World.- Chinese scientist He Jiankui defends his work during a panel discussion at the Second International Summit on Human Genome Editing in Hong Kong. A controversial Chinese genetic experiment may have resulted in the creation of two babies with mutated genes, scientists warned.
Last year, biophysicist He Jiankui edited the DNA of twins named Lulu and Nana in an attempt to make them immune to HIV. But scientists have now claimed that the process may have failed and creating mutations with effects could be impossible to predict.
A particular gene called CCR5 was removed from its genetic code before birth. It has been shown that getting rid of this gene makes mice smarter and can have an effect on girls’ cognitive abilities. MIT Technology Review has published excerpts from a manuscript describing the research. Fyodor Urnov, genome-editing scientist at the University of California, Berkeley, said: «The claim that they have reproduced the prevailing CCR5 variant is a blatant misrepresentation of the actual data and can only be described by one term: a deliberate falsehood.» «The study shows that the research team failed to reproduce the prevailing CCR5 variant.» The Chinese scientist tried to publish his manuscript in prestigious journals such as Nature and JAMA, but they have not yet accepted it. Earlier this year, scientists said girls were likely to grow up with different brain powers than they would have done without gene editing.
«The answer is probably yes, it did affect their brains,» Alcino J. Silva, a neurobiologist at the University of California, Los Angeles, told the MIT Technology Review. «The simplest interpretation is that those mutations are likely to have an impact on cognitive function in twins,» said Silva, whose lab discovered a major new role for the CCR5 gene in memory and the brain’s ability to form new connections. The HIV virus requires the CCR5 gene to enter human blood cells.
But one of the reasons why this type of editing should not take place, Silva argues, is uncertainty about how this will affect girls’ brains over time. It is unclear whether He Jiankui, who led the CRISPR experiment last year, intended to try to affect the intelligence of babies. He, from the University of Southern Science and Technology in Shenzhen (which denied knowing about the work) defended the experiment despite the condemnation of the scientific community at large. Nobel laureate David Baltimore said Professor He’s work would be «considered irresponsible» because it did not meet the criteria that many scientists agreed several years ago before gene editing could be considered. Baltimore said he didn’t think it was medically necessary. He said the case showed that «the scientific community has failed in self-regulation» and said the conference committee will meet and issue a statement on Thursday about the future of the field. One screen shows genomic data from the He Jiankui Experiment (AP) The National Health Commission ordered local officials in Guangdong province to investigate the actions of He, and his employer, the University of Southern Science and Technology, is also investigating.
The Chinese researcher said he practiced editing embryos of mice, monkeys and humans in the lab for several years and has filed patents on his methods. He said he chose the edition of embryonic genes for HIV because these infections are a big problem in China.
Either way, it’s going to be a long time before we know for sure what the brain impacts of the experiment are. ‘Could it be conceivable that at some point in the future we can increase the average IQ of the population? It wouldn’t be scientific if I said no,» Silva concludes. Working on mice shows that the answer can be yes,» he said. ‘But mice are not people. We just don’t know what the consequences will be in the move. We’re not ready for it yet.