Resurrecting extinct animals

Ross MacPhee is curator at the Department of Mammalogy at the American Museum of Natural History in New York. His research areas include paleobiography as well as the emergence and spread of species and their extinction. He has worked on questions relating to the mammalian and vertebrate diversity of the Caribbean Islands, Madagascar and Antarctica across time periods from late Mesozic to Neogene.

Global Ideas: One of your research areas include woolly mammoths, the last of which died around 4,000 years ago. How likely is it they can be resurrected with the help of modern science?

I would rate the probability somewhere between the range of 20 and 30 percent. With mammoths in particular, you have a very close relative with the Asian elephant. Where you have to work in order to make an Asian elephant into a mammoth, would be the kinds of genes that are responsible for hair growth since Asian elephants are basically naked. You would have to work with fat deposition and you’d have to do something about those tusks curling over.

Are you drawn to the idea?

It would be fascinating to see something that looked like the mammoth again. But, I would be very worried about the life of that animal.

Why is that?

What would we do with a herd of mammoths? Where would we keep it? Its original ecosystem, the Tundra, is now not the way that it was when mammoths were living there. They would all die. If you want mammoths to survive in a place where they are likely to do alright, then the great plains of the US would be fine. However they happen to have very large cities and very extensive highway systems. You could not possibly have animals of this size in a condition like that. They would be a threat both to themselves and to the human population. So why bring things back that don’t have a perceptible role any more?

Advocates would say that you could keep such large animals in a zoo.

Animals have rights too and we as knowledgeable humans should provide for them. If we don’t do that, we’ll just be creating a freak show. To me, that is neither appropriate nor ethically desirable. So, you would end up bringing these extinct animals back to life. But you would just be giving them a sort of a faux live in which they merely exist as a bunch of individuals without ensuring that they can reoccupy nature in the way they did when they were alive.

Yet, scientists are focusing more than ever on bringing extinct species back to life. What pre-requisites are needed for that?

You need to get a sufficiently large amount of genetic information of the extinct species from bones or tissue. Then you compare that information to that of the living species and figure out what’s the same and what’s different. You try and balance out different or missing information through so-called “synthetic biology”. Over time and with lots of effort, you can manufacture a genome which is in the high 90 percentile of resemblance of that of the extinct species. This DNA is then inserted into an embryo of a related species. Once the offspring is born, it looks like the modern living species from the outside. But it carries in it the DNA of the vanished species so that in the next generations, you have an animal that could produce something that will look like the species that died out many years ago.

When do you think we will see actually see an extinct species being resurrected?

Well, research on the passenger pigeon is the most advanced so far. I am sure they will bring back the passenger pigeon in one to five years. The bird went extinct towards the beginning of the 20th century and we have several hundred samples of genetic material collected around the end of the 19th century. I am sure we will see something that is going to phenotypically look like a passenger pigeon in about five years.

Would it not be the same animal?

Scientists will have gone through all kinds of trouble to match up genetic sequences with what we know from passenger pigeons with modern band-tailed pigeons. But it still will not be exactly the same. The resulting animal will only be a hybrid. We will not be able to reproduce these vanished species a 100 percent, more like 95 percent. It’s not the same as going back in a time machine and grabbing that animal and bringing it back to the present.

Why is the subject of “de-extinction” being debated so intensely right now in the scientific community?

In recent years, there have been big advances in the work with “ancientDNA“, which means DNA that is at least a 100 years old. In other words, taking a piece of bone or tissue, extracting material including genetic components, identifying that material, comparing it to the ones of its close living relatives and replacing it. With synthetic biology, scientists now can change elements that make up the genetic code. Over time, they can manufacture the organism from its most elemental level up to the adult.

Doesn’t that excite you as a scientist?

I am not uniformly against it. But de-extinction is an antiquarian effort, very few people are interested in bringing back a mammoth. What’s more important is the capacity to create life that has never existed before. And I think it requires that people have an educated understanding of the potential because there are many positive things about synthetic biology as well as the possibilities of misuse. Scientists can absolutely change the ecology of the planet. So we need to talk it out.

There could be laws that could limit that.

Then you don’t know humans. That’s because somewhere somebody is probably already trying it. In fact, in both Korea and Japan there have been efforts for more than a decade to both find viable cells of mammoths out in the Siberian Tundra and work with them in various complex ways see to if you can trigger them into life. But the bigger story is not going to be the mammoth in your backyard. The big story is how synthetic biology changes life for all of us by being able to manipulate nature, manipulate species and genetic information at levels we could not have possibly imagined short of ten years ago. In my opinion, it is important to stay at hand and not go the distance unless you have worked out the details of where, how and what.