CRISPR-Cas9
CRISPR-Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats – CRISPR-associated protein 9) is a revolutionary gene-editing technology that uses a guide RNA to direct the Cas9 endonuclease to a specific DNA sequence, where it makes a precise double-strand cut. Originally discovered as a bacterial adaptive immune system, it was adapted for genome editing by Jennifer Doudna and Emmanuelle Charpentier in 2012, earning them the Nobel Prize in Chemistry in 2020. CRISPR-Cas9 enables targeted gene knockout, correction, and insertion across virtually any organism.
Comparison of Gene-Editing Technologies
| Technology | Year | Precision | Ease of Use | Off-target Effects |
|---|---|---|---|---|
| Zinc Finger Nucleases (ZFN) | 1996 | Moderate | Difficult | High |
| TALENs | 2010 | High | Moderate | Moderate |
| CRISPR-Cas9 | 2012 | Very High | Easy | Low–Moderate |
| Base Editing (BE) | 2016 | Very High | Moderate | Very Low |
| Prime Editing | 2019 | Highest | Moderate | Very Low |
Interactive Tools
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Related Terms
PCR (Polymerase Chain Reaction)
PCR is a molecular biology technique used to amplify specific DNA sequences exponentially through repeated cycles of denaturation, annealing, and extension. Developed by Kary Mullis in 1983, it allows scientists to produce millions of copies of a target DNA segment from even minute quantities of template DNA. PCR is foundational to genetic research, diagnostics (including COVID-19 testing), forensic analysis, and cloning applications.
Epigenetics
Epigenetics is the study of heritable changes in gene expression that do not involve alterations to the underlying DNA sequence, but are caused by chemical modifications to DNA or histone proteins. Key mechanisms include DNA methylation, histone acetylation, and non-coding RNA regulation, which collectively control which genes are switched on or off in different cell types and developmental stages. Epigenetic modifications can be influenced by environmental factors such as diet, stress, and toxins, and some modifications can be passed to offspring.
Genomics
Genomics is the branch of molecular biology concerned with the structure, function, evolution, mapping, and editing of the complete set of DNA (genome) of an organism, including all genes and non-coding sequences. Unlike classical genetics, which studies individual genes, genomics takes a large-scale approach using high-throughput sequencing technologies and bioinformatics to analyse entire genomes simultaneously. Genomics drives advances in personalised medicine, drug discovery, evolutionary biology, and agricultural improvement.
CRISPR is an acronym for Clustered Regularly Interspaced Short Palindromic Repeats, first described by Francisco Mojica in 1993. "Cas9" refers to CRISPR-associated protein 9. The term was adapted into a gene-editing tool by Doudna and Charpentier in 2012. "Palindromic" comes from Greek palindromos (running back again).