The brains of two genetically modified girls born in China last year may have changed in ways that improve cognition and memory, scientists say.
The twins, named Lulu and Nana, have reportedly changed their genes before birth by a Chinese scientific team using the new CRISPR editing tool. The goal was to make the girls immune to HIV infection, the virus that causes AIDS.
Now, new research shows that the same change introduced in the girls’ DNA, removing a gene called CCR5, not only makes mice smarter, but also improves human brain recovery after a stroke, and can be linked to greater success at school.
“The answer is probably yes, it did affect their brains,” says Alcino J. Silva, a neurobiologist at the University of California, Los Angeles, whose laboratory has discovered an important new role for the CCR5 gene in The memory and ability of the brain to form new connections.
“The simplest interpretation is that those mutations are likely to have an impact on cognitive function in the twins,” says Silva. He says that the exact effect on girls’ cognition is impossible to predict, and “that’s why it shouldn’t be done.”
He Jiankui poses in front of the cameras of the Associated Press in the days before his experiments with gene editing became known.
Mark Schiefelbein | AP
The Chinese team, led by He Jiankui of the Southern University of Science and Technology in Shenzhen, claimed it used CRISPR to remove CCR5 from human embryos, some of which were later used to create pregnancies. HIV requires the CCR5 gene to invade human blood cells.
The experiment is generally condemned as irresponsible and is being investigated in China. The news of the first gene-processed babies also caused speculation as to whether CRISPR technology could ever be used to create super intelligent people, perhaps as part of a biotechnology race between the US and China.
There is no evidence that He actually wanted to change the intelligence of the twins. MIT Technology Review contacted scientists who were studying the effects of CCR5 on cognition, and they say the Chinese scientist never contacted them, as he did with others from whom he hoped to get scientific advice or support.
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“As far as I know, we’ve never heard of him,” says Miou Zhou, professor at the Western University of Health Sciences in California.
Although he has never consulted brain researchers, the Chinese scientist was certainly aware of the link between CCR5 and cognition. It was first shown in 2016 by Zhou and Silva, who discovered that removing the gene from mice significantly improved their memory. The team had looked at more than 140 different genetic changes to discover which mice were smarter.
Silva says that due to his research he sometimes has contact with figures in Silicon Valley and elsewhere who, in his opinion, have an unhealthy interest in designer babies with better brains. That is why Silva, when the birth of the twins was revealed on November 25, immediately wondered if it had been an attempt at this kind of change. “I suddenly realized – Oh, shit, they’re really serious about this nonsense,” Silva says. “My reaction was visceral rejection and sadness.”
At a summit of genetics scientists who took place two days later in Hong Kong, he acknowledged that he had always been aware of the possible brain effects of UCLA research. “I saw that paper, it needs more independent verification,” he replied when asked about it during a Q&A session (see video here). He added, “I am against using genome editing for improvement.”
Whatever his true goals are, evidence remains that CCR5 plays an important role in the brain. Today, for example, Silva and a large team from the US and Israel say they have new evidence that CCR5 works as a suppressor of memories and synaptic connections.
According to their new report, published in the journal Cell, people who naturally miss CCR5 recover faster from strokes. In addition, people who miss at least one copy of the gene seem to go on to school, suggesting a possible role in daily 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,” said UCLA biologist S. Thomas Carmichael, who led the new study. He calls the link to training success ‘tempting’, but says it needs to be studied further.
The discoveries about CCR5 are already being followed in drug research in both stroke patients and people with HIV, who sometimes have memory problems. In those studies, one of which is underway at UCLA, people are given an anti-HIV drug, Maraviroc, that chemically blocks CCR5, to see if it improves their cognition.
Silva says there is a big difference between trying to correct deficits in such patients and trying to create improvement. “Cognitive problems are one of the greatest unmet needs in medicine. We need medication, but it’s something else to take normal people and ruin DNA or chemistry to improve them, “he says.” We just don’t know enough to do it. Nature has found a very good balance. “
Just because we should not change normal intelligence does not mean that we cannot. Silva says that the genetic manipulations used to make “smart mice” not only show that it is possible, but that changing CCR5 has particularly large effects.
“Could it be conceivable that we could raise the average IQ of the population at some point in the future? I wouldn’t be a scientist if I said no. The work in mice shows that the answer can be yes, “he says. “But mice are not people. We just do not know what the consequences will be if we are around. We are not ready for it yet. “
