The “new CRISPR” is here and it promises to fix 89% of genetic defects

What: Harvard scientists announced a new gene-editing technique that could reportedly correct 89% of known genetic defects.

Why: The technique is meant to improve on CRISPR-Cas9, currently the most popular DNA editor. The main problem of CRISPR-Cas9, often described as “a pair of DNA scissors”, is that it leaves a lot of room for error alongside the changes it makes to the genome.

How: The new technique, called “prime editing”, promises to fix that. It does so without breaking the DNA strand as is the case with the current method.

Prime editing “in principle could correct about 89% of known pathogenic human genetic variants”, according to a paper authored by a team of geneticists at Harvard, MIT, led by Dr. David Liu.

“We applied prime editing in human cells to correct efficiently and with few byproducts the primary genetic causes of sickle cell disease […] and Tay-Sachs disease […]”, the researchers say.

MIT Technology Review quotes Liu as saying that thanks to the technique and the “molecular gadget” developed by his team, they are now able to repair “nearly any of the 75,000 known mutations that cause inherited disease in humans.”