The ancient and extinct terrible wolf could have been one of the loneliest wolves, so genetically differentiated from its closest wolf relative that it could no longer be crossed, forcing it to have an evolutionary dead end when it became extinct 13,000 years ago. years.
This is the finding based on a new study, the in-depth analysis of DNA recovered from ancient wolf bones from all over North America. Once terrible wolves (The dog darkens) diverged from the gray wolves millions of years ago, it seems they have never mixed since.
In fact, their genetic lineage is so different from other canids that the research team proposes that terrible wolves be placed completely in another genus, to be reclassified as Aenocyon dirus, as first proposed in 1918.
“Furious wolves are sometimes portrayed as mythical creatures (giant wolves roaming desolate icy landscapes), but the reality turns out to be even more interesting,” said paleobiologist Kieren Mitchell of the University of Adelaide in Australia.
“Despite the anatomical similarities between gray wolves and bad wolves, suggesting that they might be related in the same way as modern humans and Neanderthals, our genetic results show that these two species of wolves are very similar. more to distant cousins, such as humans and chimpanzees. “
Remains of hard wolves can be found in the fossil record from 250,000 to about 13,000 years ago, and appear to have dominated the carnivore scene during the last ice age in present-day North America.
Only in the famous tar pits of La Brea, the individuals of terrible wolves excavated outnumber the slightly smaller gray wolf (Canis lupus) more than a hundred times.
But as they diverged, evolved, and finally became extinct toward the end of the last glacial period, about 11,700 years ago, it has been a challenge to unite. So an international team of scientists set to work on one of the only clues we have: bones.
“Bad wolves have always been an iconic representation of the last ice age in the Americas, but what we know about their evolutionary history has been limited to what we can see by the size and shape of their bones,” he said. say archaeologist Angela Perri, of Durham. University.
But sometimes paleontological remains can contain other information inside them: DNA preserved well enough to be sequenced. And that’s what the team investigated.
They obtained five terrible wolf DNA samples from more than 50,000 years ago to 12,900 years ago, from Idaho, Ohio, Wyoming and Tennessee, and sequenced them.
They were then compared with genomic data from eight currently living canids, obtained from a genomic database: gray wolf, coyote (Canis latrans), African wolf (Canis lupaster), dhole (Cuon alpinus), Ethiopian wolf (Canis simensis), African wild dog (Lycaon pictus), Andean fox (Lycalopex culpaeus) and the gray fox (Urocyon cinereoargenteus).
They also generated new genome sequences for the gray wolf, the black-backed jackal (Canis mesomeles) and the side striped jackal (Canis).
They found that, unlike other wolves that migrated between regions, the nefarious wolf remained in position, never leaving North America.
And, fascinatingly, even though they shared space with coyotes and gray wolves for at least 10,000 years, they never seem to have come together with them to produce hybrids.
“When we started this study, we thought the terrible wolves were just reinforced gray wolves, so we were surprised to learn how they were genetically different, so much so that they probably couldn’t have been mixed,” said molecular geneticist Laurent Frantz from Ludwig Maximilian University in Germany and Queen Mary University in the United Kingdom.
“That must mean that terrible wolves were isolated in North America for a long time to become so genetically different.”
In fact, according to the team’s analysis, terrible wolves and gray wolves must have diverged from a common ancestor more than 5 million years ago. If you consider that dogs and wolves diverged between 15,000 and 40,000 years ago, it’s very long.
Mixing between canid species whose territories overlap is quite common. The hybrid of a coyote and a wolf is so common that it has a name – wolf coyote – and wolf-dog hybrids are also unknown (although breeding as a pet is highly controversial in the US). Therefore, it is very unusual for terrible wolves to have spent so much time in close proximity to canids without interbreeding.
And while the team didn’t explore that possibility, the genetic isolation may have contributed to the extinction of the old beast, as it was unable to adapt to a changing world with new traits.
“While ancient humans and Neanderthals appear to have interbreeded, as did modern gray wolves and coyotes, our genetic data provided no evidence that terrible wolves interbreed with any living canine species,” he said. Mitchell. “All of our data indicate that the wolf is the last surviving member of an ancient lineage different from all living canines.”
The research has been published in Nature.