Explained: How Gene Editing Turned Hamsters Into Aggressive Beasts And What Are Ethical Concerns

A gene-editing experiment in hamsters turned them into aggressive creatures, altering their behaviour as well as gender-specific traits. 

The study at the Georgia State University in the United States removed one hormone from hamsters that governs their behaviour. The scientists expected it would reduce aggression and social communication, but it increased it.

While this altered behaviour in itself is interesting and leads to questions, the fact that hamsters have social organisation and some biological markers similar to humans makes it more interesting. 

Ethical questions have also surrounded gene-editing, as it involves altering the natural state of an organism. Here we explain the hamster study, what scientists understand from the unexpected results, and ethical questions surrounding gene editing. 

The hamsters' study, explained

Researchers at Georgia State University (GSU) used CRISPR-Cas9 gene-editing technology to remove 'Vasopressin' and the receptor that it acts on called 'Avpr1a' in hamsters. 

Vasopressin and Avpr1a receptor regulate social phenomena such as pair bonding, cooperation, social communication, dominance, and aggression in hamsters, said GSU in a statement. The results were opposite to what researchers expected.

Neuroscience Professor H Elliott Albers said, "We anticipated that if we eliminated vasopressin activity, we would reduce both aggression and social communication. But the opposite happened."

Instead, the hamsters without the receptor showed much higher levels of social communication behavior than did their counterparts with intact receptors, said GSU in a statement.

It added, "Even more interesting, the typical sex differences observed in aggressiveness were eliminated with both male and female hamsters displaying high levels of aggression towards other same-sex individuals."

The significance of study

The Syrian hamsters that were used in the study are similar to humans socially and in some biological indicators as well.

GSU Professor Kim Huhman said, "Their [hamsters'] stress response is more like that of humans than it is other rodents. They release the stress hormone cortisol, just as humans do.

"They also get many of the cancers that humans get. 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."

Albers added that the study on hamsters is important for human mental health applications.

He said, "Developing gene-edited hamsters was not easy. But it is important to understand the neurocircuitry involved in human social behavior and our model has translational relevance for human health.

"Understanding the role of vasopressin in behavior is necessary to help identify potential new and more effective treatment strategies for a diverse group of neuropsychiatric disorders ranging from autism to depression."

Ethical questions of gene-editing

While gene-editing has applications in medical science where it's used to correct genetic diseases and find treatments like GSU's Prof. Albers quoted above said, there are ethical questions over its probable applications in enhancing some biological features rather than treating medical conditions.

There are also fears of experiments leading to unforeseen results. While the hamsters' study was limited in extent and harmless to humans, a similar incident in a human trial can be disastrous.

Mary Todd Bergman highlighted the two types of gene-editing in The Harvard Gazette and noted how the implication of gene-editing in one person or a group might lead to results in future generation that might not be predicted at the time of editing.

She wrote, "While 'somatic gene-editing' affects only the patient being treated and only some of his or her cells, 'germline editing' affects all cells in an organism, including eggs and sperm, and so [the edited result] is passed on to future generations. The possible consequences of that are difficult to predict."

An article in Medical News Today notes the dual use dilemma, "Gene editing holds the key to preventing or treating debilitating genetic diseases, giving hope to millions of people around the world. Yet the same technology could unlock the path to designing our future children, enhancing their genome by selecting desirable traits such as height, eye color, and intelligence."

Several leading scientists have called for a moratorium on gene-editing until a consensus emerges on the subject.

CRISPR pioneer Feng Zhang of the Broad Institute of Harvard and MIT said, "The moratorium is a pause. Society needs to figure out if we all want to do this, if this is good for society, and that takes time. If we do, we need to have guidelines first so that the people who do this work can proceed in a responsible way, with the right oversight and quality controls."