Ethically Fraught Experiment Has Produced Monkeys With Added Human Brain Genes
In a bid 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's called MC HP 1, or microcephalin, and it's involved in regulating the foetal growth of the brain.
The addition does seem to have made the monkeys smarter. The transgenic animals' brains took longer to develop - more like those of human children - and they also exhibited better memory skills, and faster reaction times, compared to their unmodified peers.
"This was the first attempt to understand the evolution of human cognition using a transgenic monkey model," geneticist Bing Su of the Kunming Institute of Zoology told Technology Review.
Transgenic organisms are nothing new. The first was published in 1974, when Staphylococcus aureus genes were spliced into 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 human cognition genes, including altered microcephalin. But the researchers believe that this is the first time researchers have used transgenic monkeys to look into the genetic origins of the human brain.
It is, scientists say, an experiment with concerning ethical implications.
The team exposed the monkey embryos to a virus carrying human microcephalin. This generated 11 transgenic rhesus monkeys carrying the human gene, only five of whom actually survived.
"Our findings demonstrated that transgenic nonhuman primates (excluding ape species) have the potential to provide important - and potentially unique - insights into basic questions of what actually makes humans unique, as well as into disorders and clinically relevant phenotypes," the researchers wrote in their paper.
But not everyone agrees. In fact, a 2010 paper expressly condemns the entire concept of editing apes with human brain genes (although not necessarily monkeys), calling such potential studies "ethically unacceptable" due to the elevated risk of harm to the animals.