Reversing three genetic diseases in the animal model without even changing a single DNA letter. A Salk Institute team did it by bringing together two of biomedicine’s hottest trends. One is the CRISPR technique, which edits target genes through a programmable molecular machine named Cas9. The other is epigenetics, i.e., the study of chemical modifications that switch genes on and off without altering their sequence. It’s called epigenetic editing, because corrections are precise as in manuscript revision and occur at a level that is over (epi- in Greek) genetics. Continue reading →
When using a standard tape recorder you just have to press the buttons. Now a Columbia University team has devised a system for doing the same in living systems, recording changes taking place inside the cells. How does it work? This biological recorder, described in a study appearing in Science, is called TRACE and may help us chronicle what happens in open settings such as marine environments or in habitats difficult to access such as the mammalian gut. It records molecular fluctuations instead of sounds, capturing metabolic dynamics, gene expression changes and lineage-associated information across cell populations. The medium is DNA rather than magnetic tape. Sequencing is like playing. But how is the DNA recording done? Continue reading →
Suppose you have developed the winning weapon to defeat certain genetic diseases by reliably correcting pathogenic mutations. There is still a problem: how do you march onto the battlefield, inside sick cells? The weapon is the genome-editing machinery, and the most efficient vessel ever tested are lipid nanoparticles. With this approach, described in a study published in Nature Biotechnologylast week, CRISPR has beaten its success record in adult animals, knocking out the target gene in about 80% of liver cells. Continue reading →
The rising star of base editing shadowed classic genome editing last week. I’m sure you heard about the ground-breaking papers respectively published by David Liu and Feng Zhang in Nature and Science. CRISPR enthusiasts have probably already enjoyed the piece by Jon Cohen on the new approach, i.e., the rearrangement of atoms in individual DNA letters to switch their identity without even cutting the DNA strands. But let’s take a look also at The Scientist, which runs two must-read articles about the details of the experiments. The first take-home message is the latest achievements are exciting, but base editors are not better than CRISPR, they’re just different. The second one, there is still room for improvement with base editing, and the best is yet to come.
Biodiversity is a wonderful interplay between genetics and evolution, and butterflies are a fascinating example with their variety of patterns and colors. Understanding how the same gene networks engender visual effects so diverse in thousands of Lepidoptera species is a longtime ambition for many entomologists and evolutionary biologists. The good news is that scientists nowadays have a straightforward technique working with organisms that were difficult to manipulate with conventional biotech tools. Obviously, we are talking about CRISPR. Two papers published in PNAS last week describe how genome editing was used to alter the genetic palette of colors in butterflies and how their wings changed as a result. We’ve asked the entomologist Alessio Vovlas, from the Polyxena association, to comment these stunning experiments. Continue reading →
Spring in Japan is pink as cherry blossoms, but summer turns violet as the flowers of a climbing plant frequently grown in the gardens of the Rising Sun. It is a kind of morning glory, of the Ipomoea nil species, locally known as Asagao. This plant had its genome sequenced in 2016 and is now inaugurating the CRISPR era in floriculture. Continue reading →
It’s mid-August, but CRISPR never goes on vacation. Not to be missed this week is the Sciencepaper by George Church’s team. They have cloned 15 PERV-free piglets, meaning porcine retrovirus sequences have been edited out. The animals can now “serve as a foundation pig strain, which can be further engineered to provide safe and effective organ and tissue resources for xenotransplantation,” researchers write. According to the Harvard geneticist, the first pig-to-human transplants could occur within two years. Another article in the same journal feels the pulse of public perception of human genome editing, concluding that opinions are nuanced and the challenge is to find the best way to engage people in discussions about genome-editing regulation.