DNA Dates Dog Domestication Back 33,000 Years
Tibetan wolf. A subspecies of grey wolf similar to this is thought to have given rise to the world’s first dogs, according to new research.
DNA analysis, as well as historical information, is helping to reveal the world's most ancient dog breeds. A new study, published in the journal Proceedings of the Royal Society B, puts the spotlight on East Asia as being a primary origination point for dog domestication. The earliest known dog-like fossils come from Europe, but it is likely that these dogs did not produce large populations that led to distinctive breeds. Genetic research on existing dogs reveal that certain breeds stand apart from others. "Our results show that these breeds represent lineages older than modern European breeds, and in this sense can be considered as ancient," senior author Wiesław Bogdanowicz of the Polish Academy of Science's Museum and Institute of Zoology, told Discovery News. Afghan hounds fall into the ancient group. In fact, they were called "ancient" long before the advent of genomics. In 1925, an article published in "The Dog Fancier" had the declarative title: "The Afghan Hound Is an Ancient Breed." Canine experts at the time even thought that the dogs "entered the ark with Noah" and were the world's first ever dogs. According to the historical record, Afghan hounds date back to the pre-Christian era of northeastern Afghanistan. The original name for the breed, famous for its silken coat and fashion model thin build, was "Tazi."Photos: The Earliest Dogs
Basenjis look remarkably like dogs featured in ancient Egyptian art. Drawings found in the tombs of the 2700 B.C. Great Pyramid of Khufu show such dogs seated near the feet of their owners, or under chairs. The cat-loving Egyptians might have taken to the dogs because, like felines, these canines tend to be relatively quiet and wash themselves regularly with their tongues. Most researchers, including Bogdanowicz and his team, still believe that domesticated dogs largely arose in Asia and migrated to other regions. "It is very likely that migrating populations of early farmers were followed by dogs," he said, explaining that these dogs were not feral, but were originally free-breeding. Basenjis possess a very distinctive suite of characteristics, which must have been maintained by human breeders. While the official breed only dates back 60 years, these dogs clearly have been in existence for centuries.Wolves Are Kinder, More Tolerant Than Dogs
Carina Wicke, Wikimedia Commons
Nearly all DNA studies of dogs find that Arctic breeds, such as the Alaskan malamute, stand apart from modern breeds. An extensive genomic investigation conducted by senior author Robert Wayne from the University of California at Los Angeles and colleagues found that Alaskan malamutes, as well as American Eskimo dogs and Siberian huskies, "are highly divergent from other dog breeds." This means that they have evolved on a slightly different path than other, more modern dogs. Wayne and his team added that "historical information suggests that most have ancient origins, greater than 500 years ago."Dogs Migrated to America After Humans
"Saluki" is thought to derive from two early Sumerian words meaning "plunge-earth." What that means exactly, in reference to the dogs, remains a mystery, but it is known that Salukis were historically bred in the Fertile Crescent where agriculture is widely believed to have originated. Like Afghan hounds, Salukis tend to have long legs and a thin build. They are known as sight hounds, meaning that they hunt primarily by sight as opposed to by smell or other senses. Today, they are bred with coats in a veritable rainbow of colors ranging from red to tricolor (white, black and tan).
The Greenland sled dog, also sometimes referred to as a sledge dog, is yet another early East Asian breed. The recent DNA analysis conducted by Bogdanowicz and his colleagues "revealed post-divergence gene flow from grey wolves to Greenland sledge dogs," they wrote. This determination reminds that free-breeding dogs can still interbreed with wild canines, such as grey wolves, coyotes and golden jackals. The resulting offspring can be fertile, and conservationists are concerned that we may one day lose the uniqueness of wild canine species due to hybridization.Oldest Dog Turns Out to Be a Wolf
Wayne and his team found that only two East Asian breeds, the chow chow and Akita, "had higher (genomic) sharing with Chinese wolves" than other breeds. Researchers can therefore see past wolf contributions to the modern dog genome. Other wolf populations noted in the dog DNA studies include those from North America, the Middle East and Europe.Dogs and Humans Bonded Earlier Than Thought
Judith Russell, Wikimedia Commons
The Samoyed, as a distinctive breed, originated in Siberia, where nomadic reindeer herders bred them as sled dogs and to help with herding. Their historical past is much deeper, however, as these primitive dogs descend from an even earlier, founding population of Russian dogs. According to an American Kennel Club fact sheet, "Of all modern breeds, the Samoyed is most nearly akin to the primitive dog. No admixture of wolf or fox runs in the Samoyed strain."Old Dog, New Origin: First Pooches Were European
The genetic analysis of Wayne and his team defined three basic groups of "highly divergent, ancient breeds." They are: *Asian group: dingo, New Guinea singing dog, chow chow, Akita and Chinese Shar Pei *Middle Eastern group: Afghan hound and Saluki *Northern group: Alaskan malamute and Siberian husky All of these dogs were found to be genetically "distinct from modern domestic dogs."Video: Dogs Have Feelings, Too
Bogdanowicz and colleagues' study suggests that the Shiba Inu belongs on the ancient dog list. The DNA of this dog shows that it is related to yet another East Asian breed, the Chinese Shar Pei. The American Kennel Club, though, reports that "Shibas are considered the oldest and smallest of Japan's dogs." The AKC only officially recognized this breed in 1992, demonstrating that the actual origin of a breed can happen hundreds of years prior to such designations.
The word "spitz" refers to several different breeds that loosely share common ancestry and traits. They are believed to descend from very ancient dog populations. Bogdanowicz told Discovery News that he and his team "found that spitz-type breeds of European origin -- Keeshond, Elkhound, Finnish Spitz, German spitz and Schipperke -- are genetically distinct from other European dog breeds, suggesting that they may have a distinct origin and possibly may be related to spitz-type breeds from East Asia and the Arctic." A closer look at the friendly dog shown in this photo reveals many wolf-like characteristics, such as a dense and waterproof insulating coat. Dog breeders even categorize spitzes in a unique group that stands apart from the other umbrella terms that they often use to describe dogs: ancient, toy, spaniels, scent hounds, working dogs, mastiff-like breeds, small terriers, retrievers, herding and sight hounds. The spitzes are in a league of their own.What Do Dogs Tell Each Other by Wagging?
All dogs alive today can trace at least some of their ancestry back to dogs that were domesticated 33,000 years ago in southern East Asia, suggests one of the most extensive ever investigations of canine DNA.
In addition to pinpointing the place and time for the earliest dog domestication, the new study, published in the journal Cell Research, found that the first domesticated dogs descended from grey wolves that likely came from China.
The research, conducted by an international team, further determined that dogs began to migrate out of East Asia and towards the Middle East and Africa 15,000 years ago. They then reached Europe in large numbers approximately 10,000 years ago. It appears that the dogs self-initiated the moves.
"For some reason, dogs stayed around East Asia for a long time before their migration out of Asia," senior author Ya-Ping Zhang of the Chinese Academy of Sciences Kunming Institute of Zoology told Discovery News. "We speculated that the glacial period might have been the environmental factor that prevented dogs from migrating out of Asia."
For the study, Zhang, Peter Savolainen of the KTH- Royal Institute of Technology in Sweden, and their colleagues sequenced the genomes of 58 canines, including grey wolves, indigenous dogs from Southeast and Northeast Asia, village dogs from Nigeria, and numerous dog breeds from around the world.
Based on the DNA analysis, they found that dogs from Southeast Asia have a higher degree of genetic diversity than all other dogs. Such genetic diversity is an indicator of where a species originates. Additionally, these dogs were most closely related to grey wolves.
DNA remains a focus for research on the history of dogs because the fossil record for dogs in East Asia is so poor. Zhang said that the warm, humid conditions of the region are not favorable for preserving fossils. Also, there have not been many targeted excavations in the region.
“Yet another unfavorable detail is that the soil in southern East Asia is mostly quite acidic, pH often below 5, which makes bones dissolve within a few hundred years,” Savolainen said.
It could then be that no remains still exist for the world’s first major population of domesticated dogs.
It is often said that cats, loving the comforts provided by humans, domesticated themselves. A subset of wolves might have done something similar.
As Zhang said, “dogs at the time of migration out of East Asia might still have been very loosely engaged with humans. Dogs might have followed existing human settlements and spread as scavengers living around human beings.”
Just as humans travel back and forth, it appears that some of the earliest dogs did too. The DNA evidence suggests that dogs from a group that migrated out of southern East Asia later travelled back, but this time toward northern China. There, the dogs interbred with local populations before spreading to the Americas, according to the new research.
Intriguingly, two excavated early dog skulls, analyzed by other scientists, date to 33,000 years ago. One was found in a cave in the Altai Mountains of Siberia. Another was discovered in a cave in Belgium.
"Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics," said Greg Hodgins, a researcher at the University of Arizona's Accelerator Mass Spectrometry Laboratory.
Several possibilities could explain both the DNA evidence and the archaeological finds. One is that humans were migrating frequently and over long distances 33,000 years ago, and dogs followed. The second, according to Hodgins, is that dog domestication happened repeatedly throughout early human history at different geographical locations. That would mean modern dogs have multiple ancestors, however, rather than a single common ancestor, as the new research indicates.
Dogs are one of the most studied animals, and yet even with all of the new findings, many unsolved mysteries about the origins of man’s best friend still remain.