New genetic research shows extent of cross-breeding between wild wolves and domestic dogs

Date:  March 21, 2018

Source:  University of Lincoln

Mating between domesticated dogs and wild wolves over hundreds of years has left a genetic mark on the wolf gene pool, new research has shown.

The international study showed that around 60 per cent of Eurasian grey wolf genomes carried small blocks of the DNA of domestic dogs, suggesting that wolves cross-bred with dogs in past generations.

The results suggest that wolf-dog hybridisation has been geographically widespread in Europe and Asia and has been occurring for centuries. The phenomenon is seen less frequently in wild wolf populations of North America.

Researchers examined DNA data from grey wolves -- the ancestors of the domestic dog -- to determine how much their gene pool was diluted with the DNA of domestic canines, and how widespread the process of hybridisation is.

Despite the evidence of hybridisation among Eurasian grey wolves, the wolf populations have remained genetically distinct from dogs, suggesting that such cross-breeding does not diminish distinctiveness of the wolf gene pool if it occurs at low levels.

The results could have important conservation implications for the grey wolf, which is a keystone species -- meaning it is vital to the natural balance of the habitat it occupies. The legal status of hybrids is still uncertain and unregulated.

The study was led by researchers from the University of Lincoln, UK, the Italian National Institute for Environmental Protection and Research and the University of California, Los Angeles.

Dr Malgorzata Pilot, from the School of Life Sciences at the University of Lincoln, said: "The fact that wild wolves can cross-breed with dogs is well-documented, but little was previously known about how widespread this phenomenon has been and how it has affected the genetic composition of wild wolf populations.

Read more

Asian tigers at risk from domestic dog distemper virus

By Mark Kinver, Environment reporter, BBC News

Some of the world's rarest big cat species are facing a potentially deadly threat from a virus carried by domestic dogs, a wildlife expert has warned.

John Lewis, director of Wildlife Vets International, said there was evidence that Indonesian tigers were at risk.

Canine distemper virus has evolved in recent decades from infecting only dogs to affecting other animal groups.

Dr Lewis plans to work with Indonesian vets to develop a strategy to protect the nation's tigers from the virus.

A close relative of measles, Canine distemper virus (CDV) was first described at the beginning of the 20th Century and has been cited as contributing to the demise of the thylacine (commonly known as the Tasmanian tiger as a result of the black stripes on its back).

"If you wind the clock back about 30 or 40 years, it was a dog disease - it was a canine virus and only affected dogs," Dr Lewis explained.

"But in the intervening years, the virus has evolved and has changed its pattern of animals it can infect to include marine mammals (such as seals) and big cats."

Continued

Siberian Fossil Revealed to Be One of the Oldest Known Domestic Dogs

Mar. 6, 2013 — Analysis of DNA extracted from a fossil tooth recovered in southern Siberia confirms that the tooth belonged to one of the oldest known ancestors of the modern dog, and is described in research published March 6 in the open access journal PLOS ONE by Anna Druzhkova from the Institute of Molecular and Cellular Biology, Russian Federation, and colleagues from other institutions.

Human domestication of dogs predates the beginning of agriculture about 10,000 years ago, but when modern dogs emerged as a species distinct from wolves is still unclear. Although some previous studies have suggested that this separation of domestic dogs and wolves occurred over 100,000 years ago, the oldest known fossils of modern dogs are only about 36,000 years old.

The new research published today evaluates the relationship of a 33,000 year old Siberian fossil to modern dogs and wolves based on DNA sequence. The researchers found that this fossil, named the 'Altai dog' after the mountains where it was recovered, is more closely related to modern dogs and prehistoric canids found on the American continents than it is to wolves.

They add, ""These results suggest a more ancient history of the dog outside the Middle East or East Asia, previously thought to be the centers where dogs originated."

http://www.sciencedaily.com/releases/2013/03/130306221139.htm

Ancient dog skull unearthed in Siberia

A very well-preserved 33,000 year old canine skull from a cave in the Siberian Altai mountains shows some of the earliest evidence of dog domestication ever found.

But the specimen raises doubts about early man's loyalty to his new best friend as times got tough.

The findings come from a Russian-led international team of archaeologists.

The skull, from shortly before the peak of the last ice age, is unlike those of modern dogs or wolves.

The study is published in the open access journal Plos One.

Although the snout is similar in size to early, fully domesticated Greenland dogs from 1,000 years ago, its large teeth resemble those of 31,000 year-old wild European wolves.

This indicates a dog in the very early stages of domestication, says evolutionary biologist Dr Susan Crockford, one of the authors on the study.

"The wolves were not deliberately domesticated, the process of making a wolf into a dog was a natural process," explained Dr Crockford of Pacific Identifications, Canada.

But for this to happen required settled early human populations: "At this time, people were hunting animals in large numbers and leaving large piles of bones behind, and that was attracting the wolves," she said.

The most curious, least fearful wolves tended to have more juvenile characteristics with shorter, wider snouts and smaller, more crowded teeth, features that, over generations, came to define the domesticated dog.


These early dogs would have been useful to people in cleaning up scraps and fending off other predators such as bears, but after the ice age, over the last 10,000 years, they became key members of the team, believes Oxford University archaeologist Professor Thomas Higham, a co-author on the study.

"When you've got hunting dogs, all of a sudden it's a game changer. Hunters with dogs are much better than sole hunters," he told BBC News.

Intriguingly though, this much older early Siberian dog seems to have hit an evolutionary dead end. While people continued to occupy the Altai through the depths of the last ice age, they seem to have done so without their dogs, perhaps as food became more scarce.

"What the ice age did was to cause people to move around more," said Dr Crockford, halting the process of domestication and setting wolves and people back into competition for perhaps 20,000 years.

Fortunately, the closest modern dog, the Siberian Samoyed bred to herd and guard reindeer, seems to have taken up where its ancient predecessor left off.

By Hamish Pritchard

Science Reporter

http://www.bbc.co.uk/news/science-environment-14390679