Another CRISPR havoc? That’s science, baby


A paper published in Nature Biotechnology by Allan Bradley and colleagues from the Wellcome Sanger Institute in Hinxton, UK, shows that classical CRISPR editing can cause large rearrangements of DNA near the target site in actively dividing cells. We may think of it as the latest CRISPR alarm, but also as a demonstration of how biomedical research works. Firstly: no technology is perfect, but the best ones are perfectible. CRISPR belongs to this category because it is an extraordinarily versatile and fast-evolving biotech platform. When reading news like “CRISPR causes this or that problem,” the first question to ask is: which CRISPR variant are we talking about? Continue reading

Three hopes for CRISPR

easter eggs

Off-target paper retraction: Nature Methods has retracted a controversial study questioning CRISPR precision, after its authors admitted they were probably wrong. This blog’s wish is that future studies on CRISPR flaws and virtues are as reliable as the genome-editing technique.

Deregulation statement: US Secretary of Agriculture Sonny Perdue has announced that USDA will not regulate edited plants as long as they could have been created through conventional breeding. Let’s hope Europe will follow the example.

Gene therapy going “organic”: that’s the hope expressed by Merlin Crossley, when commenting his Nature Genetics paper on mutations beneficial to patients with β-thalassemia and sickle cell anemia. The word organic here means that fetal hemoglobin production can be boosted without inserting foreign DNA.

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