Last year, when Chinese scientist He Jiankui edited genes for two embryos that would grow into Lulu and Nana, he was on behalf of that to protect the two girls from HIV; disease that the little girl's father had.
The scientist said he did not want girls born to carry the virus that causes AIDS, so that they had to receive a lot of discrimination in a country like China.
But that identity has now been pushed down. A new study published in Nature Medicine shows that genetic modifications that He Jiankui creates may put two girls at a risk separate from HIV infection.
Accordingly, people with mutations in this gene have a 21% higher risk of premature death before they reach the average age.
"Jiankui was very rash when choosing this gene to create mutations, so he could harm the life of two children.", Robin Lovell-Badge, British stem cell scientist from Francis Crick Research Institute, said.
Scientist He Jiankui – who edited the first human embryos in the world
The mutation delta-32 – which He Jiankui targets – can actually help people with HIV resistance, but when and only if it occurs on both copies of the CCR5 gene. A copy is inherited from the father and a copy from the mother. In it, a copy of the mutation provides somewhat weaker protection.
Researchers at the University of California, Berkeley have searched for this popular CCR5-delta-32 mutation in the database of more than 400,000 middle-aged volunteers in the UK.
In that database, people carrying two copies of the natural mutant gene were found to be 20% more likely to die at age 76, compared to those with only one copy or no copies. .
In addition, there are fewer volunteers with double mutations than expected. This suggests that people who carry both delta-32 mutations in CCR5 are dead or inadequate to volunteer, April Wei, the study's lead author said. He is an evolutionary geneticist currently doing postdoctoral research at the University of California, Berkeley.
"NWhat we found was that these mutations significantly increased mortality"Said Rasmus Nielsen, a co-author of the study."We were quite surprised that this effect was so big. "
Wei said scientists like him could not explain the relationship between these gene mutations and shortened life expectancy. But this effect may stem from a greater risk of multiple viruses such as West Nile flu and virus.
Mutations in CCR5 can block HIV virus, but it can also reduce life expectancy
He Jiankui's experiment marked a milestone, where, for the first time, human embryos were modified and then developed into a real child. Before this time, there were adults who were genetically modified, but these changes were not passed on to future generations (unless they were reproductive cells).
Human gene editing – done as a medical treatment in these preliminary studies – is considered a promising method. However, the work that scientist He Jiankui did is different.
He changed the genetic code of the embryos, and these changes will be passed on to future generations. Some scientists bluntly call it immoral action, while some other scientists, including Lovell-Badge, see some benefits of this.
Editing an embryonic gene can help children who are immune to certain unavoidable diseases. But the vast majority of scientists still believe that this time is too early to use that technique.
The global scientific community was very angry at the news that a Chinese scientist has overcome the rules to correct human embryonic genes, even raising them into two complete children. The World Health Organization, a number of national academies and scientific groups have called for a global ban on this genetic modification.
As for He Jiankui, he was fired from his position at the Huainan University of Science and Technology in Shenzhen. There is also information that He Jiankui has been arrested and placed under house arrest, before facing a possible sentence of death.
But last week's news from Dr. William Hurlbut, a Stanford biologist, told STAT, he has kept in touch with the Chinese scientist since He Jiankui was fired and placed under house arrest.
After announcing the experiment of two genetically modified girls, a Dubai fertility clinic wanted He Jiankui to share his technique. Dr. Hurlbut advised him not to do so.
He Jiankui was fired and placed under house arrest at the Huainan University of Science and Technology in Shenzhen
Lovell-Badge said, CCR5 gene has been carefully studied in terms of it, it can protect us from HIV. But other effects of this gene variant on the body are not well known. Double mutations on CCR5 have also been associated with improved mental ability in mice and recovery after stroke in humans.
CCR5 works in the central nervous system, including the brain, so it can cause some neurological effects that we don't understand. A copy of the mutant may bring some benefits, Lovell-Badge said, or it may not be what it does in people of Northern European descent.
Africans and Asians are less likely to experience mutation delta-32, which raises the question: How could it ultimately affect two Chinese girls and another unpublished embryo? ?
Lovell-Badge says that embryo editing can get a place in science, but with our current understanding of genetics, this technique should only be used to prevent real diseases. It will cause inevitable consequences such as cystic fibrosis or sickle cell disease.
"I will also genetically modify [một phôi thai] if that in return has a clear clinical benefit", he told.
"In general, fixing a genetic defect to turn it back to normal is recommended. What He Jiankui did was not – he wanted to try to strengthen the babies to help them resist HIV. But in fact, he did something that everyone knows – harming the children. "