systems, homologous recombination and non-homologous end joining. CRISPR/Cas technology has been discovered recently, and has become the most widely used genome-editing tool, mainly due to its capabilities and those added to this through the genetic engineering. In this study, we aimed to introduce a variety of CRISPR classes in the elementary parts, and then the modified CRISPR systems developed to increase the efficiency and specificity of the system and provide acceptable results will be introduced. In this study, for three months in the fall and winter, Pubmed and Web of science sites searched for keywords such as CRISPR, Types of CRISPR, gRNA, Cas9, and CRISPR-Cas9 nickase that eventually resulted in about four hundred Sixty-one articles, and some of these articles after closer study, reviewed in this article. Genetic engineering techniques have successfully transformed this system into the most efficient genome editing tool in recent years. Researchers are working on a system to treat various diseases by resolving problems such as high specificity, cutting off non-target sites, how to move to a cell, and setting up a proper repair system.