Scientists Create New, More Powerful Technique To Edit Genes

mr wonder · #1 (**permalink**) 10-21-2019, 10:11 PM

Scientists Create New, More Powerful Technique To Edit Genes

Quote:

Scientists have created a new way to edit DNA that appears to make it even easier to precisely and safely re-write genes.
The new technique, called prime editing, is designed to overcome some of the limitations of CRISPR. That technique, often described as a kind of molecular scissors for genes, has been revolutionizing scientific research by letting scientists alter DNA.

"It's proven difficult to use these molecular scissors to make precise DNA changes in most cell types," says David Liu, a biologist at Harvard, MIT and the Broad Institute in Cambridge, Mass.
Liu heads the lab where the new prime editing technique was created in research led by Andrew Anzalone. The advance is described in the journal Nature, in an article published Monday.
One advantage of the new editing technique is that, unlike CRISPR, prime editing doesn't rely on the ability of a cell to divide to help make the desired changes in DNA. That means it could be used to correct genetic mutations in cells that often don't divide, such as cells in the nervous system. Many diseases are caused by mutations in genes in those cells, such as Parkinson's and Huntington's diseases.
In addition, the new method doesn't cut both strands of the DNA double helix, minimizing the chances of making unintended changes that could be dangerous, Liu says.
"Prime editors are more like word processors capable of searching for targeted DNA sequences and precisely replacing them with edited DNA strands," Liu says.
Liu says his team has already used the new approach to perform more than 175 edits in human cells in laboratory dishes, including fixing genetic mutations that cause sickle cell disease and Tay-Sachs disease. Doctors are already trying to use CRISPR to treat sickle cell patients.
"Prime editing is really a step — and potentially a significant step — towards this long-term aspiration of the field in which we are trying to be able to make just about any kind of DNA change that anyone wants at just about any site in the human genome," Liu says.

The technique involves fusing two enzymes — one used in CRISPR known as CAS9 and another called reverse transcriptase. The combined enzymes are coupled with a molecule involved in decoding DNA known as RNA. In this case, the RNA, called pegRNA, is engineered to direct the editing enzymes to the target site in the DNA being edited and carries the new edited sequence.

Other researchers agree the new approach holds great promise.
"Prime editing may be a game changer," says Maria Jasin, a molecular biologist at the Memorial Sloan-Kettering Cancer Institute.
"It is a moment to stand up and cheer," agrees Fyodor Urnov, a geneticists at the University of California, Berkeley.
"For gene editors this feels a little bit like a new Avenger has joined our team. Someone who brings a super power that is needed for the field. Excited would be an understatement," Urnov says.
Urnov hopes prime editing will enable scientists to be able to fix mutations that cause diseases that CRISPR can't, such as mutations that occur in cells in the nervous system.
"If you think about CRISPR as flight — like a plane — then this new invention is kind of like a helicopter," Urnov says. "It also flies and gets you from point A to point B. But there are specific settings — like precisely landing at the top of the Salesforce tower here in San Francisco — where you could imagine that a helicopter would be better than a plane.

But Liu, Jasin and Urnov stress that it will take a lot more research to really know how well prime editing works. And that like any powerful new technology, it could potentially also be misused.
"Gene editing, like many technologies, can, in principle, be put to nefarious use. Prime editing in that regard does not pose an added grave danger to the planet," Urnov says. "That said, now is not the time for a sense of false security, but rather added vigilance."

https://www.npr.org/sections/health-...-to-edit-genes

cnredd · #2 (**permalink**) 10-22-2019, 12:12 AM

I hate articles like these...

This is a STEP n the process, NOT the endgame...

It gives a lot of false hope to people...

saltwn · #3 (**permalink**) 10-22-2019, 01:41 AM

ok
thought it said: edit games

intriguing breakthroughs
but my Catholic self wants to keep me in denial.

mr wonder · #4 (**permalink**) 10-22-2019, 07:05 AM

Quote:

Originally Posted by cnredd

This is a STEP n the process, NOT the endgame...
It gives a lot of false hope to people...

i hear ya.

My biggest concern is that they (we) still don't completely understand how the genome works. It was just a few years ago that that scientist were saying that 70-80% of the genome was "JUNK" ...useless left overs from "evolution". But now, after more research, they know better. And are saying that they understand that at least 80% of the gene IS in fact functional and they suspect that the other 20% has some yet unknown function as well. (making the the whole thing look very designed instead of evolved BTW) (as creationist and intelligent design folks predicted against the premature "junk DNA" assertions).

Plus, they've also have discovered another layer of complex functional coding in the genes they call "epigenetics".

Also, If my understanding is correct, they really just recently finished mapping the most of the genome. When they announced it's completion before it was just major parts.
(OK i just looked it up)

"The Human Genome Project originally aimed to map the nucleotides contained in a human haploid reference genome (more than three billion). The "genome" of any given individual is unique; mapping the "human genome" involved sequencing a small number of individuals and then assembling these together to get a complete sequence for each chromosome. Therefore, the finished human genome is a mosaic, not representing any one individual. "...The project was not able to sequence all the DNA found in human cells. It sequenced only euchromatic regions of the genome, which make up 92.1% of the human genome. The other regions, called heterochromatic, are found in centromeres and telomeres, and were not sequenced under the project.[26]
The Human Genome Project (HGP) was declared complete in April 2003. An initial rough draft of the human genome was available in June 2000 and by February 2001 a working draft had been completed and published followed by the final sequencing mapping of the human genome on April 14, 2003. Although this was reported to cover 99% of the euchromatic human genome with 99.99% accuracy, a major quality assessment of the human genome sequence was published on May 27, 2004 indicating over 92% of sampling exceeded 99.99% accuracy which was within the intended goal.[27] Further analyses and papers on the HGP continue to occur.[28]
In March 2009, the Genome Reference Consortium (GRC) released a more accurate version of the human genome, but that still left more than 300 gaps.[29]
As of June 2019, the GRC still indicates 89 "unresolved" gaps, most of which are annotated as "stalled" or "under investigation/review".[30] "
https://en.wikipedia.org/wiki/Human_..._of_completion

So yeah, they don't even have a 100% complete map, much less understand all the functions or the hard and soft wired functional interactions/coding of the genes sequences with each other.

It's like finding and highly advanced alien space ship ... tens of thousands of times more advanced that any human vehicle. Then taking it apart and trying to splice bits back together again and thinking they really know what the outcome will be.

Except that they are working on people instead of a an inanimate object.

Quote:

DNA is like a computer program but far, far more advanced than any software ever created.
Bill Gates

But we can "fix it"?
3+ billion parts of interactive human code... but software still crashes?
have i just watched to many sci-movies for me to trust the scientist on this?

cnredd · #5 (**permalink**) 10-22-2019, 01:26 PM

Quote:

Originally Posted by mr wonder

It's like finding and highly advanced alien space ship ... tens of thousands of times more advanced that any human vehicle. Then taking it apart and trying to splice bits back together again and thinking they really know what the outcome will be.

Except that they are working on people instead of a an inanimate object.

But we can "fix it"?

Oh, I believe there will be major advancements….SOMETIME down the line...

It's just that articles like these give the impression that we are "close", and nothing can be further from the truth...

I still remember, on my way to high school 30+years ago, that scientists have created a pill that dissolves fat in mice and they lost a tremendous amount of weight at lightning speed...

...See that on the market yet?...

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