Editing DNA

A technique called CRISPR (Clustered regularly-interspaced short palindromic repeats) has been developed that allows scientists to edit DNA – in particular to cut out bits so that the changes will be passed on through generations.

The Week: The genetic breakthrough that could change humanity, explained

What is CRISPR?
It’s a revolutionary gene-editing technique that enables scientists to snip out a piece of any organism’s DNA cheaply, quickly, and precisely — cutting and editing the code of life the way a film editor would splice an old film reel.

In creating CRISPR, scientists learned to use Cas9 to cut out a target gene within any cell, replace it with another gene if needed, and neatly stitch the ends of the DNA back together.

As a result, genetic research is nearing a breakthrough that could transform the world.

It’s already being used…

… to make certain crops invulnerable to killer fungi, and scientists have also created a strain of mosquitoes with malaria-blocking genes that the insects successfully passed on to 99.5 percent of their offspring.

It could be used to change humankind.

But the technique’s most promising application is as a potential cure for hereditary diseases. In theory, scientists could use CRISPR to cure single-gene defects like Huntington’s by editing out the disease-carrying gene from the DNA of a fetus in the womb — permanently erasing the disease from the person’s germ line, so the offspring would also be saved.

Apart from the logistics of editing the DNA of sufficient numbers of fetuses to make a significant difference there are possible serious drawbacks.

A team at Sun Yat-sen University in Guangzhou attempted to modify the germ line in dozens of human embryos, hoping to snip out a defective gene that causes a deadly blood disorder.

The study caused shock waves in the scientific community — but also highlighted the practical difficulties of DNA editing in higher organisms.

Of the 86 embryos used — all of which were nonviable — just four manifested the new gene designed to replace the defective one.

Worse, there were inexplicable mutations in genes that weren’t targeted by the researchers. “The number of unintended effects is precisely why this technique is not appropriate for use in clinical applications,” bioethics professor R. Alta Charo told Wired.

So it could result in worse problems than it is intended to solve. And these problems might not become apparent for some time – a generation or more.

And then there’s the issue of whether it could lead to fiddling with human characteristics.

The larger question, of course, is whether scientists should be tinkering with the human gene pool at all.

At some point, researchers could switch their attention from curing hereditary diseases to editing supposedly desirable traits into a person’s DNA, such as high intelligence, tall stature, or blue eyes.

“Great things can be done with the power of technology — and there are things you would not want done,” said Jennifer Doudna, a Berkeley biologist who co-invented CRISPR. “Most of the public does not appreciate what is coming.”

We have already seen what can happen when people have their appearance changed using poisons and plastic surgery. You can end up with anything between bland and the ridiculous.

It can remove the humanness from once human faces. But at least the physical characteristics won’t be passed on to the next generation (although too much money and too little sense could be).

DNA editing has much wider and deeper implications – but not for me, it won’t affect my generation.

More on CRISPR at Wikipedia.

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3 Comments

  1. kiwi guy

     /  17th January 2016

    “CRISPR” – sounds like a bloody app, soon every smart phone user will all be able to engineer their own species in between Facebook and Pinterest.

    Reply
  2. A bit of CRISPR humanity wouldn’t go amiss here and there!

    Some CRISPY humanity too maybe?

    “Would you like Ultra-longevity fries with your Disease Resistant Gene burger sir?”

    “And to drink? GM smoothie or Stem Cell nectar?”

    Ding!!! “Times up sir. There’s 12,000 people waiting to be served.
    Please go to the back of the queue”.

    Reply

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