Scientists Slammed For Putting Human Brain Genes In Monkeys

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The idea of monkeys containing human intelligence used to be the realm of science fiction, like in the Planet of the Apes films. However, scientists in China have recently been slammed for trying to make that fiction a reality by putting human brain genes in monkeys, according to The Scientist.

On March 27, researchers from Kunming Institute of Zoology, Chinese Academy of Sciences, and the University of North Carolina published a report in National Science Review that claimed they had successfully edited monkey rhesus DNA to contain a human gene.

The specific gene inserted into the monkeys was microcephalin, also known as MCPH1. This gene is specific for humans because it affects brain size during fetal development. Humans are unique in that their brains take much longer to develop compared to primates. in a process called neoteny, which leads to higher levels of intelligence. While most primates’ brain development ends after birth, human brains continue to grow in infancy and beyond, due to neural plasticity.

The scientists exposed the monkey embryos to viruses containing MCPH1 so that monkeys would similarly undergo neoteny. As a result, the monkeys showed “human-like brain development” and increases in short term memory.

However, many scientists are slamming the experiment as a gross ethics violation, claiming that it was “reckless.” James Sikela of the University of Colorado vocalized his strong misgivings in MIT’s Technology Review.

“The use of transgenic monkeys to study human genes linked to brain evolution is a very risky road to take. It is a classic slippery slope issue and one that we can expect to recur as this type of research is pursued.”

Even researchers associated with the experiment, like Jacqueline Glover, a University of Colorado bioethicist, admit that the study was in the wrong.

“You just go to the Planet of the Apes immediately in the popular imagination… To humanize them is to cause harm,” she said. “Where would they live and what would they do? Do not create a being that can’t have a meaningful life in any context.”

However, the head researcher of the experiment, Bing Su, does not believe there is an ethical issue.

“Although their genome is close to ours, there are also tens of millions of differences,” he said in an email.

Su also acknowledged that he would not do the experiment on apes, as he believed their genome was much closer to humans than that of the rhesus monkeys.

monkey looking at hand
Featured image credit: Vishu Gowda Unsplash

Despite the controversy, Su is continuing his experiments, and is now focusing on SRGAP2C, a DNA variant that has been named “the humanity switch.”