healthHealth and Medicine

Groundbreaking Technique Fixes Genetic "Spelling Errors" And Deletes Diseases


Robin Andrews

Science & Policy Writer

The science of genetics has never been more powerful. Eetu Mustonen/Shutterstock

It’s unquestionable that humanity is the most powerful species on the planet. We are the kingmakers of the natural world, deciding almost everything’s fate – from aspects as gargantuan as the climate to those as minute as individual genes.

Speaking of which, the world of the invisible just got a lot more malleable this month thanks to the publication of two groundbreaking studies by teams at Harvard University’s and MIT’s Broad Institute. Both help to explain how gene editing has never been more precise, with what researchers are calling “chemical surgery” now available for use.


Genes are normally edited using something like CRISPR, a technique that allows experts to “cut and paste” DNA or RNA sequences in and out of the overall genome. This has been hailed as a landmark method that essentially allows us to customize the genetic framework of any living creature.

Now, as described in both papers, this new technique allows for editing with a much finer degree of precision. Instead of aiming at genetic sequences, it targets base pairs, couplings of molecules that are the building blocks of DNA.

Coming in four forms – adenine (A), cytosine (C), guanine (G) and thymine (T) – they represent the “alphabet” of life. Humans contain 3 billion base pairs, and if just one of the “letters” is incorrect – something known as a point mutation – it can cause diseases or medical afflictions that can be anything from life-changing to fatal.

The first paper, published in Nature, explains how tools named “base editors” can fix these errors.


The team explains how they used a modified CRISPR technique to achieve this. Using RNA, a chemical “cousin” to DNA, CRISPR unspools the base pairs in question, and chemically alters the incorrect letter in order to transform it into the correct one.

They tested this out successfully on a mutation found in human cells that causes the blood to contain hazardously high levels of iron. This suggests that the same technique could be used on the tens of thousands of other conditions that are linked to base pair mismatches.

A second paper, published in Science, again uses the power of RNA to chemically alter the A base, turning it into something called inosine (or “I”), a closely related compound. This technique – known as RNA Editing for Programmable A to I Replacement, or REPAIR – was used to cancel out a form of anemia that also affects human cells.

Together, these papers represent a huge step forwards in our ability to kill off diseases at the genetic level. Plenty more work is required, particularly when it comes to looking out for any unintended mutations these techniques might cause, but it’s a thrilling advance nonetheless.


[H/T: Guardian]


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