In an attempt to learn more about the way the human brain develops, scientists in China have added a human brain gene to the genome of rhesus monkeys. It is called MC HP 1, or microcephalin, and is involved in the regulation of fetal brain growth.
The addition seems to have made the monkeys more intelligent. The brains of transgenic animals took longer to develop, more like those of human children, and they also showed better memory skills and faster reaction times, compared to their unmodified partners.
"This was the first attempt to understand the evolution of human cognition using a transgenic monkey model," said geneticist Bing Su of the Kunming Institute of Zoology at Technology Review.
Transgenic organisms are nothing new. The first was published in 1974, when Staphylococcus aureus genes were spliced in Escherichia coli. The first transgenic monkey, inserted with jellyfish genes, was created in 2001.
Human genes have been added to monkeys to study diseases and conditions such as autism, and mice have been modified with genes from human cognition, including altered microcephaline. But researchers believe that this is the first time that researchers use transgenic monkeys to investigate the genetic origins of the human brain.
It is, say the scientists, an experiment with relevant ethical implications.
The team exposed the embryos of monkeys to a virus that carried human microcephaly. This generated 11 transgenic rhesus monkeys that carried the human gene, only five of which survived.
"Our findings demonstrated that non-human transgenic primates (excluding ape species) have the potential to provide important, and potentially unique, information on basic questions of what really makes humans unique, as well as disorders and phenotypes clinically relevant, "the researchers wrote in their paper
But not everyone agrees. In fact, a 2010 article expressly condemns the whole concept of editing monkeys with genes from the human brain (although not necessarily monkeys), calling such studies potential as "ethically unacceptable" because of the high risk of harm to animals.
But wearing monkeys could be a step down that path.
"The use of transgenic monkeys to study human genes linked to the evolution of the brain is a very risky path," said geneticist James Sikela of the University of Colorado, who co-authored that 2010 article, to Technology Review.
"It's a clbadic problem with a slippery slope and one that we can expect to repeat as this type of research is done."
In addition, one of the researchers of the latter study, the computer scientist Martin Styner of the University of North Carolina, noted that there were aspects of the study that would not be allowed in a country with stricter regulations, such as the US. UU In fact, the research could not find a publisher in the West.
Chinese genetic research is already being pushed aside after the work of geneticist He Jiankui, who claimed to have edited the germline of human twins. His American collaborator, Michael Deem, from Rice University, has also been attacked.
It is difficult to know if Su's new investigation would receive the same reception if it were not under Jiankui's shadow, but the geneticist is not holding it back. He is already at work making new transgenic monkeys.
But Styner said he was considering removing his name from the newspaper.
"Now we have created this animal that is different from what it is supposed to be.When we do experiments, we must understand well what we are trying to learn, help society, and that is not the case here." he said.
"They're trying to understand brain development, and I do not think they're doing it."
The research has been published in. National Science Review.