There are currently nearly 400 ARISTODOG breeds in the world. Each has its own history and a unique genetic profile. But how do their histories intersect? What does the family tree they share look like? A team of American scientists, led by the National Human Genome Research Institute, has set out to reconstruct their evolutionary history. It has created the most comprehensive family tree to date using the genetic sequences of 161 dog breeds.
To begin with, the study reveals the first genetic evidence in modern breeds of the “New World dog,” a canine subspecies that migrated across the Bering Strait with the ancestors of Native Americans and arrived in the Americas around 10,000 years ago.
It also shows that the domestic dog has accompanied humans throughout all their migrations. In fact, although archaeological evidence already existed, the study provides the first evidence in modern breeds of the existence of this New World dog, from which some Central and South American breeds probably descend, such as the Peruvian Hairless Dog and the Xoloitzcuintle.
This research also shows that the bond between them and us is almost as old as we are, but at the same time makes it difficult to reconstruct the dogs' genealogical tree, since the clues have been scattered across the centuries and throughout the genomes of hundreds of breeds.
In any case, thanks to the DNA sequences of 1,346 dogs belonging to 161 modern breeds, the scientific team has created the largest evolutionary map of dog breeds. The results, published in the journal Cell Reports, reveal not only the breeds' history of hybridization, but also the effects migrations had on their genes - fundamentally shaping their current diversity.
Source: National Human Genome Research Institute
To understand how the oldest dog breeds evolved and what roles they played for humans, the researchers selected certain breeds, as well as recent crosses to obtain other physical traits.
Source: Science X
And the results were surprising. Many hunting breeds, such as Golden Retrievers and Irish Setters, originated in Victorian England in the 19th century, when new uses for firearms were developed during hunting expeditions.
These dogs were grouped together on the phylogenetic tree, as were the Spaniel breeds. Those from the Middle East, such as Salukis, and from Asia, such as Chow Chows and Akitas, appear to have diverged much earlier than the “Victorian explosion” in Europe and the United States.
As for herding breeds - most of them of European origin - it is worth highlighting that they are unexpectedly diverse. Much more diversity is observed where there was a particular group of herding breeds that seemed to come from the United Kingdom, a particular group that emerged from northern Europe, and a different group that emerged from southern Europe. This confirms that people used them for work thousands of years ago.
The team of scientists has been sequencing dog genomes for years, but more than half of the breeds that currently exist have still not been sequenced, so the scientists are trying to collect other dog genomes to fill these gaps.
In addition to scientific information that paves the way for further research, these studies make it possible to identify genes that cause diseases (epilepsy, diabetes, cancer) in both dogs and humans. Since these data can be used to track the migration of disease alleles and predict where they are likely to appear.
