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  • With all the hubbub about CRISPR in the news, it may feel like using it to pick your kids

  • eye-color is just around the corner.

  • But this seemingly miraculous gene-editing technology may not actually be as simple--or

  • as safe--as we thought.

  • Just so we're all on the same page, CRISPR (or more accurately CRISPR-cas9) works by

  • cutting the DNA of a cell at a designated spot, say a section of DNA that represents

  • a certain gene.

  • Then, when the cell tries to repair the damaged DNA, it often ends up just disabling the gene

  • altogether.

  • This has all kinds of uses.

  • Maybe we want to turn off a gene that produces too much of a certain protein?

  • CRISPR can do that.

  • Say we want to see what a certain gene even does?

  • CRISPR can help us do that too.

  • Ever since it was first used to edit living cells in 2013, CRISPR has been touted as a

  • promising technology for treating inherited disorders, cancer, and other diseases with

  • no current treatment options.

  • Teams of researchers around the globe had even hoped to begin human trials in 2018.

  • But none of those trials have taken place yet, with the exception of China, where researchers

  • have been working with CRISPR in humans since 2016--no results from these trials have been

  • published so far.

  • And in the US, the FDA just placed a 'clinical hold' on the first proposed CRISPR gene

  • editing human trial.

  • But why?

  • Several new studies released in the last few months suggest we need to be more cautious

  • when editing the human genome.

  • Two of these studies found that when CRISPR performs its hallmark trick and cuts DNA,

  • that damage can kill the cell, or make it stop growing.

  • CRISPR modifications are also less likely to kill cells that have a defective version

  • of a gene called p53.

  • P53 plays a role in preventing the onset of cancer by regulating a cell's life cycle,

  • so by leaving more of the defective cells alive than healthy ones*, CRISPR may be inadvertently

  • raising the risk of cancer in that patient.

  • Which is, like, the opposite of the goal.

  • And we haven't even gotten to the most recent study that raises concerns.

  • Up until now, CRISPR-cas9's cutting function has been accurate in the specific area of

  • interest--the spot in the DNA that's supposed to be cut.

  • But that's because researchers were only looking for mutations caused by CRISPR in

  • the immediate vicinity of the cut.

  • New research reveals that in about 20% of cells, CRISPR results in MUCH larger deletions

  • than we thought**-- up to more than 100 base pairs.

  • Researchers didn't notice this before because they were looking for harmful mutations and

  • didn't see any...but that's because the entire region was gone.

  • In CRISPR treatments that would target billions of cells inside the human body, this could

  • lead to, again...a risk of cancer.

  • Putting us right back at square one.

  • So the human trials have been delayed...where do we go from here?

  • CRISPR permanently alters your genome, so we want to make sure we get it right before

  • we make moves in real human bodies.

  • Well, science marches on.

  • New and improved versions of this kind of technology are already racing forward, like

  • a genetic editing tool called REPAIR, which uses a different cutting enzyme--Cas13.

  • REPAIR works with RNA, instead of DNA, to make temporary or reversible changes.

  • There's also a newly engineered protein that can alter individual base pairs rather

  • than a whole chunk of DNA, acting more like surgical forceps than a pair of kitchen scissors.

  • So continued progress and exciting breakthroughs in this field are still happening--we're

  • not at the end of our CRISPR rope yet.

  • It's just that we need to take a step back from the hype and carefully analyze what's

  • really going to be safe as we move forward.

  • To stay current with all the CRISPR news that's sure to be plentiful in the coming years,

  • subscribe to Seeker, and for more on how your body, specifically your immune system, interacts

  • with the technology, check out this video from Julian.

  • And, fun fact, CRISPR doesn't just present possibilities in human biology--it could be

  • used to produce genetically crops too.

  • I'm Maren, thanks for watching Seeker.

With all the hubbub about CRISPR in the news, it may feel like using it to pick your kids

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CRISPR适得其反时会发生什么(What Happens When CRISPR Backfires?)

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    joey joey 發佈於 2021 年 04 月 17 日
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