CRISPR gene editing method can lead to unwanted mutations
CRISPR-Cas9 gene editing technique, considered one of the most powerful tools of modern medicine, may be riskier than previously thought. Researchers have observed that its use can lead to hundreds of dangerous mutations in the genome.
Gene editing method In CRISPR-Cas9 was to revolutionize medicine. It made it relatively easy and inexpensive to b It is possible to cut, add or modify the individual lne genes in plants and animals. Also in humans. It was the CRISPR-Cas9 technique that was supposed to eliminate genetic defects and bring new gene therapies for the diseases plaguing our civilization. However, this may not happen.
Researchers at Columbia University Medical Center, led by Stephen Tsang, conducted an extensive study of the mouse body, which ry was previously subjected to gene editing in the CRISPR-Cas9 method. They observed unwanted mutations in areas that re were not associated with the edited genes. CRISPR-Cas9 can precisely target specific DNA fragments, but changes can also affect other parts of the genome.
These mutations were likely missed in previous studies because analyses focused on observing area in, which rich edited genes were to be affected. Scientists use an algorithm to search for mutations in computerized. – These predictive algorithms appear to work as intended when the CRISPR-Cas9 technique is performed in a com rk or tissues. However, full genome sequencing has not been used to look for all the effects of the in unanticipated mutations – said Alexander Bassuk of the University of Iowa, who was involved in the research.
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a system used by bacteria to defend themselves against viruses. It’s such a defense mechanism, a repeated sequence of fragments in DNA. It was noticed by Yoshizumi Ishino in the late 1980s. Last century in the genome of the bacterium Escherichia coli. This mechanism contains information about the DNA of the virus and combined with a DNA-cutting enzyme – Cas9 endonuclease provides a defense system against viruses.
The CRISPR-Cas9 method itself works by recognizing foreign DNA through mRNA, kt re responsible for carrying genetic information. The entire CRISPR sequence is then divided into cr tice containing a fragment of viral DNA and the CRISPR sequence. Based on this information, a specific virus transcript is created, which ry is remembered by the com rk and used in the fight against the virus. In the case of infection, the pattern of the attacking virus binds to the Cas9 enzyme and cuts the attacker into pieces completely inactivating it. The excised pieces are then added to the CRISPR sequence, a specific database of threats.
Patterns can be created by humans so we can tamper with genes, substituting or cutting out dangerous fragments. The method is cheaper and more precise than those previously used, but, as it turns out, its use can have the opposite effect.
Researchers from Tsang’s team conducted a full genome analysis of dw ch mice, in which rych excised the gene responsible for blindness. They discovered that the technique successfully improved the gene, kt ry causes blindness in mice, but has also caused more than 1,500 single nucleotide mutations. None of these have been indicated by the commonly used by scientistsc in a computer algorithm used to detect the side effects of the techniques.
– Scientists who ers do not use whole-genome sequencing may miss potentially important mutations. Even changing a single nucleotide can make a huge difference – Stephen Tsang said.
What’s worse, mutations have already made headlines after this method was applied to humans. Last year, Chinese researchers gave patients with an aggressive form of lung cancer altered com immune cells. You can read more about this in the text: gene editing method in CRISPR used in humans.
The discovery of American scientists does not mean that the CRISPR-Cas9 method is not suitable for use. More research is needed to confirm the results obtained by US researchers. More research is also needed on the technique itself and the use of a broader picture of the entire genome. However, there is no denying that the extremely promising method may have serious and long-lasting side effects and its future is in question.