Doudna & Charpentier · CRISPR
Should we be allowed to edit life's letters?
That time, that place
Bacteria have immunity too.
When a virus invades, the bacterium cuts a piece of the viral genome and files it into a stretch of its own — a kind of wanted list. If the same virus returns, the stored piece serves as a guide, and the invader's DNA is cut at exactly that spot.
Why this question
What Doudna and Charpentier recognized was the architecture of this system.
The cutting tool and the guide that specifies where to cut are separate. So if you swap in a different guide, the same tool should cut wherever you choose.
What was found
They reproduced the system in a test tube and showed that swapping the guide sequence makes the tool cut wherever that guide points.
Editing a gene had taken years and considerable money. It now took weeks, within reach of an ordinary laboratory.
And trouble followed quickly.
In 2018 a researcher in China announced that babies had been born from edited human embryos. The international community condemned it and he was imprisoned.
The issue is clear enough. Editing the cells of someone already alive ends with that person. Editing an embryo passes the change to every descendant — altering the bodies of people who cannot consent.
Editing a gene at a chosen site was too difficult to be routine
Test-tube experiments cutting at chosen sites once the guide sequence was swapped
The two received the 2020 Nobel Prize in Chemistry. Real results are arriving in treating genetic disease, while agreement on where the limits lie has not been reached