Fonni’s Dog: Tracing an ancient migration with pets in tow

A genomic analysis of 28 dog breeds has traced the genetic history of the Fonni’s Dog, a herd guardian endemic to the Mediterranean island of Sardinia.

The study revealed that the origins of the Fonni’s Dog mirror human migration to Sardinia.

Past studies of the island’s human inhabitants have shown they share greatest genetic similarity with people from Hungary, Egypt, Israel and Jordan.

“The map we can draw of the dog’s origins is the same as the map of human migration to Sardinia,” says study leader Elaine Ostrander of the National Human Genome Research Institute. “Clearly ancient people traveled with their dogs, just as people do now.”

The close parallels between the history of the dog and human inhabitants of the island has a practical implication, says Ostrander. “Our study shows how closely dog migration parallels human migration. It could be that if you have missing pieces in a study of a human population’s history, samples collected from dogs in the right place could fill in those gaps.”

Geneticists’ delight

The island home of the Fonni’s Dog has long held the interest of geneticists.

Because Sardinia is geographically isolated, its human inhabitants share a unique ancestry and relatively low genetic diversity. Those characteristics make it easier to study genetic influences on disease and aging in Sardinians than in other human groups.

Ostrander and other canine geneticists argue that each of the hundreds of different dog breeds also represent isolated populations that could be harnessed for genetic studies.

“Dogs get all the same diseases as humans and there are lots of dog breeds with genetic predispositions, for example to particular types of cancer,” Ostrander says. “Once we understand the genetic history of a breed, we can search for disease genes in a much more powerful way than is possible in humans, enabling us to hone in on medically relevant genes.”

‘Outstanding thieves’

Fonni’s Dogs are large, rugged dogs known for their wariness toward strangers and their intense facial expression.

“If you were to look at 10 Fonni’s Dogs, you would see there’s a lot of variation in coat color and fur length. But they are all good protectors of their flocks. That’s because nobody cares what they look like; they’ve been bred to do a job and to do it right,” says Ostrander.

That job is guarding the possessions of their owner, to whom they are fiercely loyal.

“Fonni’s are also outstanding thieves,” says Ostrander. “They can be trained to sneak over to the neighbors’ and bring items home.”

While this particular duty isn’t required of today’s Fonni’s Dogs, written records from the mid-1800s indicate thievery was part of their historical repertoire.

Truly a breed

The results of the genomic study, published in the journal GENETICS, reveal a regional variety that has developed into a true breed through unregulated selection for its distinctive behavior.

To better understand how the Fonni’s Dog developed, scientists from the NHGRI, the University of Milan and G. d’Annunzio University analyzed blood samples from dogs living in different parts of Sardinia. They sequenced the whole genome of one of these dogs.

To trace the Fonni’s relationship to dogs from around the Mediterranean, the team compared the data to DNA from 27 other European, Middle Eastern and North African breeds.

The data revealed that the Fonni’s Dog shows all the genetic hallmarks of being a breed, even though it developed in the absence of a regulated pedigree program and only arose through the tendency of Sardinian shepherds to choose their best guard dogs for breeding.

The researchers compared individual dogs from within the same breed and across different breeds, quantifying many aspects of genome variation and genetic distinctiveness. All these measures confirmed that the Fonni’s Dog, in genetic terms, is a breed.

Still, the dog is not officially recognized as a breed by most international registries, including the largest federation of kennel clubs, the Federation Cynologique Internationale.

The study also revealed the ancestors of the Fonni’s Dog were related to the Saluki, a swift and graceful “sight” hound from the Near and Middle East and a large mastiff like the Komondor, a powerfully-built sheep guardian from Hungary that looks a bit like a mop.

The team plans next to study in greater detail 11 regions of the genome that likely make the Fonni’s Dog distinct — regions that may be responsible for their characteristically loyal and protective behavior.

Ostrander points out the study was a collaborative effort with scientists from Italy, including Sardinia, and says she is gratified to find so many researchers across the world interested in similar questions.

Her group is hoping to work with colleagues in a range of countries to explore other so-called “niche” dog populations, regional varieties that often have a history of being bred for a particular job. Their goals are to better understand how dogs have evolved and to demonstrate yet another important job for these faithful human companions: tracking down disease genes.