How far should we go with gene editing in the search for the “perfect” human being?

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The name He Jiankui is not listed as a registered delegate to the Third International Summit on Human Genome Editing, which will be held at the Francis Crick Institute in London next month. However, the disgraced Chinese scientist will be on the minds of most attendees. He will be a ghost at the science party.

Jiankui was responsible for one of the most controversial acts in modern scientific history, as revealed at the previous global genome editing summit, held in Hong Kong in 2018. In front of stunned delegates, the researcher, then working at the South China University of Science and Technology in Shenzhen, announced that it had changed the genetic makeup of three girls in an attempt to make them resistant to HIV. This modification, made when they were embryos, could then be passed on to future generations.

The experiment is unprecedented in modern genetics and was considered unethical by Chinese authorities. Jiankui was subsequently jailed for three years, although his influence on next month’s science summit will remain profound, said Professor Robin Lovell-Badge, organizer of the forthcoming London summit.

“We will discuss what happened to the three children whose physiology he may have altered through genome editing,” said Lovell-Badge, who also chaired the session where Jiankui revealed his extraordinary biological intervention. “We will also have presentations on the changes that have occurred in China in terms of the law and ethics governing gene editing. Clearly there have been quite substantial changes, for the better.

“And it’s important that these issues be raised. Genome editing has enormous power to benefit people, but we need to be transparent about how it is being tried and tested before the technology is put into practice.”

Genome editing was transformed by Jennifer Doudna of the University of California, Berkeley, and Emmanuelle Charpentier, of the Max Planck Institute for Infection Biology, in Berlin. Their research was rewarded in 2020 when the pair received the Nobel Prize in chemistry for creating “a technology [that] has revolutionized the molecular sciences of life”, in the words of the Royal Swedish Academy of Sciences, which made the award.

The technique developed by Doudna and Charpentier is known as Crispr-Cas9, and it acts like a pair of molecular scissors that can cut a strand of DNA at a specific site. In this way, scientists can alter the structure of genes in plants, animals and humans, and in turn induce changes in physical traits such as eye color and disease risk. It is not about introducing genes from other organisms, a crucial difference from previous forms of genetic manipulation.

Scientists are now looking at genome editing to develop new medical treatments, for example, making changes to people with diseases. Candidates include the inherited disease sickle cell anemia, in which a single genetic defect disrupts hemoglobin production with dire consequences for patients, who suffer from anemia because their bodies starve of oxygen.

American biochemist Jennifer Doudna, left, and French microbiologist Emmanuelle Charpentier, who won the 2020 Nobel Prize in Chemistry for developing a genome-editing method similar to “molecular scissors.” Photo: Alexander Heinl/AP

By removing a person’s stem cells and then genetically editing them to start producing fetal hemoglobin, a process that is normally interrupted at birth, red blood cells can be restored to their bodies, scientists believe. Trials are already underway at several centers.

In addition, doctors and researchers are investigating ways to use genome editing to address muscular dystrophy, cancer, diabetes, some forms of hereditary blindness, and many other debilitating conditions that have defied previous attempts to cure them. At next month’s summit, hundreds of delegates will gather to hear the latest developments.

Other experts are looking even further into the future. One idea is to alter astronauts’ physiology so they are better protected against radiation and the effects of weightlessness, invaluable for travel to Mars and beyond.

“You could also think about modifying liver enzymes so that men and women can better get rid of toxins used in chemical warfare, or to make changes that make them more resistant to biological weapons,” Lovell-Badge added. “That’s the kind of human enhancement that military researchers are thinking about right now.

“You could also contemplate altering humans so that they could see in the infrared or ultraviolet range, as some animals can. These upgrades would be ideal for troops fighting at night or in other hostile conditions.”

To what extent society will tolerate such human enhancements is a different matter, one to be addressed at a separate event at the Francis Crick Institute. A public exhibition, titled Cut + Paste, will explore what changes can be safely made in humans using genome-editing technology; which ones should qualify as priorities and which ones might be considered morally unacceptable and excluded from further exploration.

“Genome-editing tools offer enormous potential to improve human health and the world around us, but like all new technologies, they raise ethical questions and concerns,” said Ruth Garde, curator of Cut + Paste, which opens this week. “The public doesn’t know much about these techniques today. Cut + Paste will allow visitors to explore and reflect on the ethics of genome editing through a series of interactive experiences.”

The exhibition will cover all aspects of genome editing, including its use to improve crops and farm animals, although its impact on humans will be the main focus, as will be the case at next month’s international summit. “Genome editing has made it easier to imagine ‘enhanced’ human traits,” Garde added. “Cut + Paste asks visitors to ask themselves what does ‘improvement’ mean? What is a ‘desirable’ trait? And who decides that?

Visitors will be asked to consider a variety of uses for genome editing: to tackle diseases like malaria by using technology to render mosquitoes infertile; improve human capabilities; and make physiological changes that will be passed down from generation to generation. “Most importantly, we invite visitors to tell us what they think of these ideas,” Garde said.

Chinese scientist He Jiankui speaks at the Second International Summit on Human Genome Editing in Hong Kong in 2018.

Chinese scientist He Jiankui speaks at the Second International Summit on Human Genome Editing in Hong Kong in 2018. Photograph: Anthony Wallace/AFP/Getty Images

These issues will also be intensively discussed at the summit. “Genome editing for sickle cell disease has great potential, but it’s also very expensive,” Lovell-Badge said. “A treatment for one person could cost a million dollars. However, the disease is more prevalent in Africa, where people can afford less expensive drugs. So are we in danger of creating even greater health gaps between developed and developing nations? It’s a key concern.”

The dishonest activities of Jiankui, who has since said he acted “too quickly”, will bring an additional chill to the discussions. “Jiankui is now out of jail and running a lab again in Beijing,” Lovell-Badge said. “He says that he is going to focus on gene therapy to treat diseases such as muscular dystrophy. And that scares me because he is not a biologist. He knows little about the disease.

As for the motivation for Jiankui’s past actions, the scientist has since pointed to the fact that HIV infection can lead to people being ostracized. He wanted to get around that. “He chose to try to make changes to the CCR5 gene which has natural variants that can protect against HIV. In this way, he hoped to create gene-edited protection,” Lovell-Badge said.

“But experiments have also shown that in about 20% of cases, these genome editing changes can lead to substantial rearrangements of a person’s genome, which is very, very dangerous. It could cause cancer. This shows why it is so important that we carefully pursue this technology.”

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