Two gray wolves (bottom left) confronted a bunch of bad wolves over a bison carcass in southwestern North America 15,000 years ago. Credit: Art by Mauricio Anton
The iconic, prehistoric distressed wolf, which roamed Los Angeles and elsewhere in the Americas more than 11 millennia ago, was a distinct species of the slightly smaller gray wolf, an international team of scientists reported in the journal. Earth.
The study, which is a mystery in bed that biologists have been pondering for more than 100 years, was led by researchers from UCLA, together with colleagues from Durham University in the United Kingdom, the Australian University of Adelaide and the German Ludwig Maximilian University. .
“The terrifyingly troubled wolf, a legendary symbol of Los Angeles and the La Brea Tar Pits, has earned its place among the many large, unique species that became extinct at the end of the Pleistocene era,” said Robert Wayne of UCLA. a leading professor, said. of ecology and evolutionary biology and the co-author of the study. The Pleistocene, commonly called the Ice Age, ended about 11,700 years ago.
More than 4,000 horrible wolves have been exhumed from the La Brea Tar Pits, but scientists still know little about their evolution or the reasons for their eventual disappearance. Gray wolves, which also occur in the fossil-rich pits, have survived to this day.
“Dirty wolves have always been an iconic representation of the last ice age in the Americas, but what we know about their evolutionary history is limited to what we can see from the size and shape of their bones,” said Angela, co-lead author. , said. Perri of Durham University.
These bones now reveal much more. Using leading molecular approaches to analyze five distressed wolf genomes from fossil bones from 13,000 to 50,000 years ago, the researchers were able to reconstruct the evolutionary history of the long extinct carnivore for the first time.
Importantly, they found no evidence for the flow of genes between distressed wolves and North American gray wolves or prericots. The absence of genetic transmission indicates that serious wolves evolved in isolation from the ancestors of the ice age of these other species.
‘We found that the horrible wolf is not closely related to the gray wolf. Furthermore, we showed that the awful wolf never intervened with the gray wolf, ”said co-lead author Alice Mouton, who conducted the research as a postdoctoral fellow at UCLA in ecology and evolutionary biology in the Wayne laboratory.
The ancestors of the gray wolf and the much smaller prairie variety evolved in Eurasia and are thought to have migrated to North America less than 1.37 million years ago, relatively recently in evolutionary time. In addition, the horrible wolf, on the other hand, is based in the Americas, based on the genetic difference of the species.
“When we first started this study, we thought horrible wolves were just associated gray wolves, so we were surprised to hear how extremely genetically different they were, so much so that they probably could not cross,” said the study. author, Laurent Frantz, a professor at Ludwig Maximillian University and the British Queen Mary University. “It must mean that the wolves have been isolated in North America for a very long time to be so genetically distinct.”
“Terrible wolves are sometimes portrayed as mythical creatures – giant wolves scurrying around frozen landscapes – but the reality seems even more interesting,” said Kieren Mitchell of the University of Adelaide, a co-lead author.
The awful wolf was a ‘lone wolf’ when it comes to breeding
Breeding is very common among wolf lines as their geographical variations overlap. Modern gray wolves and coyotes, for example, cross regularly in North America. Yet, using a dataset that included a serious Pleistocene wolf, 22 modern North American gray wolves and coyotes, and three ancient dogs, the researchers found that the distressed wolf did not interfere with any of the others – probably because it was genetically incapable. to reproduce with those species.
‘Our finding of no evidence of gene flow between distressed wolves and gray wolves or coyotes, despite the great overlap of the variety during the late Pleistocene, suggests that the common ancestor of gray wolves and prairie birds was probably in geographical isolation from members of the serious wolf descent has developed. , ”Said Wayne. “This result is consistent with the hypothesis that distressed wolves originated in the Americas.”
Another hypothesis about the horrible wolf – one that has not been tested in the current study – concerns its extinction. It is generally thought that the horrible wolf, because of its body size – larger than gray wolves and coyotes – was more specialized in hunting large prey and could not survive the extinction of its regular food sources. Mouton, now a postdoctoral researcher at the Belgian University of Liège, could potentially undermine a lack of interbreeding.
“Perhaps the ominous wolf’s inability to cross did not provide the necessary new traits they could survive,” she said.
Discover the mystery of the horrible wolf’s DNA
While the precocious wolves followed up in this study had no ancestry from gray wolves, coyotes, or their recent North American ancestors, a comparison of the DNA of serious wolves with those of gray wolves, coyotes and a wide variety of other wolf-like species, revealed a common but far evolutionary relationship.
“The ancestors of distressed wolves probably deviated from those of gray wolves more than 5 million years ago – it was a great surprise to discover that this deviation occurred so early,” Mouton said. “This finding underscores how special and unique the troubled wolf was.”
Based on their genomic analyzes, the researchers also concluded that there are three primary descendants descended from the shared descent: horrible wolves, African foxes and a group consisting of all other existing wolf-like species, including the gray wolf.
Gray wolves, which today mostly live in the wilderness and remote regions of North America, are more closely related to African wild dogs and Ethiopian wolves than to distressed wolves, Wayne noted.
The study is the first ever to report genome-wide data on serious wolves.
The genomic analyzes – carried out in a joint effort at UCLA, Durham University, the University of Oxford, University of Adelaide, Ludwig Maximilian University and Queen Mary University – focused on both the nuclear genome and the mitochondrial genome, which are abundant in ancient remains.
“The lower cost of sequencing analyzes, in addition to the latest molecular biology methods for highly degraded materials, enables us to recover DNA from fossils,” Mouton said. “Ancient DNA genomic analyzes are an incredible tool for better understanding the evolutionary history of ancient and extinct species.”
Reference: “Dire wolves were the last of an ancient New World canid lineage” 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, Earth.
DOI: 10.1038 / s41586-020-03082-x
The 49 co-authors of the study also include Blaire Van Valkenburgh, a leading professor of ecology and evolutionary biology at UCLA, who holds the chair of Donald R. Dickey in Vertebrate Biology; Julie Meachen, who earned her Ph.D. in ecology and evolutionary biology from UCLA and is now an associate professor of anatomy at Des Moines University in Iowa; and Colin Shew, a UCLA laboratory technician in ecology and evolutionary biology; as well as dozens of other researchers from the United Kingdom, Australia, Germany, Russia, Spain, France, Denmark and other countries.
Funding sources for the research were the National Science Foundation, the Office of Naval Research, the Marie Curie COFUND, the European Research Council, the Natural Environmental Research Council, the Wellcome Trust and the Australian Research Council. The Nature article contains many other acknowledgments.