The M-word and a CRISPR divorce

French microbiologist Emmanuelle Charpentier (L) and professor Jennifer Doudna of the U.S. pose for the media during a visit to a painting exhibition by children about the genome, at the San Francisco park in OviedoWhere is Jennifer Doudna? This is the first thought most journalists had – me included – when reading the list of signatories to the call for the moratorium on heritable genome editing just published by Nature. The Boston team is well represented by Lander, Zhang and Liu (nobody would expect George Church to join that call). But the magnificent couple Doudna-Charpentier has conspicuously split up. Continue reading

CasX: the smaller the crispier

cas treeTime will tell if it is going to become the preferred enzyme for genome editing or just another useful tool in the expanding CRISPR kit. But the future of CasX looks bright. It is much smaller than the nucleases that have provided a foundation for this technology. Being fewer than a thousand amino acids, it offers clear advantages for delivery in comparison with Cas9, that is over 1,300 Aa. Continue reading

From chili pepper to hot tomato?

this image shows jalapeño peppers (a cultivated variety of capsicum annuum) credit emmanuel rezende naves

Chili peppers have happily entered our kitchens with their capsaicinoid content, since Cristoforo Colombo brought then back from Central America. Capsicum species however are labour-intensive and difficult to grow. They are also notoriously recalcitrant to biotechnological intervention. Tomatoes are much handier in comparison. The Capsicum and Solanum clades split at least 19 Mya ago but comparative genomics has revealed that tomatoes retain all the necessary genes for pungency. Why not to harness CRISPR power to turn tomatoes into capsaicinoid biofactories then? Continue reading

CRISPR best and worst in 2018

CRISPR contributed to Science’s Breakthrough of the Year and was also nominated for the Breakdown category by the same journal. The second nomination was an easy guess: He Jiankui and its baby-editing claim were also mentioned in Nature’s 10 for 2018. Much more interesting is the decision to celebrate cell-barcoding, the CRISPR-based technique used to track embryo development in stunning detail and over time. Continue reading

CRISPR seeds: the asexual revolution is now

apomictic rice UC Davis

Imtiyaz Khanday (left), Venkatesan Sundaresan (right)  with their apomictic rice  (credit: KARIN HIGGINS/UC DAVIS)

“To make a seed it takes a fruit,” pupils use to sing in Italy. Then students learn that there is an embryo inside seeds and it takes a pollen fertilized egg to make it. The dream of plant scientists, however, has always been to be able to produce seeds using only the cell egg. This dream has finally come true: a group led by Venkatesan Sundaresan, at UC Davis, has developed a rice variety capable of cloning its seed. Continue reading

Another CRISPR havoc? That’s science, baby

keep-calm-and-sequence-dna

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

CRISPRing the Neanderthal’s mind

Neanderthal_minibrains

Sapiens vs Neanderthalized brain organoids (credit A. Muotri)

Taking a peek into the brain of a Neanderthal specimen would be a dream for whoever is interested in the evolution of human intelligence. To get an idea of the cognitive abilities of our closest relatives, so far, anthropologists and neuroscientists could only study the fossil and archaeological record, but a new exciting frontier is opening up where paleogenetics meets organoids and CRISPR technologies. By combining these approaches, two labs are independently developing mini-brains from human pluripotent stem cells edited to carry Neanderthal mutations. Alysson Muotri did it at UC San Diego, as Jon Cohen reported in Science last week. Svante Pääbo is doing it at the Max Planck Institute in Leipzig, as revealed by The Guardian in May. Forget George Church’s adventurous thoughts on cloning Neanderthals. The purpose here is to answer one of the most captivating questions ever asked: did the mind of these ancient men and women, who interbred with our sapiens ancestors before going extinct, work differently from ours? Last but not least, with respect to the ethics of experimenting with mini-brains, don’t miss the perspective published in Nature.