“What’s the point of bringing back some pigeons that have been gone for a century, or some hairy elephants that disappeared four millennia ago? Well, what’s the point of protecting unhairy elephants in Africa or over-specialized pandas in China or dangerous polar bears in the Arctic, or any of the endangered species we spend so much money and angst on preserving?”
– Stewart Brand
It’s difficult to argue with that logic. In 2012, the US spent over $3 billion on conservation efforts.
I don’t know about you, but I always dreamt of a real-life Jurassic Park. Unfortunately, it doesn’t seem like dinosaurs will ever have the chance to roam the Earth again. Quite frankly, with new research showing that most dinosaurs probably had feathers, I’m not sure it would even live up to what our minds are conditioned to believe dinosaurs to look like anyway. They’d be giant, carnivorous chickens, more or less. But what about a mammoth or a thylacine?
While the DNA that once inhabited a dinosaur bone is long gone, victim to over 65 million years of radiation, hydrolysis, and other forms of degradation, DNA can be found in some more recent specimens. But how would it work? How could we possibly bring back – that is, De-Extinct – an organism. Well, actually, it’s already been done.
The Sad Saga of the Pyrenean Ibex
The last surviving Pyrenean Ibex died in 2000. Of all the ways for a species to go out, this one was found dead underneath a fallen tree. It seems as though Mother Nature was just out to get them. So, naturally, humans did what humans do best – try to one-up Mother Nature. Pre-emptively thinking in 1999, biologists cryogenically froze a tissue sample of Celia, the last surviving member of her species. When Celia died, scientists were ready to bring her back.
The technique used is called somatic cell nuclear transfer. You can find a short video of it happening in real time here. Essentially, an oocyte – egg cell – from a domestic goat was de-nucleated and the nucleus from one of Celia’s somatic (body) cells was inserted into the empty oocyte. The resulting cells were then transferred into a domestic goat surrogate. Unfortunately, the process proved technically difficult. 285 embryos were reconstructed. Of those, 54 were transferred to 12 ibex and ibex-goat hybrids. Only two survived the two months of gestation before they too died. One clone was finally birthed in 2009 – the very first de-extinction. Unfortunately, the clone had a lung defect, and died of a collapsed lung only 7 minutes after birth. One of the problems was likely the fact that Celia was already 13 years old – old age for a goat – when the tissue sample was taken. This means that her telomeres, the caps on chromosomes that protect the supercoiled DNA, were already very short. As DNA replicates, the enzymes cannot make it to the very end of the DNA (where the telomeres are located), so the telomeres are truncated. They act as a sort of buffering system to keep the actual genes from being damaged (on a side note, your age is essentially a function of your telomere length).
The procedure seemed to doom any idea of de-extinction. After all, if we can’t even bring back a species that has been dead for under a decade, how can we ever hope to bring back a 30,000 year-old wooly mammoth? Fortunately, scientists are incredibly stubborn, and didn’t just drop the idea all at once. With advances in technology, science fiction often becomes reality. In the field of de-extinction, the limiting factor is DNA extraction and sequencing technology, which seems to be growing faster than Moore’s Law predicts it should.
A New Method
So, is there another way – a better way – to clone an animal than by somatic cell nuclear transfer? Maybe, and it’s called induced-pluripotent stem cell (IPS)-Derived sperm and egg cloning. The idea behind this is to splice your target species DNA (say, from a mammoth) into a surrogate stem cell genome (say, from an Asian elephant). Because these are stem cells (or pluripotent cells), they can become anything. So you coax the newly modified stem cells into becoming germ cells – those that will make the testes and ovaries. You then insert the germ cells into the embryos of a male and female surrogate (Asian elephants, in our example). Now you have a male and female Asian elephant embryo with mammoth precursory germ cells. You grow up the two surrogates, and they will exhibit target species (mammoth) gonads (testes and ovaries). So, you then mate the two and out comes a “full-blood” mammoth (click here and skip ahead to about the 10 minute mark to see this example with falcons and chickens. I recommend watching the entire TED talk. It’s my favorite one, and will explain a lot about De-Extinction).
You will see a second De-Extinction in your lifetime, and hopefully more to follow. Expect it from – Passenger Pigeons, Gastric Brooding Frogs, and, hopefully, Mammoths.
Maybe We Can… But Should We?
This, to me, is one of the biggest hurdles. You have to convince people that something, at least of this caliber, is a good idea. I began the post with a quote from Stewart Brand that I think idealizes the argument for De-Extinction. Hank Greely, a Stanford Law School professor specializing in biomedical technology ethics gives an excellent TED talk on this (found here). To outline his talk, here are the 10 things we must consider, 5 risks and 5 benefits:
- Animal Welfare
- Political Concerns
- Scientific Knowledge
- Technological Progress
I will flesh these out quickly, but won’t spoil the TED talk.
- Cloning isn’t a very “safe” process. It can take hundreds of embryos, and often the few who survive don’t last long. We need to ensure the welfare of the animals that we try to bring back.
- What if we bring back an animal and it happens to be a great vector for a terrible disease? Oftentimes the beginning of an epidemic is a new, better vector.
- If we bring back a species, is it going to cause ecological problems?
- If we make De-Extinction a plausible conservation effort, will it undermine current efforts to preserve what we have? Why try to save them if we can just bring them back? Similarly, is it worth it financially?
- To be short, we are playing God. We are doing something that, presumably, has never really happened in almost 4 billion years of life. We are redrawing the branches of the tree of life. It’s not something to be taken lightly
- We could learn things previously unknowable about genetics, evolution, and biology.
- De-Extinction is the edge of science. It is pushing technology to its outer bounds, making technological development increase faster than it normally would. This provides technological offshoots for many medical procedures.
- Bringing back a species can actually be good for the community. See, for example, the effect of wolf reintroduction at Yellowstone.
- Are reparations due? Its arguable whether or not we caused megafaunal extinction – mammoths, wooly rhinoceros, cave bear, etc. – but there’s no doubt that some species, such as the passenger pigeon, went extinct due to human activity, namely hunting. And, sadly, we continue this destructive path, which is stripping the Earth of some of its most precious large mammals – tigers, elephants, and rhinoceroses, just to name a few.
- My favorite. This is what science does. It inspires us. It awes us. It brings our imagination outside of our minds and places in front of us. Wonder isn’t all that impractical either. Wonder is what drives scientific knowledge further. It’s a self-perpetuating field that is snowballing into the ever-decreasing realm of science fiction.
The “can we” of De-Extinction is coming to a close. It’s time to start discussing the “should we” aspect. The technology will be here very soon, but are we ready?