Korva is a scroll of the internet’s best ideas.
The Experiment
The scientist is named He, and he had done his postdoctoral training at Stanford before moving on to his own lab in China. The story was that the babies' father was HIV positive and he wanted to save the children from HIV AIDS. The technology for this already existed, and he went all the way to the end experiment.
The Reaction
Nobody in the medical science community knew how people would react, and some wondered whether he would get a Nobel Prize or be thrown in jail. Colleagues who had exchanged emails with him found those emails dug into. Many of the messages told him to be careful and then asked whether it was working.
The Open Question
The HIV receptor is supposedly also linked to some aspects of neural circuit formation tied to memory. Neuroscientists privately wondered whether the aim was both to make the children immune to HIV infection and to make them smarter. No one has answered that question conclusively.
The world decided that ethically this was bad, and the Chinese government announced that his lab would be taken away and that he would be punished. Purportedly, he now runs a laboratory in Austin, Texas.
Why did the edit target the HIV receptor?
The receptor is a protein called CCR5, which most HIV strains use as a doorway into immune cells. Some people of northern European descent carry a naturally occurring deletion in the gene, called CCR5-delta32, and are highly resistant to infection with those strains. Timothy Ray Brown, known as the Berlin patient, was cleared of HIV after a bone marrow transplant in 2007 from a donor with that deletion.
Why does editing embryos worry scientists?
Changes made to an embryo are copied into every cell and passed to future generations, unlike edits to one patient's tissue. CRISPR can also cut at unintended sites, or edit only some of an embryo's cells, a result called mosaicism. In 2015, an international summit on human gene editing in Washington, D.C., said it would be irresponsible to use germline editing clinically until safety questions were settled.
How does CRISPR find the right gene?
A protein called Cas9 is steered by a short piece of RNA whose sequence matches a stretch of DNA. When the guide finds its match, Cas9 cuts both strands of the double helix. The cell patches the break with a repair process that is error-prone, which often disables the gene. Jennifer Doudna and Emmanuelle Charpentier received the 2020 Nobel Prize in Chemistry for developing the method.
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