Red Wolf DNA Discovered in Mysterious Texas Dogs

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Although red wolves were declared extinct in the wild in 1980, a team of biologists found their DNA in a group of dogs living on Galveston Island off the coast of Texas.

“This is a remarkable finding, as red wolves were declared extinct in this region more than 35 years ago and remain critically endangered,” said Elizabeth Heppenheimergraduate student from the laboratory of Bridgett vonHoldtassistant professor of ecology and evolutionary biology at Princeton. “Although there have been reports of ‘red wolves’ along the Gulf Coast, mainstream science has dismissed them as misidentified coyotes. Now we’ve shown that at least one example of a “red wolf sighting” has some validity, because these Galveston Island animals definitely carry genes that are present in the captive but absent red wolf population. populations of coyotes and gray wolves. Their work appears in the special issueConservation genetics and genomicsfrom the journal Genes.

Prior to this, the only known living red wolves (Red canislisten)) were a group reintroduced to North Carolina. Small wolves – larger than coyotes but smaller than the better-known gray wolves – once lived throughout the southeastern United States, but by the 1970s they were facing extinction. To save the species, the last known red wolves were trapped for a captive breeding program. They had already started interbreeding with coyotes, so of the 240 dogs captured, only 17 were considered 100% wolves. Of these, 14 bred successfully, and by 1990 a population of red wolves had been successfully reintroduced to North Carolina. The success of the red wolf recovery program has led to other reintroductions of wolves, including gray wolves (C. lupus) in the Yellowstone National Park area and ongoing restoration efforts for Mexican wolves (C. lupus baileyi) in the southwest.

Although initially ecologically successful, the red wolf population now has fewer than 40 surviving members, leaving them once again on the brink of extinction in the wild.

Wildlife biologist Ron Wooten spotted this pack of dogs on Galveston Island, Texas, in an area where red wolves were declared extinct more than 35 years ago. Princeton biologists Bridgett vonHoldt and Elizabeth Heppenheimer have identified that these canids share DNA with coyotes and a captive breeding group of red wolves. They also have unique genetic material that may represent genes that had been lost in the small wolf population that began the captive breeding program in the 1970s.

This study has its origins in wildlife biologist Ron Wooten, who observed a population of canids on Galveston Island. He sent an email vonHoldt’s laboratory requesting genetic testing on two roadkill animals.

“I get these kinds of requests regularly, but something about Wooten’s email was sticking out,” vonHoldt said. “His enthusiasm and dedication struck me, as well as some very intriguing photographs of the canines. They looked particularly interesting and I felt it was worth a look.

“Somewhere along the way the second sample got lost and he ended up sending us the dirty scalpel he used to take the sample, Heppenheimer said. “We have a huge inventory of coyote and wolf samples in the lab, and it’s pretty rare that I remember a sample arriving, but no one had ever sent us a scalpel before, that was so quite a memorable experience trying to extract that DNA.

After the researchers extracted and processed the DNA, they compared the samples to each of the legally recognized wild species of the genus. Canis that occur in North America. They used samples from 29 coyotes from Alabama, Louisiana, Oklahoma and Texas; 10 Gray Wolves from Yellowstone National Park; 10 Eastern Wolves (C. wild dog) Algonquin Provincial Park in Ontario; and 11 red wolves from the captive red wolf breeding program.

When they did their genetic analyses, they found that the animals on Galveston Island looked more like captive red wolves than typical southeast coyotes.

“I think we were all really surprised that there was any indication of red wolf genes in any of these samples,” Heppenheimer said. “We get strange samples pretty regularly, and most of the time it’s coyotes. …At first I was extremely skeptical that the analysis would turn up anything interesting, which ended up being very humbling. I consider myself an expert on these animals, but in reality most of the time I just watch my computer. It was the people on the ground, who regularly monitor these animals, who made the major discovery.

In addition to sharing genes unique to the captive red wolf population, the animals on Galveston Island also carried a unique genetic variation not found in any known North American canid.

“This variation may represent red wolf-derived genes that were lost as a result of captive breeding,” Heppenheimer said. “It’s incredibly rare to rediscover animals in an area where they were thought to be extinct, and it’s even more exciting to show that a piece of an endangered genome has been preserved in the wild.”

Because they can interbreed, coyotes and red wolves confuse the most commonly recognized definition of a “species,” meaning a group whose individuals can reproduce and produce viable offspring. But because that definition doesn’t account for organisms that reproduce asexually, such as bacteria, biologists also recognize many other definitions of species, Heppenheimer said. “Coyotes and wolves are considered separate species based on the concept of ‘ecological species,’ which recognizes wildlife as different species if they use different resources in their environment,” she said.

Wolves and coyotes prefer to breed with members of their own species, so hybridization only occurs under very specific ecological conditions, such as when population densities are so low that the animals are forced to choose between reproduce and give up reproduction altogether. Some recent studies have also shown that disturbing a mated pair also increases the chances of hybridization.

Likely because of this interbreeding, Galveston Island dogs are “ambiguous,” Heppenheimer acknowledged. “Even to the trained eye, coyotes and wolves can be notoriously difficult to distinguish from afar or in scale-free photography. That said, the more time you spend observing these animals, the more you begin to recognize subtle differences in shape of the snout or size of the ears.Official species markers depend on precise measurements, such as hind foot length and head width, which researchers did not have access to, as they used photographs and small samples taken on the road.

“It’s hard to pinpoint exactly what in these animals made them ambiguous, since we didn’t take any quantitative measurements, but the snout shape and overall size of the animals just didn’t seem quite right. correct for them to be pure coyote,” Heppenheimer said.

“Texas may be an appropriate location for future reintroduction efforts,” Heppenheimer said. If the reintroduced wolves breed with local coyotes, as has already started breeding in North Carolina, it could have an unexpected benefit, she said. “If hybridization occurs, ‘coyotes’ in the area may carry red wolf genes, and these hybridization events could restore red wolf genes that were lost as a result of the captive breeding program. .” Further research will be needed before this is done, she added.

In addition to Heppenheimer and vonHoldt, the research team included Kristin Brzeski, a former postdoctoral researcher in vonHoldt’s lab who is now an assistant professor at Michigan Technological University; Wooten, the wildlife biologist who provided the samples; William Waddell of the Point Defiance Zoo in Tacoma, Washington; Linda Rutledge of Trent University in Ontario, Canada; Michael Chamberlain and Joseph Hinton of the University of Georgia, Athens; and Daniel Stahler of Yellowstone National Park.

“This project was a huge collaborative effort, and all of the co-authors brought unique perspectives to this study,” Heppenheimer said. “In particular, Kristin Brzeski (who shares lead author credit) is an expert in contemporary red wolf genetics and conservation, whereas my training has focused more on patterns of genetic diversity in coyotes. . Bridgett vonHoldt, the project’s lead author, has the most experience in genome-scale studies and has overseen the entire project. The three of us, along with our other co-authors, really came together to properly analyze and interpret the data.

“This is a remarkable finding and encourages us to eventually redefine what is considered the ‘canonical coyote,'” vonHoldt said. “That may not actually exist in the American Southeast. Coyote populations may more likely represent a mosaic of individuals with diverse histories, some possibly carrying the remains of an extinct species. We hope these findings will resonate with policy makers and managers, and influence our thinking about endangered genetics.

Red wolf phantom alleles rediscovered in a canid population along the US Gulf Coastby Elizabeth Heppenheimer, Kristin Brzeski, Ron Wooten, William Waddell, Linda Rutledge, Michael Chamberlain, Daniel Stahler, Joseph Hinton and Bridgett vonHoldt was published December 10 in the “Conservation genetics and genomics» special issue of the journal Genes (DOI: 10.3390/genes9120618). Their work was supported by the Point Defiance Zoo and Aquarium Holly Reed Conservation Fund, the National Science Foundation (gdiatribes PRFB-1523859 and DEB-1245373)the Natural Sciences and Engineering Research Council of Canadait is Ontario Ministry of Natural Resources and Forestry, and Yellowstone forever.

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