Study shows monkey's emotions linked to genes

A new study on rhesus macaques has revealed a link between the monkeys’ genetics and their social attention and behaviour.

Primatologists and animal welfare scientists from Liverpool John Moores University, the University of Chester and the Medical Research Council, found that genetic variants associated with serotonin, dopamine and oxytocin influence macaque social attention and fear and anxiety behaviours.

Their results, published in PLOS ONE, suggest that these previously unstudied genetic variants may explain some of the biological underpinnings of individual variation in negative emotion and social behaviour.

Lead author, Dr Emmeline Howarth, who completed her PhD at LJMU and now works at the University of Chester, said “our findings have the potential for use in managing both wild and captive primate populations and may have some translational value for understanding the evolution and function of negative emotions in our own species too”.

“Understanding the causes, consequences and expression of negative emotions is essential for good welfare. If we can determine which macaques are more likely to react badly to stressors and experience fear and anxiety, we can provide for them better in captivity and properly assess whether they are suitable to be included in breeding programmes.”

Using data from 109 rhesus macaques, the team assessed the relationship between social attention, key behaviours for survival, and variation in eight genes involved in emotion. Five variants studied had not previously been studied in primates and four have not been studied in either humans or other primates.

The previously unexamined variants in the dopamine and oxytocin pathways were found to be correlated with social attention, which was measured using attention bias to threat. Attention bias is a non-invasive method of welfare assessment that uses looking patterns to social stimuli to evaluate emotion. The method was adapted from the human literature for monkeys by Dr Emily Bethell, an Associate Professor in Primate Cognition and Behaviour at LJMU and senior author of the study.

Rhesus macaques are the most commonly used primate species in biomedical research so developing methods of welfare assessment for these animals has the potential to positively impact thousands of animals. The research was partially funded by the National Centre for the Replacement, Refinement and Reduction of Animals in Research, which is committed to improving animal welfare in research settings.

The team highlighted that future work on emotional behaviour in macaques should focus particularly on four key variants identified in the current research: HTR2A (5-hydroxytryptamine receptor 2A), DRD4 (Dopamine Receptor D4), OXTR (Oxytocin receptor) and AVPR1a (Arginine vasopressin receptor 1A). “Prior to this work we knew nothing about the influence of these key genes on social attention and behaviour in macaques,” said Dr Emmeline Howarth. “I am excited to see what future work in this area reveals and the positive impact it has on primate welfare.”