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The secret of genetic scissors: How does CRISPR accurately repair DNA?
In the current biotechnology and medical fields, CRISPR technology is rapidly attracting widespread attention. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats, referred to as CRISPR) is hailed as a revolutionary technology in genetic engineering. It is derived from the immune system of bacteria and allows scientists to edit the genome of living cells in a precise manner. This technology not only allows researchers to delete or add specific genes, but also brings unlimited possibilities for future medical treatments and gene therapy, playing a key role in the treatment of many diseases.
The implementation of CRISPR technology relies on a nuclease called Cas9. The enzyme, described as "genetic scissors," cuts at specific locations in DNA, causing changes in the cell's genome. Researchers successfully guided Cas9 to the target DNA sequence by synthesizing guide RNA (gRNA), which allows us to directly change the genome of organisms at the molecular level. This is not only the dawn of genetic sequencing, but may also reshape the entire medical industry.
CRISPR technology is considered a major breakthrough in biotechnology and medical fields. It can edit genomes at low cost and with high efficiency.
Historical background of CRISPR technology
The origins of CRISPR technology can be traced back to 2005, when French researchers first discovered the CRISPR site containing a new Cas gene. As research continued to deepen, in 2012, a team led by Jennifer Doudna and Emmanuelle Charpentier at the University of Georgia discovered that the CRISPR-Cas9 system not only has the ability to edit DNA, but can also edit DNA through RNA. Programming greatly improves the accuracy of editing.
However, the widespread use of this technology is not without controversy. Many bioethical issues arise for its use in human embryos. As a result, despite its potential to treat genetic diseases and some cancers, CRISPR still sparks fierce debate in the scientific community.
CRISPR technology can target multiple DNA sites simultaneously, which gives it more flexibility in gene editing.
How CRISPR operates
The core of the CRISPR-Cas9 system lies in its components: Cas9 nuclease and guide RNA (gRNA). The key to gRNA design is to accurately recognize the target DNA sequence and thereby guide Cas9 to the correct location. When Cas9 cuts DNA, the cell uses its own repair mechanisms to repair it. In this process, there are two main repair pathways: homologous recombination repair (HDR) and non-homologous end joining (NHEJ). HDR is capable of precise gene insertion, while NHEJ is more likely to result in random gene deletions or insertions.
As scientists continue to explore the boundaries of CRISPR technology, more and more Cas9 variants are being developed, which have shown better results in reducing non-target editing activities, making gene editing safer.
The design of guide RNA and its interaction with Cas9 is key to the accuracy and efficiency of CRISPR systems.
Future applications of CRISPR
As CRISPR technology continues to develop, its potential applications are also expanding. The latest drug, Casgevy, has been approved in the UK and US. This breakthrough therapy is designed to treat sickle cell disease and beta thalassemia. The success of these treatments demonstrates not only the potential of CRISPR but also the changes it can bring.
In addition, CRISPR technology is also used in agricultural production to develop plants with more disease resistance and production efficiency, and even lays the foundation for the establishment of gene-edited foods. However, the ethical and safety issues caused by this still need to be solved urgently. .
CRISPR was selected as Breakthrough of the Year by AAAS in 2015. The potential of this technology heralds huge changes in medicine and agriculture in the future.
In short, the development of CRISPR technology has undoubtedly brought a new perspective to scientific research and application. What opportunities and challenges will humans face in genome manipulation in the future?
