Chapter 3 - CRISPR-Cas: Effectors, mechanism, and classification

Abstract

CRISPR-Cas9 named as clustered regularly interspaced short palindromic repeats (CRISPR) having Cas9 protein associated with the whole genetic mechanism, eventually applied in all eukaryotic and prokaryotic organisms of the globe for sustainability. In the current research, bacteria depicted unpredictable diversity and complexity in their genome defense system. The usage of CRISPR-Cas9 increased drastically in human life during the current year. It opened new doors through its latest classifications in 2015, running under genome editing technology along with Cas9 genes. The new classification includes 6 types, 2 classes, 33 subtypes as compared to the 16 subtypes as well as 5 types. Some of these variants are RNA-guided transposition while others are applied to perform various functional characterizations to develop genetic and adoptive immunity practically. However, ancillary CRISPR-linked genes, are mostly used in signal transduction. These research findings assist in clarifying the concept of evolutionary and functional diversity of genome editing mechanisms. By taking into consideration, the new bacterial and archeological genomes, there is a need to introduce new classifications of CRISPR-Cas. Furthermore, the new classification will resolve the complexity of the organism's immunity systems resulting in various recombinant variants, therefore, it is necessary to integrate sequence tools, protein comparison, and refine the genes of the neighborhood.