The CRISPR/Cas technology is used to edit genomes. It is a system, derived from the acquired immunity of prokaryotes. A modified method based on the fusion of the sgRNA molecule and a Cas endonuclease is used in biotechnology. Point mutations are the result of transitions and transversions. Such changes of nucleotides in the genome can lead to development of diseases. CRISPR/Cas-base editors of single nucleotide bases are being developed to modify individual nucleotides. The base editors are a fusion of deaminase enyzmes or reverse transcriptases to Cas9 proteins (e.g., Cas9 nicase or catalytically inactive Cas9 - dCas9). Base editors enable replacement of individual nucleotides in deamination reactions. Development of base editors will be useful to treat monogenic diseases such as sickle cell anemia, β-thalassemia and amytrophic lateral sclerosis, where single nucleotide mutations are the cause of diseases.
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