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

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

CRISPR meets machine learning

If a donor template is not provided when CRISPR cuts the DNA, broken ends are fixed by natural repairing mechanisms in a way that is considered stochastic and heterogeneous. This makes template-free editing impractical beyond gene disruption, right? Wrong, according to a study published in Nature by Richard Sherwood and colleagues. Continue reading

Do we need a Global Observatory for Gene Editing?

osservatorio globale NatureEveryone knows IPCC, the forum created under the auspices of the United Nations to review the state of knowledge on climate change, draw scenarios on its impact, and compare alternative policies. Does the world need a similar body for the biotech revolution ahead, as claimed by Sheila Jasanoff and J. Benjamin Hurlbut in Nature? Is a Global Observatory on Gene Editing the solution to our CRISPR troubles? We asked a pioneer of gene therapy and a pioneer of gene drives, but also a bioethicist, a political scientist, a social psychologist, a science historian. Continue reading

xCas9: CRISPR gets easy-going

pam sequenceCRISPR needs to anchor itself near a short sequence called PAM to do its job. In the book “Modern Prometheus” (Cambridge University Press) James Kozubek says a PAM is like a shoehorn, where the Cas9 nuclease begins to clasp down to recognize the right site and cut. In order to fit every gene, a super-adjustable shoehorn would be needed. Think of it as the equivalent of a bump key that can open any door. A Broad Institute group led by David Liu has almost reached the goal with xCas9, the new super-adjustable Cas9 variant described in Nature this week. Continue reading