Core tip: By analyzing DNA samples from prehistoric hounds and comparing them with the genes of modern dogs and wolves, researchers speculated that there may have been two groups of gray wolves (they lived thousands of miles apart in space and thousands of years in time) It successively established contact with humans and became a domestic dog.

Data map: Military dogs with great military exploits.

Reference News Network reported on June 15 that foreign media said that the long-term friendship between humans and dogs may have started twice. Gray wolves in western Eurasia may have been hanging out near primitive human settlements in the Stone Age, and later in East Asia, friendship between humans and dogs may have been established 14,000 years ago.

According to a report on the British "Guardian" website on June 2, researchers analyzed the DNA samples of prehistoric hounds and compared them with the genes of modern dogs and wolves, and speculated that there may be two groups of gray wolves (they lived in separate spaces). Thousands of miles and thousands of years apart) successively established contact with humans and became domestic dogs.

A recent article published in Science magazine said that this statement is still just speculation. For more than a decade, researchers have debated the origins of jackals, terriers and collies.

Greg Larson, head of the Ancient Genetics and Bioarchaeological Research Network at the Wellcome Trust at the University of Oxford, said: "Animal domestication is a rare event, and a lot of evidence is needed to overturn the hypothesis that a certain animal was domesticated only once."< /p>

"Our ancient DNA evidence, along with the archaeological record of early dogs, suggests we need to rethink the number of times dogs were independently domesticated. There is no consensus on where dogs were domesticated so far, perhaps because of what everyone says It all makes sense."

The domestication of cattle, sheep and goats began more than 10,000 years ago during the last Ice Age on primitive farms in the Fertile Crescent of Western Asia. The only animal known to have been domesticated twice is the pig, in East Asia and the Near East. Collies may experience the same thing. If so, gray wolves may have long been foraging for scraps near human settlements: it may have taken many generations for these wandering foragers to transition into humans' hunting companions.

Modern dogs seem to have a common origin: in 2005, geneticists studied the DNA of various dogs and determined that the ancestry of 400 breeds of modern dogs can be traced back to gray wolves that lived in East Asia about 15,000 years ago.

But researchers have discovered older dog bones buried with human remains in Europe, which seems to prove that dogs and humans established friendship in Europe long before East Asia.

Oxford University scholar Laurent Franz and colleagues choseThe skeletons of 59 dogs that lived in Europe between 3,000 and 14,000 years ago began to analyze mitochondrial DNA samples. They only selected DNA inherited from female dogs in order to more accurately trace their origins. They also analyzed the complete genome of a dog found in the Newgrange region of Ireland that lived about 5,000 years ago. They then compared the ancient canine DNA with the genes of 2,500 modern dogs and wolves.

"Once you domesticate an animal, the survival of its wild brethren becomes a problem," Larson said. "Like the aurochs, the ancestor of cattle: there is no trace of it now. And then there's the dromedary camel. We have Has a long and 'proud' history of erasing all kinds of living things."

"The wolf that gave birth to the dog is gone."

Researchers are analyzing more DNA samples from dogs and wolves in Stone Age Europe to find evidence that wolves and dogs' role transformation may only have originated in the West.

"This would be strong evidence. Likewise, if we find the bones of dogs and wolves that lived in Western Europe during the Early Mesolithic and Neolithic Ages, and if they are extremely similar to modern dogs, then dogs were domesticated twice The hypothesis is no longer tenable."

In addition to tracing the origins of dogs, Larson's lab is also working on solving other domestication mysteries: wild boars and domestic pigs, jungle pheasants and domestic chickens, and how the first buffaloes came into being. 's and so on. (Compiled/Guo Jun)