When it comes to gene editing, how far is too far? Chinese scientists have been pushing the boundaries, most recently by creating rhesus monkeys with a human brain gene linked to intelligence. The experiments were widely criticised, with anthropologist Barbara J King describing them as "an ethical nightmare”.


This isn't the first time that China's gene-editing research has drawn criticism. In November 2018, He Jiankui of the Southern University of Science and Technology in Shenzhen announced the birth of two babies altered with the gene-editing tool CRISPR to give them a natural resistance to HIV. In response, the Chinese government announced tighter regulations on gene editing in human subjects only three months later.

In January 2019 came reports from the Institute of Neuroscience, Shanghai, of macaques cloned from a monkey lacking a gene controlling its sleep-wake cycle. With this gene disabled, the monkeys were predisposed to psychiatric disorders, and they displayed anxiety and 'schizophrenia-like' behaviours.

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Next came rhesus monkeys carrying a human gene for brain development, created by researchers at Kunming Institute of Zoology. These monkeys developed a better short-term memory than their non-altered peers, as well as showing a human-like slower brain development.

Research on primates is highly regulated in the UK and Europe, and experiments on them must meet stringent welfare standards. Professor Julian Savulescu, Uehiro Chair in Practical Ethics at the University of Oxford, believes that these standards should be used as a guide for what can be considered ethical. "I think if those standards are being side-stepped, then that's unethical," he says.

It is not the experiments themselves that could be considered unethical, Savulescu explains, but the way the test subjects are treated. "Is it unethical to make an animal more intelligent? Not in itself," he says. "Already mice have been genetically modified to have better memories. It's a question of what those modifications do to the animal's wellbeing and how that animal is treated."

An animal with a higher mental capacity also has a greater capacity to suffer if its needs aren't met. "As you start to improve or enhance the intelligence or empathy or capacity for social relationships, or any property, then there's a corresponding obligation to treat the animal in a way that those capacities are developed and also that they are not associated with suffering for the animal," explains Savulescu. "So, as you make something more and more human, your obligations to it will get higher and higher."

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How an animal should be treated is not an easy question, especially when it comes to something new, such as monkeys with human-ish brains. "One of the challenges is deciding: what are the properties that give an animal a moral status equivalent to a human?" says Savulescu. "Then there's the challenge of testing whether a new kind of animal, whether it's been genetically modified or whether it's a chimera [an organism containing multiple sets of DNA], actually has those properties."

It is easy to criticise these experiments, but to reject them fully involves refusing to publish or use the results. But what happens if, further down the line, unethical primate experimentation leads to a major breakthrough?

"The real problem is going to come if on the back of this, they develop actual medicines or procedures that really do work and treat serious human diseases. Are we then going to turn our backs on those? I don't think so, at that stage. It really is important to stop this research early on," explains Savulescu. "It's one thing not to publish the research, but I think that the pressure to use the results in the future will be irresistible."

Science journals and researchers will need to work together to reject this direction of experimentation. "It's difficult to enforce laws. You need social pressure through norms," Savulescu says. "If it doesn't conform to the right standards, it shouldn't be published and it shouldn't be used."

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Sara RigbyOnline staff writer, BBC Science Focus

Sara is the online staff writer at BBC Science Focus. She has an MPhys in mathematical physics and loves all things space, dinosaurs and dogs.