YAKUTSK, September 16. /TASS/. All modern wolves may originate from Siberia, and most likely, they got into Europe and North America from north-eastern Asia, including its Arctic territories, a research team’s member, head of the mammoth fauna department at Yakutia’s Academy of Sciences, Albert Protopopov, told TASS.
The Nature magazine has published results of the research, conducted by an international team of scientists.
"We have identified an approximate time, when dogs began separating from wolves," the expert said. "It was about 28,000 years ago. The main centers, from where dogs have developed, are the Middle East and Central Asia. Besides, we have proved that all modern wolves most likely have the Siberian origin."
According to the scientist, wolves could get into Europe and North America from Asia’s north-east, including the Arctic territories.
Siberia - source of global gene flow
The researchers have tested long-term gene directions. "The research has found all wolves older 23,000 years are more like Siberian wolves than European or Central Asian wolves aged about 30,000 years. This means, the origin, related to Siberia, has spread to Europe," he continued.
"Although we were unable to distinguish the pulsed gene flow from the continuous one, our results show that Siberia acted as a source and Europe as a drain for the migration spanning the Late Pleistocene," he said. "There are no signs of gene flow in the other direction."
These results demonstrate not only a pervasive gene flow, but also find that the ancestral change was incomplete, and small parts of ancient European ancestors have survived to the present day. "Most of the studied modern Eurasian wolves, probably, retain a local Pleistocene pedigree <...> and contain 10-40% of that pedigree," he added.
According to the researchers, the majority of Eurasian wolves share "their ancestry within the last 25,000 years, the persistence of deep local ancestries provides evidence against widespread local extinction in Late Pleistocene Eurasia and suggests that the species as a whole, unlike many other megafauna, did not come close to extinction," the report reads.
Admixture with coyotes
The study also revealed that many modern and ancient North American wolves show evidence of coyote admixture. Scientists have found that wolves and coyotes began to diverge about 700,000 years ago.
"Our data show that coyote admixture has occurred at least since 100-80·ka, and two analyzed Pleistocene wolves from the Yukon also carried coyote mitochondrial lineages. These findings imply that either the Pleistocene range of coyotes extended further north than currently thought or that admixture occurring further south propagated northwards through the wolf population," the scientists said.
According to them, Eurasian wolves have not had any admixtures of coyote ancestors for a long time. "We found a slight west-east gradient of increasing coyote affinity among Eurasian wolves, but this pattern probably reflects admixture into coyotes from North American wolves (which are related to wolves in eastern Siberia)," the article notes.
After taking into account the admixture of coyotes, the group of experts found that wolf ancestry wolves in Alaska were highly connected to Siberia for a long time. "This mirrors European wolf history, but, while some deep local European ancestry persists, no deep North American ancestry appears to persist to the present," the scientists concluded.
According to scientists, Eurasian wolves have not had any admixtures of coyote ancestors for a long time. "In Eurasian wolves, we found a slight gradient of increasing affinity with coyotes from west to east. But this pattern probably indicates the admixture of North American wolves to coyotes, which are related to wolves from Eastern Siberia," the article reads.
The Bering land bridge probably allowed for an influx of Siberian wolves into Alaska intermittently between 70,000 and 11,000 years ago. However, the researchers found no evidence of gene flow in the other direction.
"All present-day North American wolves can be modelled as having 10-20% coyote ancestry and the remaining ancestry from Siberian wolves younger than about 23,000 years, with no contribution from earlier North American wolves. We found that red and Algonquin wolves similarly fit as shifted towards coyotes along this two-source admixture cline, but we cannot rule out greater complexity in their history," the article reads.
According to the research team, "dogs share more genetic drift with wolves that lived after 28,000 years ago than with those that lived before this time, which implies that the progenitors of dogs were genetically connected to other wolves at least until 28,000 years ago."
The geographical origin of the present-day dog lineage (Canis familiaris) has remained controversial. Genetic studies have argued that wolves in East Asia, Central Asia, the Middle East, Europe, Siberia, or both eastern and western Eurasia independently, contributed ancestry to early dogs, whereas others have been consistent with a single, but geographically unknown, progenitor population.
The scientists found that "dogs showed relationship profiles similar to those of Siberian wolves from 23,000 to 13,000 years ago. European wolves postdating 28,000 years ago have an affinity to <…> European wolves, reflecting the persistence of deep west Eurasian wolf ancestry. The absence of such western affinities in dogs suggests that they did not originate from the European wolf populations sampled here."
Though north-eastern Siberian wolves of 23,000 - 12,000 years ago demonstrate the biggest similarity with dogs, they were not the immediate ancestors of dogs, the scientists said.