Evolving high fidelity CRISPR


credit Alessio Coser

It’s called evoCas9, and it’s the most accurate CRISPR editing system yet, according to a study just published in Nature Biotechnology. Researchers at the University of Trento, in northern Italy, induced random mutations in vitro on a piece of a bacterial gene coding for the DNA-cutting enzyme (the REC3 domain of SpCas9) and then screened the mutated variants in vivo in yeast colonies by looking at their color. If the molecular scissors work properly, cutting only the right target, the yeast becomes red, but colonies are white if CRISPR cuts off target. Continue reading

Clearing CRISPR of off-target suspicion

mathcrisprFaster, better, cheaper is a motto adopted by Nasa that perfectly fits CRISPR as well. The most popular technique for genetic modification, in fact, has the reputation of being quick, affordable and precise. This deserved good name was unexpectedly tarnished by a study questioning the technology precision, published in the June issue of Nature Methods. However, reports about CRISPR’s demise have been greatly exaggerated, to paraphrase Mark Twain. Just over a month later, three analyses challenging the controversial study are already available in the pre-publication archive bioRxiv, and Nature Methods has alerted its readers about the criticisms received by publishing an editorial note which could turn into a retraction. Continue reading

Nobody’s perfect. Neither CRISPR nor peer-review

nobodyPerfection is not of this world, and no technology is perfect. But tolling the bell for CRISPR because of a single preliminary study last week was premature at best. Many voices are doubting the meaning of the Nature Methods paper reporting “hundreds of unintended mutations” putatively caused by genome editing. Some researchers have already announced that critical analyses and rebuttals are forthcoming. Continue reading