HOW TO CLONE A MAMMOTH
The Science of De-Extinction
Book review by Anthony Campbell. The review is licensed under a Creative Commons Licence.
Before reading this book I had not taken much interest in the possibility of reviving extinct species ("de-extinction"), supposing that it was largely confined to the realms of fiction like Jurassic Park, but this excellently written book has convinced me that I was wrong. Beth Shapiro explains, with admirable clarity and humour, why de-extinction matters and where the boundary lies between science and fiction. She is well placed to do this, heing professionally involved in the extraction of DNA from ancient bones for use in genetic engineering.
In fact, most of the speculation that appears in the media is fiction. De-extinction, if it is possible at all, is going to be a lot harder to achieve than you might think. (For a start, it is impossible to clone birds, so reviving the dodo is out.)
A popular scenario consists in obtaining the genome of an extinct animal such as a mammoth, using it to replace the nucleus of an egg from a suitable donor such as an elephant, and inserting it into the uterus of the elephant to develop into a mammoth. This sounds fine until you start to think about it in detail, when numerous all but insuperable difficulties appear.
For a start, where does the genomic material come from? Frozen mammoth carcases frequently pop up in Siberia, but unfortunately the DNA in their soft tissues is never preserved. Mammoth bones are a better bet, but even here only short fragments can be extracted and the process of assembling these into a viable genome is challenging in the extreme. Obtaining elephant eggs is also difficult. And even if all those problems could be solved, there would still remain the requirement to persuade the new genome to revert to embryonic status so as to produce an actual mammoth.
For these and many other reasons Jurassic Park-style cloning will almost certainly never happen. That doesn't mean that de-extinction in a modified form is out of the question. Instead of trying to recreate a complete species, we could engineer genomes that contain some of the features of extinct organisms. For example, we could produce an elephant that had long hair like a mammoth and had other features of cold adaptation that the mammoth possessed. This creature could then perhaps be introduced into a cold environment such as Siberia. This would not be reviving the mammoth, it would be producing an engineered elephant with some mammoth-like features.
Of course, it would be useless to place just one pseudo-mammoth in Siberia; we would need a breeding population, and that poses many new problems. Producing just one engineered elephant would be a major undertaking, never mind a herd of them. It also raises ethical, economic, ecological, and even legal questions. Shapiro discusses these in some detail.
Shapiro's own work has been concerned both with mammoths and with the extinct passenger pigeon, which used to flock in vast numbers across North America until fairly recently. It would probably be possible to use the band-tailed pigeon, which is closely related to the passenger pigeon, as a basis for de-extinction. But what then? Would the newly released "passenger pigeons" flock automatically as the original species did, or would they have to be trained to do so, perhaps by using homing pigeons as surrogate "instructors"? And even if that were possible, would it be desirable? The original passenger pigeons behaved rather like a swarm of locusts, stripping bare the fruit trees in their path. Would we want that today? And are there still enough of the right kinds of tree to support them?
In spite of all her reservations, Shapiro believes that the work she and others are doing to make some form of de-extinction possible is important and and provides hope for the future.
This, I believe, is why people like me are so captivated by the idea of de-extinction. Not because it is a means to turn back the clock and somehow right our ancestors' wrongs, but because de-extinction uses awesome, exciting, cutting-edge technology to take a giant step forward. De-extinction is a process that allows us to actively create a future that is really better than today,not just one that is less bad than what we anticipate. It is not important that we cannot bring back a creature that is 100 percent mammoth or 100 percent passenger pigeon. What matters is that—today—we can tweak an elephant cell so that it expresses a mammoth gene. In a few years those mammoth genes may be making proteins in living elephants, and the elephants made up of those cells might as a consequence no longer be isolated to pockets of declining habitat in tropical zones of the Old World … De-extinction is a markedly different approach to planning for and coping with future environmental change than any other strategy that we, as a society, have devised. It will reframe our possibilities.Reading this book has convinced me that de-extinction matters. We are constantly hearing that we are causing the sixth great extinction. Perhaps this is one way that we could start to reverse the trend.
%T How to Clone a Mammoth
%S The Science of De-Extinction
%A Beth Shapiro
%I Princeton University Press
%C Princeton and Oxford
%G ISBN 9780691157054jj
%O colour plates
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