Short Wave - 'Ghost Genes' Could Help Save The American Red Wolf

Episode Date: October 22, 2024

Every American red wolf alive right now is descended from only 14 canids. In the 1970s, humans drove the red wolf to the brink of extinction. Because of that, red wolves today have low genetic diversity. But what if we could recover that diversity ... using "ghost genes"? That's right, today's episode is a ghost story. Along the way, we get into gene dictionaries, the possibilities of poo and how a photo of a common Texas coyote started it all.Have another animal you want us to dig into for a future episode? Email us at [e-mail]!See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave, from NPR. Hey, short wavers, Emily Kwong here. So today, I'm going to tell you a ghost story. About an animal that once roamed free across the American southeast, the red wolf. A wolf with a cinnamon-colored coat that preyed upon deer and small mammals, which allowed birds and vegetation to thrive. But early European settlers, were afraid of these wolves. They saw them as dangerous predators. And as the number of people

spreading across the continent went up, the number of red wolves went down. The decline of red wolves in the wild were due to two primary factors. And the first one is indeed the predator elimination program. People were hunting and trapping and killing them. Bridget von Holt is a professor of ecology and evolutionary biology at Princeton University. And besides hunting, the other thing that led to the Red Wolf's decline was hybridization. Red wolves couldn't find other Red Wolfmates, so they started breeding with coyotes. So by the mid-1900s, Red Wolves had been pretty effectively eliminated from the landscape on a very rapid decline. And that's when there was an outcry for people to say, we actually need.

to save the species before it goes extinct. And these early American conservationists felt something had to be done. So by 1970, the Fish and Wildlife Service made a plan, a very bold decision to make the Red Wolf go extinct in the wild by capturing as many of the last ones as they could and transferring them into a captive breeding facility under human care. And they trapped hundreds of canids. And from these hundreds of canids they captured, fish and wildlife bred the 40 that seemed the most red wolfish, before ultimately creating a founder population of 14 red wolves. And those 14 then set on this classic path of breeding,

creating a new captive population that would represent the entire species. Today, there are only a few. few hundred red wolves in captive breeding programs and a few that have been released into the wild. It's less than 20 now roaming a peninsula in North Carolina. And for a while, scientists thought that was it. That captive breeding from the 14 red wolves that started the program was the best they could do, even though it severely limited the diversity of their genes. But then, and this is where the ghost story comes in, in 2016, a community scientist named Ron Wooten sent to Bridget, a picture. He had seen this coyote in his backyard in Galveston Island, Texas,

and that picture changed everything. Because when Bridget looked at it, it was like staring into the face of a ghost. So today on the show, reviving Red Wolves was science. You're listening to Shortwave, the science podcast from NPR. Okay, Bridget, so let's pick up with Ron Wooten, this community scientist from Galveston, Texas, he sends you this photo of a coyote in his backyard, but there was something different about this coyote. Yes. And the moment I saw the picture, I agreed. And this is against my better judgment,

because I try not to use the way an animal looks to infer its ancestry, except my gut said there is something absolutely astonishing about this animal. And it doesn't look like a dog. It doesn't look like anything but a red wolf. Hiding in the body and the body of a coyote. Hiding. Wow. Okay. And it inspired your research project, this genetic effort to bring the red wolf out of the coyote. And we're going to talk about the science of that in a bit.

But first, just to clarify, red wolves are no longer considered extinct. Right? We have hundreds of red wolves now in captivity and a handful of them living in the wild in North Carolina. So why can't we just breed those with each other? other and call it a day. Right. So classic conservation strategies, having this population that's managed in a facility, and humans play the role of matchmaker. A human needs to come in and monitor who should not be breeding? And those are relatives. You do not want to have close relatives or, you know, any relatives at all in this endangered species context. No, it's bad for genetic diversity.

And we need to keep these wolves cute. And the way to keep them cute is have them not making babies with their relatives. Yeah. I said that we had the captive breeding program founded by 14 individuals. Half of them are males. Half of them are females. So you only have seven breeding pairs, seven litters. Yeah.

So now you have if each litter is four pups, then you can start adding them up and start looking at, well, gosh, who should I pair together next year who aren't related? And very quickly, everybody is going to share a relationship in that population. So genetic health will dwindle over time and pretty rapidly if you start with such a small founder population. We can't just go to Mississippi and pluck one out of the wild and say, come and make my population healthier. We don't have that option. We can't make something out of nothing. So there is a plan to bring back the Red Wolf species to be robust and genetically diverse using ghost genetics that are found in coyotes. But like coyotes that are hybridized.

Yes. I do want to be very specific on the language I use. So these are coyotes. And the coyotes are not hybrids. They're admixtures. or they're just mixed ancestors. When they carry Red Wolf DNA, I call them ghost wolves. The goal is to find a way to bring that ghost DNA to the surface,

to try to accumulate it all into a few individuals. So putting the pieces of a puzzle back together. Okay. So when you're looking through all of these different genetic samples, How can you even tell what's what? Like, how can you say this gene came from before 1970, before this captive breeding program, this is a coyote gene versus this was a red wolf gene?

And then this is a mystery gene that doesn't, are you like matching the genetic material to like a dictionary? Yep, basically I've built an incredible dictionary across hundreds of thousands of nucleotides that I know are from wolves or, dogs or coyotes or whatnot. I'm a North American canine specialist, so I've gone through as many different varieties as possible and built these catalogs. So every type of coyote you can imagine, every type of wolf, every, you know, I've got dogs. So I could basically go through

and try to match it and say, what does its DNA look like? And every red wolf we know of today can be traced back to 14 founders. But we know that prior to 1980 and even 100, 200 years ago, there were a whole lot more than 14 Red Wolves that lived. Because of this hybridizing between Red Wolves and Coyotes back in the 70s, all of this other Red Wolf DNA never got translocated into the captive breeding program. So that's the ghost, is I suspect we're looking at Red Wolf DNA that's just never been

seen before. I have actual chill because it's almost like the genetic diversity you've been looking for that was not possible in that original OG group of 14 wolves. Yeah. It lived on in the wild. Yes. Okay, so how are you going to find these ghost wolves out in the wild? Part of our effort is to try to maximize the landscapes that we can start looking for ghost wolves.

That is done most easily if we can get the information about DNA and ancestry from a really accessible material. and that is ending up to be coyote poo. Uh-huh. Okay. Love poop. How does that work? So this is a non-invasive tool that if anybody picks up something that looks like it's a coyote poo, we first genetically can test it to make sure it's not a dog poo or something else, a fox, a fox poo.

So that way we can just send out a whole bunch of volunteers in giant fields, have them pick up poo, do some quick genetic testing in the lab, and that will help us pinpoint which areas contain animals that have this very special mixture of Red Wolf and Ghost Wolf genetic ancestry. Okay, so you're looking for poo samples and subsequently the animals who created that poo to find those with the highest amount of Red Wolf and Ghost Wolf genes. Yeah, you know, we can call it a wolfiness scale, actually. and the higher you are on the wolfiness scale, we hypothesize that the animal actually changes in how it looks and behaves.

So we can rank individuals after we've been watching them for a couple years and getting this data. We'll rank them on priority for who's going to be the most unique and wolfy candidate. Okay, I think I'm getting it. So after you identify some promising wolfy candidates, candidates in the wild, what happens next? What we're wanting to do is create a tiny breeding experiment. I think we're going to do somewhere like four to six animals who have scored really high on the wolfiness. Hopefully the wolves will be very happy with the pairings that we make.

But we want them to have litters to help concentrate all of this unique ghost genetics down into a few pups. And then when they have this litter of pups, we'll go through the same evaluation. We'll look at their DNA. We'll watch them as they grow. We'll look at their behavior. And we'll repeat that experiment one or two times. So in the end, are you just making like a new more genetically diverse Red Wolf? Like what are you hoping for in terms of results?

What we want to do with this project is, two different types of goals. The first one is what we call basic science. We want to really understand how red wolf ancestry and ghost wolf ancestry, how this manifests itself in an animal. But when it comes to conservation, if we can actually have very confident findings that the more red wolfy an animal is,

then the more valuable it becomes in providing a resource for new genetic material that we could ultimately, hopefully bring back into the Red Wolf Captive Breeding Program. Okay. So you're trying to introduce genetic diversity into the existing Red Wolf captive breeding program through these new ghost wolves, which you're like bringing back into existence with this project. Yeah.

And two generations is probably not enough, but I think it could be very quickly after that, a handful more generations. How long do you think it would take to get there? Just out of curiosity, like decades? No, no. We have a five-year funded project. So by the end of five years, I think we would have a really good sense of how close we are. I think it's very close, like within a decade for sure.

I would dare say within five years. But, you know, we need to be fast. Biodiversity is being lost all the time. Species are going extinct all the time. And we can't wait. Bridget, thank you for bringing us this ghost story from the world of genetics. Thank you so much. This episode was produced by Hannah Chin and edited by our showrunner, Rebecca Ramirez.

This fact-checked by Tyler Jones. Robert Rodriguez was the audio engineer. Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Emily Kwong. Thanks for listening to Shortwave from NPR.