Red wolf DNA found 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 canines living on Galveston Island off the coast of Texas.

“This is a remarkable find, as the red wolves were declared extinct in this region over 35 years ago and remain critically endangered,” said Elizabeth heppenheimer, a graduate student from the Bridgett von Holdt, assistant professor of evolutionary ecology and 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 have shown that at least one example of’ sighting red wolf “has some validity, as these Galveston Island animals certainly carry genes that are present in the captive red wolf population but absent from the coyote and gray wolf populations. Their work appears in the special issue “Conservation genetics and genomicsFrom the journal Genes.

Before that, the only known living red wolves (Canis rufus) 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 threatened with extinction. To save the species, the last known red wolves have been trapped for a captive breeding program. They had already started breeding with coyotes, so of the 240 canids captured, only 17 were considered 100% wolves. Of these, 14 have reproduced 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 further reintroductions of wolves, especially gray wolves (C. lupus) in the Yellowstone National Park area and the ongoing restoration efforts for Mexican wolves (C. lupus baileyi) at the South West.

Although initially ecologically successful, the red wolf population now numbers less 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 dogs share DNA with coyotes and a captive breeding group of red wolves. They also possess 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 lab ask for genetic tests on two animals killed on the road.

“I get this kind of request on a regular basis, but something in Wooten’s email came out,” vonHoldt said. “His enthusiasm and dedication struck me, along with some very intriguing photographs of the dogs. They looked particularly interesting and I thought it was worth taking a second 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 single sample arriving, but no one had ever sent us a scalpel before, so it was an experience. quite memorable to try to extract that DNA. “

After the researchers extracted and processed the DNA, they compared the samples to each of the legally recognized wildlife species in 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. lycaon) Algonquin Provincial Park in Ontario; and 11 red wolves from the captive red wolf breeding program.

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

“I think we were all really surprised that there was any indication of red wolf genes in either of these samples,” Heppenheimer said. “We get some weird samples that are shipped to us quite regularly, and most of the time they’re coyotes. … At first I was extremely skeptical that the analysis would lead to anything interesting, which ended up being very humiliating. I consider myself to be an expert on these animals, but in reality most of the time I just look at 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 of the known North American canids.

“This variation may represent genes derived from the red wolf 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 “species” – a group whose individuals can reproduce and produce viable offspring. But because this definition ignores organisms that reproduce asexually, like 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 mate with members of their own species, so hybridization only occurs under very specific ecological conditions, such as when population densities are so low that animals are forced to choose. between crossing and total abandonment of reproduction. Some recent studies have also shown that disrupting a mated pair also increases the chances of hybridization.

Probably because of this crossbreeding, Galveston Island canines are “ambiguous in appearance,” Heppenheimer admitted. “Even to a trained eye, coyotes and wolves can be notoriously difficult to distinguish at a distance or in a photograph without a scale. That said, the more time you spend looking at these animals, the more you begin to recognize subtle differences in muzzle shape or ear size. Official species markers depend on precise measurements, such as rear foot length and head width, which researchers did not have access to because they used photographs and small samples taken from the roads.

“It is difficult to determine exactly what made them ambiguous about these animals, as we took no quantitative measurements, but the muzzle shape and overall size of the animals just didn’t seem quite right to them. . pure coyote, ”Heppenheimer said.

“Texas could be a suitable location for future reintroduction efforts,” Heppenheimer said. If the reintroduced wolves breed with local coyotes, as has already started to breed in North Carolina, it could have an unexpected benefit, she said. “If hybridization occurs, the ‘coyotes’ in the area may carry red wolf genes, and these hybridization events could restore the red wolf genes that were lost as a result of the captive breeding program . ” More 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 Point Defiance Zoo in Tacoma, Washington; Linda Rutledge of Trent University in Ontario, Canada; Michael Chamberlain and Joseph Hinton from 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 a unique perspective to this study,” Heppenheimer said. “In particular, Kristin Brzeski (who shares the credit of lead author) is an expert in contemporary red wolf genetics and conservation, while my experience has focused more on patterns of genetic diversity in coyotes. . Bridgett vonHoldt, the lead author of the project, has the most experience with genome-wide studies and has overseen the entire project. The three of us, along with our other co-authors, really came together to analyze and interpret the data appropriately. “

This is a remarkable discovery that encourages us to eventually redefine what is considered the ‘canonical coyote,’ said vonHoldt. “It may not actually exist in the Southeastern United States. Coyote populations can more likely to represent a mosaic of individuals with diverse histories, some possibly bearing the remains of an extinct species. We hope these findings resonate with policymakers and managers, and influence how we think about genetics on the way. of disappearance. “

Red wolf ghost alleles rediscovered in canine population along the US Gulf Coast“Elizabeth Heppenheimer, Kristin Brzeski, Ron Wooten, William Waddell, Linda Rutledge, Michael Chamberlain, Daniel Stahler, Joseph Hinton and Bridgett vonHoldt was published on 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 Canada‘s Ontario Ministry of Natural Resources and Forestry, and Yellowstone forever.


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