New research shows that a controversial gene-editing experiment aimed at making children immune to HIV could also improve their ability to learn and form memories. The brains of two genetically engineered girls born in China last year could change for the better, improving cognitive abilities and memory, scientists say. The twins - named Lulu and Nana - appeared with modified genes, thanks to the efforts of Chinese scientists and the CRISPR tool.
Genetically modified twins from China
The study found that the same change that girls' DNA went through - the deletion of the CCR5 gene - not only makes mice smarter, but also improves the brain's ability to recover from a stroke, and may also be associated with better school performance.
“The answer is yes, it probably affected their brains,” says Alcino J. Silva, a neuroscientist at the University of California, Los Angeles. His lab discovered a major role for the CCR5 gene in memory and the brain's ability to form new connections.
“The simplest interpretation is that these mutations will affect cognitive function in twins,” says Silva. He also believes that the exact effect on girls' cognitive function is unpredictable and "not worth trying."
A team from China led by He Jiankui of the Southern University of Science and Technology in Shenzhen said they used CRISPR to remove CCR5 from human embryos, some of which were later used for conception. HIV needs the CCR5 gene to get into human blood cells.
The experiment has been widely condemned as irresponsible, and He is currently behind bars in China while his case is being investigated. News of the first genetically edited children also sparked rumors that CRISPR technology could one day be used to create superintelligent humans, perhaps as part of a biotech race between the United States and China.
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There is no evidence that He actually intended to change the twins' intelligence. MIT Technology Review contacted scientists researching the effects of CCR5 on cognition, and they say the Chinese scientist did not contact them hoping to get scientific advice or support - as they did with other groups of scientists.
“As far as I know, he didn't ask anything,” says Miu Zhou, a professor at Western University of California's Health Sciences.
Although He never consulted with brain researchers, the Chinese scientist was undoubtedly aware of the link between CCR5 and cognition. It was Zhou and Silva who showed this connection in 2016, finding that deleting the gene in mice significantly improved their memory. The team looked at over 140 different genetic changes to find out which made the mice smarter.
Silva says that due to his research, he occasionally met individuals in Silicon Valley and wherever he felt there was an unhealthy interest in designer babies with improved brains. That is why, when the birth of the twins went public on November 25, Silva says he immediately wondered if there was an attempt to make such a change. “I suddenly realized - my God, this is happening in earnest. My reaction was deep disgust and sadness."
During a meeting of scientists in the field of gene editing, which took place two days later in Hong Kong, he admitted that he already knew about all these possible consequences for the brain from a study at the University of California at Los Angeles. “I've seen this work, it needs more independent verification,” he replied after asking about it. "I am against using genome editing for improvement."
Whatever Xe's true goals may be, evidence continues to emerge that CCR5 plays an important role in the brain. Today, for example, Silva and a large group of American-Israeli scientists claim to have new evidence that CCR5 acts as a suppressor of memories and synaptic connections.
People with natural CCR5 deficiencies recover from strokes faster, according to their new study published in the journal Cell. What's more, those who lack at least one copy of this gene do better in school, meaning that it all affects everyday intelligence.
“We were the first to report CCR5 function in the human brain and improved academic performance,” said UCLA biologist Thomas Carmichael, who led the study. He calls the link to educational success “teasing,” but says it warrants further study.
The discoveries about CCR5 have already been followed by drug trials in patients with stroke and HIV, who sometimes suffer from memory problems. In these studies, one of which is being conducted at UCLA, people are given an anti-HIV drug - Maraviroc - that chemically blocks CCR5 to see if there is any improvement in their cognitive abilities.
Silva says there is a big difference between trying to correct deficits in these patients and trying to improve. “Cognitive problems are one of the pressing problems of medicine. Drugs are needed, but it is quite another matter to take normal people and change their DNA or chemistry to improve. We just don't know enough to do it. Nature has a very good balance."
Just because we don’t change ordinary intelligence doesn’t mean we cannot. Silva says genetic manipulation has created "smart mice" and has shown that not only is it possible, but that altering the CCR5 gene plays a big role in it.
“Is it possible that someday in the future we will be able to increase the average IQ of the population? I wouldn't be a scientist if I said no. Working with mice demonstrates that the answer is obvious - yes. But mice are not people. We just don't know what the consequences will be. We are not ready yet."
Ilya Khel