In a study published in the journal Scientific Reports, an international team of researchers from Sweden and the United Kingdom assessed the ‘heritability of dog ownership’ in the Swedish Twin Registry, the largest twin cohort in the world. The results show that genetic variation ‘explains more than half of the variation in dog ownership,’ implying that the choice of getting a dog is influenced by the genetic makeup of an individual.
“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 remains an enigma,” said Uppsala University’s Professor Tove Fall and colleagues.
“Dogs were the first domesticated animal and have had a close relationship with humans for at least 15,000 years. Today, they are common pets in our society and have been linked to increased well-being and improved health outcomes in their owners.”
“A dog in the family during childhood is associated with ownership in adult life. The underlying factors behind this association could be related to experiences or to genetic influences.”
“We aimed to investigate the heritability of dog ownership in a large twin sample including all twins in the Swedish Twin Registry born between 1926 and 1996 and alive in 2006.”
The researchers analyzed data from 35,035 twin pairs from the Swedish Twin Registry.
“Studying twins is a well-known method for disentangling the influences of environment and genes on our biology and behavior,” they explained.
“Because identical twins share their entire genome, and non-identical twins 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 team 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.
“We were surprised to see that a person’s genetic make-up appears to be a significant influence in whether they own a dog,” Professor Fall said.
“As such, these findings have major implications in several different fields related to understanding dog-human interaction throughout history and in modern times.”
“These kind 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,” added Dr. Patrik Magnusson, of Karolinska Insitutet.
“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.”
“The study has major implications for understanding the deep and enigmatic history of dog domestication,” said University of Liverpool’s Dr. Keith Dobney.
“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,” added Dr. Carri Westgarth, also from the University of Liverpool.
Tove Fall et al. 2019. Evidence of large genetic influences on dog ownership in the Swedish Twin Registry has implications for understanding domestication and health associations. Scientific Reports 9, article number: 7554; doi: 10.1038/s41598-019-44083-9