Simply put, de-extinction is the growing field of biology that aims to bring animals back
from extinction. Genetics, molecular biology, palaeontology, and evolutionary biology intersect here to bring to life what was once considered to be a fantasy. Animals like the dodo bird, the passenger pigeon, and the woolly mammoth have all been considered as contenders for revival. Success stories, however, are harder to come by. At a presentation given at UCD last month, UC Santa Cruz researcher, Dr. Beth Shapiro posed the question “how do we bring a mammoth back to life?”, which she succinctly answered with “well, we can’t”. Not yet anyways.
Bringing the woolly mammoth back to life would involve using the established mammalian cloning protocol. Mammalian cloning, also called somatic cell nuclear transfer, involves three
rganisms. You start with DNA from the animal you want to clone; an extinct woolly mammoth in this case. Then you take an embryo from a second animal. In this case it would probably be an Asian elephant embryo. You remove the genetic material from that elephant embryo and insert the DNA from the woolly mammoth into the now empty embryo. Finally, the elephant-mammoth hybrid embryo would be inserted into the womb of a surrogate elephant who would theoretically carry this mammoth embryo to term.
The problems with this idea begin at the first step. Suitable woolly mammoth DNA needs to be taken from a living woolly mammoth cell. Despite numerous expeditions, and a close call in Siberia, no such cells have been found. The same issue is raised for most extinct animals, barring the ones that have been preserved intentionally. An example of this latter kind is the white rhino. While a few of members of the species are still alive, they are ‘functionally extinct’ because there is no viable breeding pair. What this means is that we have plenty of DNA and knowledge of the white rhino’s behaviour that we can use when de-extinction becomes a practical option.
There is a theoretical solution to this problem. A scientist could take the closest living species to the extinct one – an Asian elephant in the example of the woolly mammoth – and edit it to a point that it looks like, acts like, and is genetically identical to the extinct species. This, however, presents a host of new roadblocks. Primarily, it assumes a flawless understanding of the genes in both the extinct and non-extinct relatives. We are not there yet, and an attempt to make elephants ‘woolly’, could result in any number of mishaps. Additionally, this would not technically be de-extinction; we would be creating mammoth-elephant hybrids.
What if we could solve these problems though? What if we could perfectly recreate the woolly mammoth, or the dodo bird, or the passenger pigeon? Does it follow that we should?
While allowances might be made for the dodo or the passenger pigeon, are there ethically sound reasons for bringing back the woolly mammoth? To start, they are, well, mammoth in size. Their re-introduction to Earth would serve to be a massive disruption in an already tumultuous ecosystem. Their native terrain, and predators have all dramatically changed since the beginning of the ice age that contributed to their extinction. What’s more, elephant families would need to act as more than gestational surrogates. They would need to provide continuous social support to the de-extinct mammoths.
The idea of de-extinction is a fascinating one. Its novelty ignited a multi-billion-dollar film franchise. The sad fact is that its importance is growing. The strategies that are being directed at bringing back ancient animals that went extinct due to natural planetary cycles should instead be directed at the animals that we are pushing towards extinction. While there may be an ethical obligation to avoid the revival of woolly mammoths, there is a converse ethical obligation to restore the animals whose extinction we are responsible for. And for those animals whose numbers are now dwindling because of our degradation of the planet, we have a responsibility to use these molecular biology protocols to maintain endangered populations. Of course, that is in tandem with changing behaviours that drove them to endangerment and extinction in the first place.
Finally, it is important to note that the fears that have been associated with de-extinction because of the Jurassic Park series are simply not well-founded. The only chance that scientists have at bringing back extinct animals depends on genetic material that has been preserved for a maximum of about a million years. The dinosaurs of the Jurassic period went extinct about 65 million years ago. There is, without hyperbole, no way that DNA from any of the film’s dinosaurs could be preserved well enough to isolate, much less clone or edit. While it may sound like scary sci-fi, de-extinction may prove to be an important tool for halting or even reversing the massive biodiversity loss that we are currently causing.
Vanessa Gomes – Science Writer