In this file:
· The CRISPR machines that can wipe out entire species
… we are still coming to terms with how powerful CRISPR gene drives might be. Playing the game of genomes means we may, in the future, choose which species live and which die -- a near-unbelievable capability that scientists and ethicists agree presents us with unique moral, social and ethical challenges…
· New Anti-CRISPR Proteins Discovered in Soil, Human Gut
… some anti-CRISPR proteins are more widespread in nature than previously anticipated. These anti-CRISPRs can potentially be used to regulate the activity of CRISPR-Cas9 systems…
The CRISPR machines that can wipe out entire species
The genetic-engineering tool could help combat malaria and invasive species. But should we use it?
by Jackson Ryan, CNET Magazine
February 6, 2019
Charles Darwin had no idea what a gene was. If we dropped the father of evolution into 2019, the idea that humans can willfully alter the genes of an entire species would surely seem like wizardry to him.
But CRISPR gene drives -- a new, inconceivably powerful technique that forces genes to spread through a population -- have the ability to do just that. Gene drives allow us to hone the blunt edges of natural selection for our own purposes, potentially preventing the spread of disease or eradicating invasive pests.
Yet as with any science performed at the frontier of our knowledge, we are still coming to terms with how powerful CRISPR gene drives might be. Playing the game of genomes means we may, in the future, choose which species live and which die -- a near-unbelievable capability that scientists and ethicists agree presents us with unique moral, social and ethical challenges.
But first, let's talk about genetic engineering.
Humans have been interfering with genetics for millennia. We domesticated dogs, we bred gigantic chickens. But during the 20th century, we learned genes were made of DNA and we created tools that allow us to tinker with them. By the 1970s, that had opened up a new field of research.
Over the next 40 years, genetic engineering became commonplace for scientists. It hasn't been easy. Successfully inserting or deleting genes required time, high-level expertise and a big wallet. But in 2012, with the discovery of CRISPR, genetic engineering became cheaper, faster and more efficient.
Now scientists possess a robust molecular tool that can reliably alter genes in almost any organism. It was touted as a revolution in 2013 -- and it has been, enabling genetic modification of crops, potential new cancer treatments, refining antibiotics and new ways to create animal models of disease.
And CRISPR is being turned against some of the biggest ecological problems in the world by combining it with a "gene drive," a powerful genetic engineering tool used to spread genes through an entire population. Within just five years, CRISPR gene drive technology has gone from pioneering idea to impending reality.
In London, a team of researchers is trying to perfect a drive that could wipe out entire populations of the malaria-carrying Anopheles mosquito, combating a disease that according to the World Health Organization kills almost half a million people every year. Meanwhile, in Australia, a scourge of poisonous cane toads hop their way across the continent, endangering native species. Researchers hope to render their toxins inert and control their spread, giving the natural flora and fauna a chance to bounce back.
A world without malaria. A planet without invasive species.
With gene drives, we can tame evolution.
Real monsters ...
The origin of changing species ...
Full collapse ...
The toxic toad ...
Nuts, bolts, warts and all ...
Fielding questions ...
The game of genomes ...
more, including links
New Anti-CRISPR Proteins Discovered in Soil, Human Gut
by Technical University of Denmark
via LaboratoryEquipment.com - 02/06/2019
The new study published in Cell Host & Microbe suggests that some anti-CRISPR proteins are more widespread in nature than previously anticipated. These anti-CRISPRs can potentially be used to regulate the activity of CRISPR-Cas9 systems better in the future.
CRISPR systems are bacterial immune systems that enable the bacterium to fight off infecting viruses (phages) in a targeted manner.
Due to their programmable nature CRISPR systems, and in particular Cas9, are currently being widely deployed in the life science industry with the potential to deliver breakthrough gene therapies, new antibiotics and malaria therapies.
Interestingly, phages have evolved anti-CRISPR proteins to overcome bacterial CRISPR systems in the evolutionary arms race between viruses and bacteria. These proteins quickly inhibit the host bacterium's defence system leaving the bacterium vulnerable to infection.
In spite of their significant biological importance, only a few anti-CRISPR proteins have been discovered so far in a very specific subset of bacteria. Current anti-CRISPR proteins are not abundant in nature. and have been identified by studying the DNA of the phages that were able to infect bacteria harbouring CRISPR-Cas9. Using this method, one relies on being able to culture bacteria and on phages that are able to infect and avoid the surveillance of the endogenous CRISPR Cas9-system.
"We used a different approach that focused on anti-CRISPR functional activity rather than DNA sequence similarity. This approach enabled us to find anti-CRISPRs in bacteria that can't necessarily be cultured or infected with phages. And the results are really exciting," says Ruben Vazquez Uribe, Postdoc at the Novo Nordisk Foundation Center for Biosustainability (DTU).
The researchers identified the anti-CRISPR genes by using the total DNA from four human fecal samples, two soil samples, one cow fecal sample and one pig fecal sample. The DNA was chopped into smaller pieces and randomly expressed on a plasmid within a bacterial cell. This cell contained a genetic circuit for selection of anti-CRISPR activity. In short, this meant that cells containing a plasmid with a potential anti-CRISPR gene would become resistant to a certain antibiotic. On the contrary, cells in which the plasmid did not confer anti-CRISPR-activity would die. With this system, the researchers could easily detect and select DNA with anti-CRISPR activity and trace it back to its origin.
Using this metagenomic library approach, the scientists were able to identify eleven DNA fragments that circumvented Cas9 activity.
Further characterization could then confirm the activity of four new anti-CRISPRs. Phylogenetic analysis revealed...