Scientists in China have inserted a human gene that plays an important role in our brain’s development into the genome of macaque monkeys. Some of the monkeys that were bred in this manner exhibited improved cognitive function. However, the international community has condemned the experiment as unethical.

Credit: Pixabay.

The research led by scientists at the Kunming Institute of Zoology in southwestern China involved inserting human copies of the MCPH1 gene into monkey embryos via a virus that carried the gene. A total of 11 transgenic macaque monkey embryos were generated, out of which only five survived. These surviving monkeys were put through a barrage of cognitive tests, including memory tests and brain scans. The results suggest that the macaques performed better on short-term memory tasks than their unmodified peers and their brains developed over a longer period of time, which is typical of human development.

According to the researchers, the aim of the study is to probe the fundamental biology that enabled humans to develop our unique brand of intelligence. So, naturally, the Chinese authors decided to zero-in on a gene that is involved in brain size and cognitive abilities. In the future, similar research might enable scientists to develop treatments for diseases caused by abnormal brain development. For instance, over the years, Chinese researchers have engineered monkeys that show signs of Parkinson’s, Duchenne muscular dystrophy, autism, and more.

Another gene that may be soon be added inside the monkeys of genomes in subsequent experiments is FOXP2, which is widely believed to be integral to our language abilities. Then there’s SRGAP2C, a gene variant that first appeared around two million years ago as one of our ancestors, Australopithecus, was losing ground in Africa to early humans. This gene is also called “humanity’s switch” due to its alleged role in the emergence of human intelligence.

While such scientific inquiries definitely have their merit, their ethics are controversial. Su Bing, from the Chinese Academy of Sciences’ Kunming Institute of Zoology and lead researcher of the new study, says that the experiments were validated by the institution’s ethics board and followed Chinese and international best practices.

Other voices in the scientific community, however, disagree. Critics believe that transgenic experiments on monkeys and apes puts us on a slippery slope where it becomes difficult to draw the line of what is acceptable and what is not. One such critic is University of Colorado geneticist James Sikela who wrote a 2010 paper arguing that transgenic experimentation on primates raises a number of ethical problems, as well as physical harm.

“Transgenic apes, our closest evolutionary relative, have the highest potential to express human lineage specific (HLS) sequences as they are expressed in Homo sapiens and likewise experience harm from such transgenic research. These harms render the conduct of this research ethically unacceptable in apes, justifying regulatory barriers between these species and all other non-human primates for transgenic research,” Sikela and colleagues wrote at the time.

Animals are regularly inflicted with various diseases so that scientists can then experiment on them to find new treatments and drugs. Changing an animal’s genome, however, is completely different in the sense that it can alter its fundamental biology. Critics argue that humans and macaque monkeys are different on many levels and that simply modifying a couple of genes offers little value. For instance, this study’s small sample size means that researchers can’t conclude with confidence that the introduced gene variant made the animals smarter, nor does the study tell us anything new about the MCPH1 gene.

Writing for MIT Technology Review, University of Colorado bioethicist Jacqueline Glover compared the new study from China to something out of the Planet of the Apes, a movie where enhanced primates overthrow humans.

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

This is just the most recent research out of a string of controversies stemming out of Chinese labs. Last year, He Jiankui and colleagues at the Southern University of Science and Technology, in Shenzhen, shocked the world after announcing the first gene-edited babies. In the future, we’ll likely be surprised by even more outlandish findings.