Bioinformatics Mastery: Genome Engineering using CRISPR Cas9

Genome engineering or gene editing is a way of making specific changes to the DNA of a cell or organism in a controlled way. It is a type of genetic engineering in which DNA is inserted, deleted, modified, or replaced in the genome of a living organism. During the genome editing process, a type of enzyme called "engineered nuclease" cuts the genome in a specific place.

When this is repaired by the cell, a change or an edit is made at the sequence, leading to a change in characteristics of a cell or an organism. There are 3 generations of nucleases for genome editing: (1) Zing Finger Nucleases (ZFNs), (2) TALENs (Transcription activator-like effector nuclease), (3) CRISPR/Cas9. CRISPR/Cas9 is simpler, faster, cheaper, and more accurate than older genome editing methods and thus, it is most commonly used in the genome engineering process.

CRISPR stands for Cluster Random Interspaced Short Palindromic Repeats. It is the DNA-targeting part of the system which consists of an RNA molecule, or ‘guide' designed to bind to specific DNA bases through complementary base-paring. Cas9 is the CRISPR-associated protein 9 and is the nuclease part that cuts the DNA.

The CRISPR/Cas9 system was initially identified as the RNA-based adaptive immune system in bacteria and archaea. The native CRISPR system confers resistance to viruses by incorporating "short repeats" of the viral DNA into the bacterial genome. CRISPR Cas9 technique can be used to treat many hereditary disorders by modifying the mutated genotypes to a normal phenotype.