■ It is a type of genetic engineering in which DNA is inserted, deleted or replaced in the genome of a living organism using engineered nucleases, or “molecular scissors.”
■ These nucleases create site-specific double-strand breaks (DSBs) at desired locations in the genome.
■ The induced double-strand breaks are repaired through nonhomologous end-joining (NHEJ) or homologous recombination (HR), resulting in targeted mutations (‘edits’).
■ Four families of engineered nucleases being used:
zinc finger nucleases (ZFNs)
C) transcription activator-like effector-based nucleases (TALEN), and
D) #Clustered_regularly_interspaced_short_palindromic_repeats (CRISPR)-Cas system.