Despite lacking large teeth, claws, or a heavy fur coat to survive in the cold, human beings have managed to rely on their large brains and creativity to become the dominant species on nearly every land mass on Earth. Now, Chinese scientists and researchers have successfully implanted genes from the human brain into monkeys, producing a measurable increase in their apparent intelligence, raising a number of questions about the ethical implications of such work.

In the 1920s, the Soviet Union devoted funds and resources to cross-breeding humans with anthropoid apes in an ill-fated experiment that some contend was aimed at developing super soldiers with human intellect and ape-like physical abilities. While the experiment itself has been proven to exist, there remains debate about the actual goal of the endeavor, with anthropologist Eric Michael Johnson characterizing it instead as a “sordid tale of ethical misconduct.” Like the fictional scientists behind “Jurassic Park,” Johnson contends Soviet scientists were so wrapped up in finding out if they could add human intellect to our ape cousins, no one stopped to question whether they should.

These recent Chinese experiments opted not to use humanity’s closely related apes for their experiments, seemingly for ethical reasons. Instead, they chose small monkeys that were on a more distant limb of the family tree. Monkeys are similar to human beings in many ways, but in far fewer ways than their ape cousins.

“Although their genome is close to ours, there are also tens of millions of differences,” explained Bing Su, the geneticist at the Kunming Institute of Zoology who led the effort. According to him, these monkeys lack the genetic capability to become anything more than monkeys through the introduction of human brain genes. It can, however, make them smarter.

According to the peer-reviewed study, the “transgenic” monkeys they created demonstrated a slightly delayed brain maturation like what’s commonly found in human offspring.

“More importantly, the transgenic monkeys exhibited better short-term memory and shorter reaction time compared to the wild type controls in the delayed matching to sample task,” the study reads.

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In order to accomplish this, the team at the Kunming Institute exposed the monkey embryos to a virus that carried human microcephalin genes. A total of 11 monkeys with the human genes in their brains were produced through the effort, with five surviving long enough to be subject to experimentation. Each surviving monkey carried between two and nine copies of the human gene.

Western scientists are highly critical of the endeavor, pointing out that five monkeys aren’t enough to produce any reasonable scientific conclusions and expressing their concerns over the questionable ethics. Among them was one scientist who’s actually listed as a co-author on the Chinese study.

“I don’t think that is a good direction,” says Martin Styner, a University of North Carolina computer scientist and specialist in MRI technology who assisted in the Chinese effort. “Now we have created this animal which is different from what it is supposed to be. When we do experiments, we have to have a good understanding of what we are trying to learn, to help society, and that is not the case here.”

Bing Su agrees with Styner’s view that the group of monkeys was too small to draw concrete conclusions. His solution, unsurprisingly, is to make more transgenic monkeys for further experimentation, an idea Styner finds troubling.

“There are a bunch of aspects of this study that you could not do in the U.S.,” says Styner. “It raised issues about the type of research and whether the animals were properly cared for.”