Tag Archives: dire wolf

De-extinction: the wooly mammoth is the biophysicist’s cancer

On my first day teaching bioinformatics, I brought Michael Crichton’s book Jurassic Park to class. I showed the students a DNA sequence from the book  – a long string of A, T, C, and G that was supposed to form part of one dinosaur gene. As a class exercise, I asked students to convert that string into a protein sequence (it seems more bioinformatics teachers had the same idea).

The students were instantly intrigued. I attribute that class’ success to Jurassic Park. Both book and movie are embedded in our collective imagination. Who isn’t enthralled by the possibility of engineering dinosaur DNA and bringing the lumbering giants back to life?

Can we bring back the Tasmanian tiger? Photo by the author.

Can we bring back the Tasmanian tiger? Mike Archer at TEDx. Photo by the author.

I was able to attend the TEDx DeExtinction event in DC, thanks to an awesome boss and crew, who came along. There, molecular biologists and conservationists discussed the possibility of resurrecting extinct animals, while fans vouched for their favorite species (hello, dire wolf). The lecturers presented the technology, while ethicists and ecologists watched in horror.

The passenger pigeon is another candidate for de-extinction. Photo by the author.

The passenger pigeon is another candidate for de-extinction. Ben Novak at TEDx. Photo by the author.

There was talk of bringing back the wooly mammoth, passenger pigeon, bucardo, Tasmanian tiger and others. But like speaker and “molecular paleontologist” Beth Shapiro points out, we are still very far from step one. No surprise here. I went to this event not expecting to see a herd of mammoths any time soon. I went there to marvel at technology  and its applications. Or, like my colleague described it, “the moon race for biologists”.

Beth Shapiro is cautiously optimistic. Photo by the author.

Beth Shapiro is cautiously optimistic. Photo by the author.

Conservation efforts can benefit from de-extinction technologies. Lack of genetic diversity among captive breed populations is a serious problem. Breeding programs and SSPs (species survival plan) keep a studbook: a record of the genetic make up of all individuals of that species. Pairings are carefully calculated in order to increase genetic diversity. TEDx host Stewart Brand (check out his Reddit AMA) believes de-extinction can help with that: “de-extinction technology… can be applied immediately to help diagnose and treat genetic issues with endangered populations of living species. Viable cryopreserved DNA … can be used to reintroduce genetic variability in ‘genetic bottleneck’ situations for animals now rare and facing inbreeding problems.” And that’s not all. Cloning or iPCS (induced pluripotent stem cells) are technologies with immense potential, with applications that range from tissue engineering to livestock breeding, and perhaps even to support reproduction.

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Stewart Brand at TEDx. Photo by the author.

Funding dictates what research projects will go on and which ones will die.  And that is why I’m ok if a woolly mammoth or Jurassic Park-based creature functions as research ambassadors. Scientists depend heavily on policymakers and public support to guarantee funds for their work. It is increasingly difficult to obtain funds for basic research or anything that doesn’t have the word “cancer” or “heart disease” attached to it. Throughout my PhD I happened to work with both most of the time (design of protein inhibitors for breast cancer, and angiogenesis molecules for cardiovascular disease). I mean most of the time: when an application is not so direct or obvious (e.g., of studying the folding of a protein) we always highlight its future, potential, exciting, indirect and perhaps one day possible outcome (e.g., better understand Alzheimer’s). The woolly mammoth is the biophysicist’s cancer, and the passenger pigeon is his heart disease. I believe de-extinctioners were trying this PR approach.

Biotechnology for de-extinction. Photo by the author.

George Church explains the biotechnology behind de-extinction. Photo by the author.

But did it backfire? I saw many ecologists and ethicists disapproving of the entire thing. Are they spreading the fear? Is fear of science creeping out and reaching our scientific and (scientific-supporting) community? As Brand pointed out in his AMA, “fear has been institutionalized, not only by government but by (…) environmental groups broadcasting irrational fear of GMOs and radiation (to the detriment of genuine green goals like more wild lands and damping of climate change)”.

Very much alive (i.e. non extinct) blue hyacinth Margaret was present at the event. Photo by the author.

Very much alive (i.e. non extinct) blue hyacinth macaw Margaret was present at the event. Photo by the author.

George Mallory was a mountain climber and one of the English pioneers to Mount Everest expeditions on the 20’s. Why take on such endeavor? It was risky, challenging, and with no direct application. So, “why climb the Everest?”, he was asked.

“Because it is there.”

Sometimes it is all the motivation we need.

Dire Wolves on Ice

Ghost – a Game of Thrones dire wolf (HBO).

Game of Thrones fans, rejoice: the dire wolf is real. Here’s the bad news: the dire wolf went extinct 10.000 years ago. The enormous beasts who roamed the ice wasteland beyond The Wall are based on a real North American animal, who in turn left behind thousands of fossils. I have to admit that the dire wolf Ghost and his pack are the main reason why I continue to watch that show.

Ford in a snow quasi-wasteland.

The dire wolf is a close relative of the grey wolf and also (drum roll) of the dog. Meet my toned-down version of the dire wolf: Ford. Like Ghost, my dog also loves snowy wastelands. Ford is the only canine in a small pack of three (the two other members are human beings), where I am pack leader (or at least I like to think I am). That means Ford will obey me when I tell him not to chase that delicious squirrel or pounce on that fatty pigeon.

Ford.

Ford weighs around 60 lbs, which is about half the size of a large dire wolf. Large wolves could reach 175 lbs, and the ones featured on Game of Thrones were as big as a horse (fictional wolves don’t count: they had magical powers; the evidence of magical powers has not been found in fossils yet). If Ford was a dire wolf 10.000 years ago, he would have probably hunted on a pack with 30 other buddies, and something tells me this group would not be after squirrels or pigeons. Instead, dire wolves hunted for mammoths. 

A fantastic wall of thousands of dire wolf skulls. Photo by the Page Museum.

A wall of skulls

The Rancho de La Brea, in Los Angeles, is fossil site where thousands of prehistoric ice age animals were entrapped, their bones perfectly preserved in tar. In this tar pit, fossil bones of 3600 dire wolves were found. This is the largest amount of a predator specimens ever found in one site, and it way outnumbers all other mammals found in the same site. Saber-toothed cats are next on the list, but not nearly as numerous (“only” about 2000 are found on the tar pits). Much fewer prey animals were found, about 200 horses and 300 bison, which means there’s a ratio of ten predators to each prey.

What happened here? It seems one unlucky prey animal – say, a bison – would fall in the pit and become trapped. Right after, packs of dire wolves and saber-toothed cats would believe it an easy meal and jump in. Result: prey and predator – specifically one prey and dozens of predators – die together.

Today, the Page Museum displays finds from the tar pits (including an impressive wall of dire wolf skulls). Fossils are so numerous that the Page Museum recruits and trains volunteers to help with the ongoing excavations (volunteer finds are posted on the museum’s blog).

Dire wolf artistic depiction by Mauricio Anton.

Lions, tigers, and bears, oh my! (Or: the hunting habits of carnivore predators)

Before they went extinct, the dire wolf and the saber-toothed cat were as dominant predators as the lion and hyena are today in Africa. The high number of skeletons found on the tar pits suggested they (both dire wolves and saber-tooth) hunted in large packs and were able to tackle enormous prey – bison and camels, but also mammoths, mastodons, ground sloths, and Irish elk. Carnivores weighing more than 46lbs need to eat prey that is as large or larger than themselves. Those predators cannot survive only on small prey, because they would spend a disproportionally higher amount of energy hunting the prey than they would get by eating it. So, the efficient way to eat is to hunt for large prey. The devised strategy adopted by many carnivores is to form a pack. Grey wolves exhaust the prey, but lions or dire wolves, who are larger and more stockish, pounce and grab them.

From left to right: dire wolf, saber-toothed cat, short-faced bear, cheetah-like cat (Miracinonyx sp.), American lion. (Modified from Turner, A., and Anton, M., The Big Cats and Their Fossil Relatives. Columbia University Press: New York, 1997)

Extinction

The dire wolf’s cousin, the grey wolf, is now considered a top North American predator. But the grey only reached this post after many large carnivores went extinct. Both the grey wolf and the dire wolf co-existed with 10 other species of large carnivore: the puma, jaguar, two species of short-faced bear, florida-spectackled bear, black bear, scimitar-toothed cat, saber-toothed cat, grizzly bear, and the American lion. All 12 carnivores competed for similar prey. Most of those predators became extinct 10.000 years ago (ever wondered why there are no lions, tigers, or elephants in the US? Because they died off after climate change or food depletion). Now only the puma, black bear, and grizzly bear remain.

Compared to the grey wolf, dire wolves had shorter stouter legs and smaller brain cases. They also had stronger teeth, comparable to a hyena’s in its bone-crunching abilities (which probably means food was scarce and every bit of bone marrow was precious). Dire wolf teeth is more adapted for “carnivority”, which means they are not as versatile in eating alternatives (other carnivores, like bears, will eat even bugs and honey). All of that contributed to their demise.

Ford looks at his extinct canid relatives.

Survival of the coldest

But here’s a fact Game of Thrones did not tell us: dire wolves were creatures of warm weather! They preferred tropical or subtropical regions. One of the reasons the grey wolves survived and dire wolves didn’t is because the grey wolf’s hunting range extended to the cold arctic. During the Ice Age, the dire wolf was left behind, to die and disappear.

But I guess the appeal of a beast of the tropics does not suit Game of Thrones. Ford, for once, prefers snow and cold, and becomes very depressed on the summer. Instead of the dire wolf, Ford would have fit in perfectly in Winterfell.