Ancient DNA reveals secrets of ‘terrifying’ dreadful wolf – famous in Game of Thrones

The iconic, prehistoric wolf, which roamed Los Angeles and elsewhere in the Americas more than 11 millennia ago, was a distinct species from the slightly smaller gray wolf, an international team of scientists reported to the journal. Nature.

The study, which puts to bed a mystery that biologists have been investigating for more than 100 years, was conducted by researchers at UCLA, as well as colleagues at Durham University in the UK, from the Australian University of Adelaide and the German Ludwig Maximilian University.

“The terrible terrible wolf, legendary symbol of Los Angeles and the tar pits of La Brea, has earned its place among the many great unique species that became extinct at the end of the Pleistocene epoch,” said Robert Wayne of UCLA, a distinguished professor. of ecology and evolutionary biology and co-lead author of the study. The Pleistocene, commonly referred to as the Ice Age, ended about 11,700 years ago.

More than 4,000 terrible wolves have been unearthed in the La Brea tar pits, but scientists know little about their evolution or the reasons for their eventual demise. Gray wolves, also found in fossil-rich pits, have survived to this day.

“The dreaded wolves have always been an iconic representation of the last ice age in the Americas, but what we know of their evolutionary history has been limited to what we can see from the size and shape of their bones.” said co-lead author Angela Perri of Durham University.

These bones now reveal much more. Using cutting-edge molecular approaches to analyze five terrible wolf genomes from fossil bones dating back 13,000 to 50,000 years, researchers were able to reconstruct the evolutionary history of the long-extinct carnivore for the first time.

Significantly, they found no evidence of gene flow between terrible wolves and North American gray wolves or coyotes. The lack of any genetic transfer indicates that terrible wolves evolved independently from the Ice Age ancestors of these other species.

“We discovered that the terrible wolf is not closely related to the gray wolf. Plus, we’ve shown that the terrible wolf never crossed paths with the gray wolf, ”said co-lead author Alice Mouton, who led the research as a postdoctoral researcher at UCLA in ecology and biology. scalable in Wayne’s lab.

The ancestors of the gray wolf and the much smaller coyote evolved in Eurasia and would have arrived in North America less than 1.37 million years ago, relatively recently in evolution. The terrible wolf, due to its genetic difference from these species, is now believed to be native to the Americas.

“When we started this study, we thought that terrible wolves were just muscular gray wolves, so we were surprised to learn how extremely genetically different they were, so much so that they probably wouldn’t. could not reproduce, ”said the latest study. author, Laurent Frantz, professor at Ludwig Maximillian University and Queen Mary University in the United Kingdom. “It must mean that terrible wolves have been isolated in North America for a very long time to become so genetically distinct.

“Fearsome wolves are sometimes described as mythical creatures – giant wolves prowling in icy, dark landscapes – but the reality turns out even more interesting,” said Kieren Mitchell of the University of Adelaide, co-lead author .

The terrible wolf was a ‘lone wolf’ when it came to breeding

Interbreeding is quite common among wolf lineages when their geographic areas overlap. Gray wolves and modern coyotes, for example, are common in North America. Yet the researchers, using a dataset that included a terrible wolf from the Pleistocene, 22 modern North American gray wolves and coyotes, and three ancient dogs, found that the terrible wolf had not crossed paths with any of the others – probably because he was genetically incapable of reproducing with these species.

“Our finding that there is no evidence of gene flow between terrible wolves and gray wolves or coyotes, despite the substantial overlap of ranges in the Late Pleistocene, suggests that the common ancestor of gray wolves and coyotes probably has evolved in the geographic isolation of members of the terrible wolf lineage, ”Wayne said. “This result is consistent with the hypothesis that the terrible wolves originated in the Americas.”

Another hypothesis about the terrible wolf – which has not been tested in the current study – concerns its extinction. It is generally believed that due to its body size – larger than gray wolves and coyotes – the terrible wolf was more specialized in hunting large prey and was unable to survive the extinction of its regular food sources. A lack of interbreeding may have accelerated its demise, suggested Mouton, now a postdoctoral researcher at the University of Liège in Belgium.

“Perhaps the terrible wolf’s inability to reproduce did not provide the necessary new traits that could have allowed them to survive,” she said.

Uncover the mystery of the terrible wolf’s DNA

While the terrible wolves sequenced in this study did not possess any ancestry from gray wolves, coyotes, or their recent North American ancestors, a comparison of DNA terrible wolves along with that of gray wolves, coyotes, and a wide variety of other wolf-like species have revealed a common but distant evolutionary relationship.

“The ancestors of the terrible wolves probably diverged from those of the gray wolves over 5 million years ago – it was a big surprise to find that this divergence happened so early,” said Mouton. “This discovery underscores how special and unique the terrible wolf was.”

Based on their genomic analyzes, the researchers also concluded that there are three primary lineages that descend from common ancestry: terrible wolves, African jackals, and a group comprising all other extant wolf species, including the grey Wolf.

Gray wolves, which today mostly live in the wild and remote parts of North America, are more closely related to African wild dogs and Ethiopian wolves than to terrible wolves, Wayne noted.

The study is the first to report genome-wide data on terrible wolves.

Genomic analyzes – conducted as part of a joint effort at UCLA, Durham University, Oxford University, the University of Adelaide, Ludwig Maximilian University and Queen Mary University – focused on both the nuclear genome and the mitochondrial genome, which is abundant in ancient remains.

“The decrease in the cost of sequencing assays, in addition to advanced molecular biology methods for highly degraded materials, allows us to recover DNA from fossils,” Mouton said. “Genomic analyzes of ancient DNA represent an incredible tool to better understand the evolutionary history of ancient and extinct species.”

Reference: “The dreaded wolves were the last of an ancient New World canid line” by Angela R. Perri, Kieren J. Mitchell, Alice Mouton, Sandra Álvarez-Carretero, Ardern Hulme-Beaman, James Haile, Alexandra Jamieson, Julie Meachen, Audrey T. Lin, Blaine W. Schubert, Carly Ameen, Ekaterina E. Antipina, Pere Bover, Selina Brace, Alberto Carmagnini, Christian Carøe, Jose A. Samaniego Castruita, James C. Chatters, Keith Dobney, Mario dos Reis, Allowen Evin, Philippe Gaubert, Shyam Gopalakrishnan, Graham Gower, Holly Heiniger, Kristofer M. Helgen, Josh Kapp, Pavel A. Kosintsev, Anna Linderholm, Andrew T. Ozga, Samantha Presslee, Alexander T. Salis, Nedda F. Saremi, Colin Shew, Katherine Skerry, Dmitry E. Taranenko, Mary Thompson, Mikhail V. Sablin, Yaroslav V. Kuzmin, Matthew J. Collins, Mikkel-Holger S. Sinding, M. Thomas P. Gilbert, Anne C. Stone, Beth Shapiro, Blaire Van Valkenburgh, Robert K. Wayne, Greger Larson, Alan Cooper and Laurent AF Frantz, January 13, 2021, Nature.
DOI: 10.1038 / s41586-020-03082-x

The 49 co-authors of the study also include Blaire Van Valkenburgh, a distinguished professor of ecology and evolutionary biology at UCLA, Donald R. Dickey Chair in Vertebrate Biology; Julie Meachen, who received her PhD in Ecology and Evolutionary Biology from UCLA and is now Associate Professor of Anatomy at Des Moines University in Iowa; and Colin Shew, UCLA Laboratory Technician in Ecology and Evolutionary Biology; as well as dozens of other researchers from the UK, Australia, Germany, Russia, Spain, France, Denmark and other countries.

Sources of research funding included the National Science Foundation, Office of Naval Research, Marie Curie COFUND, European Research Council, Natural Environmental Research Council, Wellcome Trust and Australian Research Council. The Nature document lists many other acknowledgments.