Scientists Create a Dog Breed “Family Tree”

At first glance, a new visual representation of the canine family tree looks more like a pinwheel than a maple, but the researchers who recently mapped out a genetic history of over 160 dog breeds (published in the journal Cell Reports) have provided us with fascinating new insights into the evolution of dog breeds and how they are related to each other…and human history.

A study was conducted on the genetic data of 1,346 dogs representing 161 different breeds from all over the world.  The researchers discovered that while many breeds are interconnected, there are also some interesting outliers that have few connections with other breeds.  The connections between breeds can happen by chance, with human migrants who bring their dogs with them to other parts of the world, or through direct human intervention via cross-breeding.

As an example, the researchers highlight genetic variation among three breeds in the study (the Tibetan Mastiff, Saluki, and Cane Corso).  DNA collected from populations of these dogs in the US was quite different than DNA collected from the breeds in their countries of origin.  For example, American Cane Corso dogs show much more evidence of intermixing with other breeds (Mastiffs and Rottweilers) than those in their country of origin, Italy.

What are some other interesting findings of the study?

The researchers were able to confirm historical accounts of our creation of bull terrier breeds (for the purpose of dog fighting) through genetics.  All bull and terrier crosses can be mapped to the terriers of Ireland during the years 1860-1870, according to the study.

Speculation that the domestication of dogs first occurred in Central and East Asia is confirmed by genetic testing that identifies Asian spitz-type dogs as among the very earliest breeds.

Dogs traveled from Asia to the Americas 10,000 years ago with the first human migrants.  But the original New World dogs, like the distinctive Xoloitzcuintle, eventually encountered the dogs brought to the Americas by later European migrants and extensively interbred with them, especially herding breeds.

The authors point to two breed types—sighthounds and livestock guardian dogs—as examples of how breeds can develop in different geographic regions (the UK and the Mediterranean in this case) and share similar characteristics but not the same genetic material.  So a trait like speed or large size can be developed in isolation, but the resulting dog can be similar to unrelated dogs from other areas.

Interested in learning more?  You can read the full text and see more illustrations HERE.