‘Softer’ form of CRISPR may edit genes more accurately

Carissa Wong is a person.

There is a new form of the genome-editing technique called CRISPR. The approach was tested in fruit flies and was able to fix a genetic problem on one copy of a chromosomes.

It is possible to cut through two strands of a DNA molecule with the help of a molecule called Cas9. New genes can be inserted between the old ones.

Incorrect, or off-target, regions of the genome can cause less than 10% of cells to be inserted.

The University of California, San Diego, and their colleagues have developed a new form of CRISPR that can be used to insert correct DNA at the site of a mutations.

The person says he was blown away. Roughly 1 percent of edits are mistakes or off-target with existing CRISPR techniques. It would be more like 1 in 10,000.

The method only cuts a single strand of the double helix with a variant of the Cas9 enzyme. A clean double-stranded break is more efficient than a soft nicking of one strand of the genome.

The approach was tested in fruit flies that had a different eye color. The flies were given red eyes because of the nickase system's correction of the eye colour. Each eye had a small patch of red as a result of Standard CRISPR usingCas9.

It was amazing. When we saw that, we knew we had found something special.

The team didn't introduce any extra pieces of DNA as a template for the cell, so the machinery must have used the other parent's chromosomes as a template This was confirmed by the team.

It was not thought to be possible to repair one of the chromosomes with the other one. Recent findings show that this can sometimes happen under certain circumstances.

There is evidence that when you damage one of the chromosomes in a cell, you recruit the other one. The Band-Aid comes from the other chromosome.

What is the responsibility for doing that? The work opens up an avenue of discovering the whole set of components that are responsible for this new type of repair.

If it is proven to work in people, the approach could potentially be used to repair disease-linked genetic defects. It won't be able to fix the X chromosomes in boys and men who don't have a second copy. It won't work for people with the same disease link on both chromosomes from their parents.

Science Advances is a journal published by Science Advances.