New research led by Dr Aurélie Manin traces the incredible journey of humankind’s best friend in the Americas

An international team of scientists has uncovered new clues about the incredible journey of dogs through the Americas — and how their story is deeply intertwined with human migration, agriculture, and cultural change.

Photo credit: Nicolas Goepfert

Analysis of archaeological and palaeogenomic data has already established that dogs were the first and only domesticated animals to accompany early humans into the Americas. What has remained unclear is when and how these canine companions reached Central and South America.

Now new research by an international team of scientists, led by Dr Aurelie Manin, sequenced 70 complete mitochondrial genomes from both ancient and modern dogs found from Central Mexico to Central Chile and Argentina. Their findings reveal a rich and complex history of dog populations in the Americas.

The study shows that all pre-contact dogs in Central and South America belong to a unique genetic lineage, one that split from North American dogs after their arrival on the continent. The timeline of this divergence closely matches the spread of agriculture and the rise of maize farming between 7,000 and 5,000 years ago, suggesting that dogs may have expanded southward alongside early mobile, farming communities.

A key finding of this study is that the spread of dogs followed a pattern known as isolation by distance, meaning dogs gradually moved further south with human groups, adapting to new environments over time.

After European contact, new dog lineages from Europe began to arrive, leaving their mark on today’s village dogs across the continent. Still, echoes of the ancient past remain: the study found that some modern Chihuahuas carry maternal ancestry that traces directly back to their pre-contact Mesoamerican roots.

Dr Manin says “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”.