An international team of scientists has sequenced 70 complete mitochondrial genomes from archaeological and modern dogs, spanning Central Mexico to Central Chile and Argentina. The research reveals that all pre-contact dogs in Central and South America descended from a single maternal lineage. This lineage diverged from North American dogs after humans first arrived on the continent.
Dr. Aurélie Manin of the School of Archaeology highlighted the significance of this finding: "This study reinforces the important role of early agrarian societies in the spread of dogs worldwide. In the Americas, we show that their spread was slow enough to allow the dogs to structure genetically between north, central and south America. It is rather uncommon for domestic animals and it opens new research avenues on the relationship that existed between dogs and these early agrarian societies."
The study indicates that instead of dispersing rapidly, dogs followed a slower path termed 'isolation by distance'. They gradually adapted to new environments as they moved with people through the Americas between 7,000 and 5,000 years ago. This movement coincided with the spread of maize cultivation by early farming communities.
The arrival of Europeans introduced new dog lineages which largely replaced indigenous ones. However, some modern Chihuahuas still carry maternal DNA from their pre-contact Mesoamerican ancestors. These genetic traces highlight an enduring legacy of America's first dogs and underscore the deep roots of this iconic breed.
Published in Proceedings of the Royal Society B under the title ‘Ancient dog mitogenomes support the dual dispersal of dogs and agriculture into South America’, this study adds a new chapter to the shared history between humans and dogs—a history marked by movement, survival, and companionship across continents.