De-Extinction in 10 (Not So Easy) Steps

Illustration of Extinct Woolly Mammoth
Getty Images/Elena Duvernay/Stocktrek Images

 Everyone these days seems to be talking about de-extinction—a proposed scientific program to "re-breed" species that have been extinct for hundreds or thousands of years—but there's surprisingly little information about what, exactly, is involved in this Frankenstein-like endeavor. As you can easily see from perusing the 10 following steps, de-extinction is more of an aspiration than a reality—depending on the pace of scientific progress, we may witness a fully de-extincted species in five years, 50 years, or never. For the sake of simplicity, we've focused on one of the most likely candidates for de-extinction, the Woolly Mammoth, which vanished off the face of the earth about 10,000 years ago but has left behind numerous fossil specimens.

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Obtain Funding

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In the past few years, industrialized nations have earmarked an impressive amount of money for environmental initiatives, and non-governmental organizations, too, have cash at their disposal. But the best prospect for a team of scientists wishing to de-extinct the Woolly Mammoth would be to obtain funding from a government agency, the go-to source for university-level research projects (major backers in the U.S. include the National Science Foundation and the National Institutes of Health). As difficult as obtaining a grant can be, it's even more of a challenge for de-extinction researchers, who have to justify resurrecting an extinct species when it can be argued that a better use for the money would be to prevent endangered species from vanishing in the first place. (Yes, the project can conceivably be funded by an eccentric billionaire, but that happens more often in the movies than it does in real life.)
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Identify a Candidate Species

woolly mammoth
The Woolly Mammoth. Wikimedia Commons

This is the part of the de-extinction process that everyone likes best: choosing the candidate species. Some animals are "sexier" than others (who wouldn't want to resurrect the Dodo Bird or the Saber-Tooth Tiger, rather than the less-headline-worthy Caribbean Monk Seal or Ivory-Billed Woodpecker?), but many of these species will be excluded by inflexible scientific constraints, as detailed later on in this list. As a general rule, researchers either prefer to "start small" (with the recently extinct Pyrenean Ibex, for example, or the tiny and malleable Gastric-Brooding Frog), or swing for the fences by announcing plans to de-extinct the Tasmanian Tiger or the Elephant Bird. For our purposes, the Woolly Mammoth is a good compromise candidate: it's huge, has excellent name recognition, and cannot be immediately ruled out by scientific considerations. Onward!

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Identify a Close Living Relative

african elephant
The African Elephant. Wikimedia Commons

Science is not yet—and probably never will be—at the point where a genetically engineered fetus can be incubated entirely in a test-tube or other artificial environment. Early on in the de-extinction process, a zygote or stem cell needs to be implanted in a living womb, where it can be carried to term and birthed by a surrogate mother. In the case of the Woolly Mammoth, the African Elephant would be the perfect candidate: these two pachyderms are roughly the same size and already share the bulk of their genetic material. (This, by the way, is one reason the Dodo Bird wouldn't make a good candidate for de-extinction; this 50-pound fluffball evolved from pigeons that made their way to the Indian Ocean island of Mauritius thousands of years ago, and there aren't any 50-pound pigeon relatives alive today that would be capable of hatching a Dodo Bird egg!)

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Recover Soft Tissues from Preserved Specimens

woolly mammoth
A mummified Woolly Mammoth. Wikimedia Commons

Here's where we start getting to the nitty-gritty of the de-extinction process. In order to have any hope of cloning or genetically engineering an extinct species, we need to recover copious amounts of intact genetic material—and the only place to find copious amounts of intact genetic material is in soft tissues, NOT in bone. This is why most de-extinction initiatives focus on animals that have gone extinct in the last few hundred years, since it's possible to obtain segments of DNA from the hair, skin and feathers of preserved museum specimens. In the case of the Woolly Mammoth, the circumstances of this pachyderm's death offer hope for its prospects of life: dozens of Woolly Mammoths have been found encased in Siberian permafrost, a 10,000-year deep freeze that aids in the preservation of soft tissues and genetic material.

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Extract Viable Segments of DNA

Wikimedia Commons

DNA, the genetic blueprint of all life, is a surprisingly delicate molecule that starts degrading immediately after an organism's death. For this reason, it would be exceedingly improbable (verging on impossible) for scientists to recover a completely intact Woolly Mammoth genome consisting of millions of base pairs; rather, they would have to settle for random stretches of intact DNA, which may or may not contain functioning genes. The good news here is that DNA recovery and replication technology is improving at an exponential rate, and our knowledge of how genes are constructed is also continually improving—so it may be possible to "fill in the gaps" of a badly damaged Woolly Mammoth gene and restore it to functionality. It's not quite the same as having a complete Mammuthus primigenius genome in hand, but it's the best we can hope for.

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Create a Hybrid Genome

Wikimedia Commons

Okay, things are starting to get tough now. Since there's virtually no chance of recovering intact Woolly Mammoth DNA, scientists will have no choice but to engineer a hybrid genome, most likely by combining specific Woolly Mammoth genes with the genes of a living elephant. (Presumably, by comparing the genome of an African Elephant to the genes recovered from Woolly Mammoth specimens, we can identify the genetic sequences that code for "mammothness" and insert them in the appropriate places.) If this sounds like a stretch, there is another, less controversial route to de-extinction, albeit one that wouldn't work for the Woolly Mammoth: identify the primitive genes in an existing population of domesticated animals, and breed these creatures back into something approximating their wild forebears (a program that is currently being implemented on cattle, in an attempt to resurrect the Auroch).

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Engineer and Implant a Living Cell

Wikimedia Commons
Remember Dolly the sheep? Back in 1996, she was the first animal ever to be cloned from a genetically engineered cell (and to show how involved this process is, Dolly technically had three mothers: the sheep that provided the egg, the sheep that provided the DNA, and the sheep that actually carried the implanted fetus to term). As we proceed with our de-extinction project, the hybrid Woolly Mammoth genome created in Step 6 is implanted into an elephant cell (either a somatic cell, e.g. a specialized skin or internal organ cell, or a less differentiated stem cell), and after it has divided a few times the zygote is implanted into a female host. This last part is easier said than done: an animal's immune system is exquisitely sensitive to what it senses as "foreign" organisms, and sophisticated techniques will be required to prevent an immediate miscarriage. One idea: raise a female elephant that has been genetically engineered to be more tolerant of implantation!
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Raise the Genetically Engineered Offspring

There is light—literally—at the end of the tunnel. Let's say our African Elephant female has carried its genetically engineered Woolly Mammoth fetus to term, and a shaggy, bright-eyed baby is successfully delivered, generating headlines worldwide. What happens now? The truth is that no one has any idea: the African Elephant mother may bond with the child as if it were her own, or she may equally well take one sniff, realize that her baby is "different," and abandon it then and there. In the latter case, it will be up to the de-extinction researchers to raise the Woolly Mammoth--but since we know virtually nothing about how baby Mammoths were raised and socialized, the child may fail to thrive. Ideally, scientists would arrange for four or five baby Mammoths to be born around the same time, and this new generation of very old elephants would bond among themselves and form a community (and if that strikes you as both a very expensive and a very doubtful prospect, you're not alone).

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Release the De-Extincted Species into the Wild

Heinrich Harder
Let's assume the best-case scenario, that multiple Woolly Mammoth babies have been brought to term from multiple surrogate mothers, resulting in a nascent herd of five or six individuals (of both sexes). One imagines that these juvenile Mammoths would spend their formative months or years in a suitable enclosure, under the close watch of scientists, but at some point the de-extinction program will be taken to its logical conclusion and the mammoths will be released into the wild. Where? Since Woolly Mammoths prospered in frigid environments, eastern Russia or the northern plains of the U.S. might be suitable candidates (though one wonders how a typical Minnesota farmer will react when a stray mammoth crumples his tractor). And remember, Woolly Mammoths, like modern elephants, need a lot of space: if the goal is to de-extinct the species, there's no point in restricting the herd to 100 acres of pasture and not allowing its members to breed.
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Cross Your Fingers

Scotch Macaskill

We've gotten this far; can't we call our de-extinction program a success? Not yet, unless we're absolutely certain that history won't repeat itself, and the circumstances that led to the extinction of the Woolly Mammoth 10,000 years ago won't be inadvertently duplicated by well-meaning scientists. Will there be enough food for the Woolly Mammoth herd to eat? Will the Mammoths be protected from the depredations of human hunters, who will likely flout even the most punitive regulations for the chance to sell a six-foot tusk on the black market? What impact will the Mammoths have on the flora and fauna of their new ecosystem—will they wind up driving other, smaller herbivores into extinction? Will they succumb to parasites and diseases that didn't exist during the Pleistocene epoch? Will they thrive beyond anyone's expectations, leading to calls for a culling of the Mammoth herd and a moratorium on future de-extinction efforts? We don't know; know one knows. And that's what makes de-extinction such a thrilling, and frightening, proposition.