Where ever humans have gone, so have dogs – a mutualistic relationship that has left co-evolutionary traces in their brains, behavior, and bodies. However, despite dogs’ ubiquity in human societies, keeping dogs is not a universal trait among individuals. Is the predilection for canine company purely an acquired taste, or might dog-keeping also be written in the genes?

According to a recent study, maybe there's something in your chromosomes. Genes wield significant influence over whether someone is a “dog person,” with over half of variation in dog ownership explainable by heredity (which means the other half of explaining why someone does or does not have dogs is explained by something else).

The authors relied on powerful data sets to analyze dog ownership in 35,035 twin pairs: the Swedish Twin Registry (the largest twin cohort database in the world) and dog registration records from the Swedish Board of Agriculture and Swedish Kennel club (estimated to account for 83% of the country’s dogs, due to national laws requiring their registration).

This study is the first to suggest that dog ownership has a notable genetic component, heritable by 57% for females and 51% for males. Identical twins were found to be more likely to own dogs than non-identical twins – offering evidence that genetic factors play a role in that choice, since identical twins share their entire genome and non-identical twins share only half.

To be clear, this is pure correlation. No responsible “dog owning” gene has been isolated, but these findings tap into the biggest questions surrounding domestication: not just how, but why, did it happen? A genetic component offers new pathways for probing these layers.