Dogs were the first domesticated animal and, according to the archaeological evidence, have had a close relationship with humans for at least 15,000 years. The relationship between humans and dogs is the longest of all the domestic animals, yet the origin and history of perhaps our most iconic companion animal remain an enigma and a topic of much ongoing scientific debate.
Decades of archaeological and more recent genetic investigations across the world have so far failed to resolve the fundamental questions of where, when and why wolves formed the transformational partnership with humans that finally resulted in the first domestic dog.
Now, a new study by Uppsala University suggests that an individual’s genetic make-up has a great influence on whether they choose to acquire a dog. Genes appear to account for more than half of the difference in dog ownership.
In order to determine whether dog ownership has a heritable component, scientists compared the genetic make-up of twins (using the Swedish Twin Registry – the largest of its kind in the world) with dog ownership. Scientists found that a person’s genetic make-up appears to be a significant influence on whether they own a dog.
Tove Fall, lead author of the study, and Professor in Molecular Epidemiology at the Department of Medical Sciences and the Science for Life Laboratory, Uppsala University said, “As such, these findings have major implications in several different fields related to understanding dog-human interaction throughout history and in modern times. Although dogs and other pets are common household members across the globe, little is known how they impact our daily life and health. Perhaps some people have a higher innate propensity to care for a pet than others.”
Carri Westgarth, Lecturer in Human-Animal interaction at the University of Liverpool and co-author of the study, adds: “These findings are important as they suggest that supposed health benefits of owning a dog reported in some studies may be partly explained by different genetics of the people studied.”
Studying twins is a known strategy for unraveling the impacts of environment and genes on our biology and behavior. Since identical twins share their whole genome, and non-identical twins, all things considered on average share only half of the genetic variation, comparisons of the within-pair concordance of dog ownership between groups can reveal whether genetics play a role in owning a dog.
The researchers found concordance rates of dog ownership to be much larger in identical twins than in non-identical ones – supporting the view that genetics indeed plays a major role in the choice of owning a dog.
Patrik Magnusson, senior author of the study and Associate Professor in Epidemiology at the Department of Medical Epidemiology and Biostatistics at Karolinska Insitutet, Sweden said, “These kinds of twin studies cannot tell us exactly which genes are involved, but at least demonstrate for the first time that genetics and environment play about equal roles in determining dog ownership. The next obvious step is to try to identify which genetic variants affect this choice and how they relate to personality traits and other factors such as allergy.”
Zooarchaeologist and co-author of the study Keith Dobney, Chair of Human Palaeoecology in the Department of Archaeology, Classics and Egyptology at the University of Liverpool said, “The study has major implications for understanding the deep and enigmatic history of dog domestication. Decades of archaeological research have helped us construct a better picture of where and when dogs entered into the human world, but modern and ancient genetic data are now allowing us to directly explore why and how?”
The study is published in the journal Scientific Reports.