Gene edited hamsters turned into aggressive bullies in unexpected lab twist

Sometimes experiments don’t go as planned. Case in point: when some scientists set out on making hamsters more “peaceful” via gene editing, they accidentally made the fuzzy little rodents more aggressive instead. And synthetic biologists and animal gene tweakers everywhere should sit up, take note, and think of this as a cautionary tale of what happens when fuzzy animals meet cutting edge sci-fi like technology.

Neuroscientists at Georgia State University (GSU) wanted to see how vasopressin, a mammalian hormone, influenced social behaviour. They used a relatively novel technology called CRISPR-Cas9 - which allows scientists to edit organisms’ genomes - to suppress a vasopressin receptor in Syrian hamsters. The expectation was that preventing the hamsters’ bodies from utilizing vasopressin would result in calmer, more peaceful behavior - but the result was anything but.

Instead, cutting vasopressin out of the hamsters’ system resulted in “high levels of aggression,” particularly toward hamsters of the same sex. Though “normal” male hamsters are notoriously more aggressive than female ones, the startling change occurred in both sexes.

Previous studies have suggested that more - not less - vasopressin correlates with higher levels of cooperability. In 2016, researchers at the California Institute of Technology, Pasadena found that administration of vasopressin in humans resulted in an increased tendency to “engage in mutually beneficial cooperation.” This aligns with even earlier research, which showed that vasopressin may be responsible for regulating social behaviors related to sexual expression and aggression.

“This suggests a startling conclusion,” said H. Elliott Albers, a neuroscience professor and the leader of the study, in a GSU statement. “Even though we know that vasopressin increases social behaviors by acting within a number of brain regions, it is possible that the more global effects of the Avpr1a receptor are inhibitory. We don’t understand this system as well as we thought we did.”

Syrian hamsters are ideal test subjects for a number of research purposes, including those targeting social behavior, cancer, and even COVID-19.

“Their stress response is more like that of humans than other rodents. They release the stress hormone cortisol, just as humans do. They also get many of the cancers that humans get,” said Professor Kim Huhman, Associate Director of the Neuroscience Institute at GSU. “Their susceptibility to the SARS-CoV-2 virus that causes COVID-19 makes them the rodent species of choice because they are vulnerable to it just as we are.”

GSU’s Neuroscience Institute and similar establishments intend to continue investigating the effects of suppressed or increased vasopressin in mammals. As the related body of research grows, so might treatments for depression and other mental illnesses.