Scientists Add Human Genes to Monkeys' Brains to Study Cognitive Evolution

In the monkey experiments, the researchers introduced the human MCPH1 copies into the rhesus monkey genome by injecting a virus containing the gene into monkey embryos. Some of the monkeys that were bred in this manner exhibited improved cognitive function.

The experiment, which was conducted at the Kunming Institute of Zoology and the Chinese Academy of Sciences with the help of US researchers at the University of North Carolina, involves inserting a human version of Microcephalin (MCPH1), a gene that is believed to play a role in the development of human brains, into the brains of 11 rhesus monkeys, according to AFP.

The Business Recorder, citing the government-controlled China Daily, reported a team of Chinese scientists found after lab experiments that rhesus macaques "got smarter and had superior memories as compared to the unaltered monkeys".

The monkeys' brains, though, did not grow bigger than the control group, and the test later drew ethical concerns and comparison to the famous Hollywood movie franchise "Planet of the Apes".

They said the study was meant to aid research into human psychological problems.

Styner's co-authors, however, said the traditional mouse or rat models were "less ideal" than monkeys because of the vast dissimilarities in brain size and structure between humans and rodents.

The monkey's brains developed along the same timeline as a human brain.

In doing this they created "transgenic monkeys".

Eleven monkeys with the edited genome were born, but only five survived.

However, a new breed of super monkeys whose brains evolve just like human ones - slower but with faster reaction times and short-term memory - increases the chances of such experiments getting out of hand, therefore becoming more than just a popular cinematic ploy. 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.

Martin Styner of the University of North Carolina who's role in this experiment was limited to training students how to extract brain volume from MRI images says "There are a bunch of aspects of this study that you could not do in the United States, it raised issues about the type of research and whether the animals were properly cared for." .

Other voices in the scientific community, however, disagree. The scientists involved said it was the first time such an experiment has been used to understand "the genetic basis of human brain origin".

"The use of transgenic monkeys to study human genes linked to brain evolution is a very risky road to take", according to James Sikela of the University of Colorado.

"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". Critics argue that humans and macaque monkeys are different on many levels and that simply modifying a couple of genes offers little value.

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