The brains of two genetically edited girls born in China last year may have been changed in ways that enhance cognition and memory, scientists say.
The twins, called Lulu and Nana, had their genes modified before birth by a Chinese scientific team using the new editing tool CRISPR. The goal was to make the girls immune to infection by HIV, the virus that causes AIDS. Now, new research shows the same alteration introduced into the girls’ DNA, to a gene called CCR5, not only makes mice smarter but also improves human brain recovery after stroke, and could be linked to greater success in school.
“The answer is likely yes, it did affect their brains,” says Alcino J. Silva, a neurobiologist at the University of California, Los Angeles. Silva’s lab has been uncovering a major new role for the CCR5 gene in memory formation and the brain’s ability to form new connections.
“The simplest interpretation is that those mutations will probably have an impact on cognitive function in the twins,” says Silva. He says the exact effect on the girls cognition is impossible to predict, and “that is why it should not be done.”
The Chinese team, led by He Jiankui of the Southern University of Science and Technology in Shenzhen, used CRISPR to delete CCR5 from human embryos, some of which were later used to create pregnancies. HIV requires the CCR5 gene to enter human blood cells.
He Jiankui poses for the cameras of the Associated Press in the days before his gene-editing experiments became known.
Mark Schiefelbein | AP
The China experiment has been widely condemned as irresponsible, and He is under investigation in China. However, the news of the first gene-edited babies also flamed speculation about whether CRISPR technology could one-day be used to create super-intelligent humans, including, perhaps, as part of a biotechnology race between the U.S. and China.
There is no evidence that He actually set out to modify the twins’ intelligence. MIT Technology Review contacted scientists studying the effects of CCR5 on cognition and they say the Chinese scientist never reached out to them, as he did others from whom he hoped to get scientific advice or support
“As far as I know, we never heard from him,” says Miou Zhou, a professor at the Western University of Health Sciences.
Although He never reached out to the brain researchers, the Chinese scientist was certainly aware of link between CCR5 and cognition, first shown in 2016 by Zhou and Silva, who found that removing the CCR5 gene from mice significantly improved their memories. The team had looked at more than 140 different genetic alterations to find which made mice smarter.
When the birth of the twins became public on November 25th, Silva says he immediately wondered if it had been an attempt to alter their brains.
Silva says because of his research, he sometimes interacts with figures in Silicon Valley and elsewhere who have, in his opinion, an unhealthy interest in designer babies with better brains. That’s why, when the birth of the twins became public on November 25th, Silva says he immediately wondered if it had been an attempt to alter their brains. “I suddenly realized, oh holy shit, they are really serious about this bullshit,” says Silva. “My reaction was visceral repulsion and sadness.”Whatever He’s true aims, evidence continues to build that CCR5 plays a major role in the brain. Today, for example, Silva and a large team from the US and Israel say they have new proof that CCR5 acts as a suppressor of memories and synaptic connections.
According to their report, appearing in the journal Cell, people who naturally lack CCR5 recover more quickly from strokes. What’s more, people missing at least one copy of the gene seems to go further in school, suggesting a possible role in everyday intelligence.
“We are the first to report a function of CCR5 in the human brain, and the first to report a higher level of education,” says UCLA biologist S. Thomas Carmichael, who led the new study. He calls the link to educations success “tantalizing” but says it needs to be further studied.
The discoveries about CCR5 are already being followed up in drug trials, both of stroke patients and people with HIV, who sometimes suffer memory problems. In those studies, one of which is underway at UCLA, people are being given an anti-HIV drug, Maraviroc, which chemically blocks CCR5, to see if it improves their cognitions.
Silva says there is a big difference between trying to correct deficits in such patients and trying to create enhancement. “Cognitive problems are one of the biggest unmet needs in medicine. We need drugs, but it’s another thing to take normal people and muck with the DNA or chemistry to improve them. We simply don’t know enough to do it,” he says. “Nature has struck a very fine balance.”
Just because we shouldn’t, doesn’t mean we can’t alter intelligence. Silva says the genetic manipulations used to make “smart mice” not only show that it’s possible, but that changing CCR5 has big effects.
“Could it be conceivable that at one point in the future we could increase the average I.Q of the population. I would not be a scientist if I said ‘no.’ The work in mice demonstrates the answer may be yes,” he says. “But mice are not people. We simply don’t know what the consequences will be in mucking around. We are not ready for it yet.”
