In one fell swoop

A group of researchers from the University of California at Los Angeles has modified the CRISPR genome editing technology, making it more efficient and faster.

Researchers are able to make the same changes in a large number of cells, but it was impossible to make thousands of different changes at the same time (in different parts of DNA).

Now, in the time it takes to edit and analyze several mutations, tens of thousands of changes can be made. The acceleration of the process will not affect the quality and accuracy of editing.

The CRISPR system consists of two components. These are the so–called genetic scissors - the Cas9 enzyme, which dissects the DNA chain in the necessary places, and the guiding RNA molecule, which points the scissors to the target. Cas9 removes the target gene, and a healthy gene is usually inserted in its place.

In order for CRISPR to remove the desired gene, both components must work correctly. How to achieve the same accuracy on the scale of not one, but tens of thousands of cells?

Researchers have invented a method consisting in physically connecting thousands of guides with scissors, in the form of such a set they are precisely delivered to each cell.

At first, the method was tested to edit eight unique genes in yeast cells simultaneously. To evaluate the result, the authors sequenced the target DNA sites. The desired mutations were present in 95% of cases, which is an indicator of the high efficiency of the method.

Then the authors created a pool of more than 10,000 different pairs of the CRISPR system. They targeted sections of DNA – 1034 genes in each yeast cell that are considered vital. Each of these pairs replaced a certain section of a certain gene with a stop codon that stops the ribosome from working.

Every 24 hours for four days, scientists counted living and dead cells. The authors found that many genes that were previously considered vital to the cell are not.

The improvement of CRISPR technology will certainly help scientists quickly distinguish mutations of vital genes from harmless changes. The ability to edit a large number of different sections of DNA at the same time will eventually lead to the identification of mutations that are the true cause of a particular genetic disease.

Article by M. J. Sadhu et al. Highly parallel genome variant engineering with CRISPR–Cas9 is published in the journal Nature Genetics.

Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru .