Will there be mammoths at Longleat?
Will the new technologies of cloning and genetic engineering enable us to re-create the dinosaurs, as Michael Crichton foresaw in Jurassic Park? Will our children take their children to see the mammoths at Whipsnade and Longleat—or indeed in Siberia, where they roamed in vast numbers until just a few thousand years ago?
Fanciful?—Yet high-tech is already promising a quite new era of conservation. For scientists in America are now cloning one of the world's most magnificent endangered species—a gaur, the 'bison' from India which at two metres (at the shoulder!) is the tallest and to my eyes the most beautiful of cattle. The cloned bull calf is still in the womb of his surrogate mother—an ordinary domestic cow called 'Bessie'. But he's due next month.
Then, Robert Lanza and his colleagues at Advanced Cell Technology (ACT) in Massachusetts will try to clone a kind of goat that is already extinct—the bucardo, from the Spanish Pyrenees. The last known bucardo was killed by a falling tree in January of this year, but samples of its flesh have been kept in the deep-freeze and they, plus a few living she-goats, are all that should be needed to bring it back to life.
The giant panda and the Barbary lion—both hanging on to life by a whisker—are also obvious candidates. After that—who knows?
In practice it's now easy to clone animals like the gaur—or even recently-extinct creatures, like the bucardo. Scientists can simply apply the method that produced Dolly at Roslin Institute, Edinburgh, in 1996. Ian Wilmut and Keith Campbell first cultured body cells taken from the udder cells of an old ewe—cells that had been grown and multiplied in culture, and then deep-frozen. They also took fresh eggs from other sheep, and removed their nuclei, which contain the DNA, to produce 'enucleated eggs'.
Then, with the aid of a small electric shock, they fused cultured udder cells with the 'enucleated' eggs. The resulting 'reconstructions' were like one-celled embryos—except that they contained DNA from the original ewe, and hence were 'genetic clones' of that ewe. After a few days incubation, the reconstructed embryos were placed in the wombs of yet more sheep who acted as 'surrogate mothers'. Some of those embryos went through successful pregnancies—and one survived to become Dolly. Since then, many other animals of several species, including domestic cattle and mice, have been cloned in just this way. Incidentally, the ewe who donated her udder cells died some years before Dolly was made. Only her frozen tissue survived. But this was all that was needed to clone a whole new sheep.
Mammoths mostly died out around 10,000 years ago but a few small types—so-called 'dwarf' mammoths—apparently survived on the island of Wrangel to the north of Siberia until around 4,000 years ago. They were still around when the Pharoahs ruled Egypt. Many a modern wolf and not a few human explorers have dined on mammoth flesh, still frozen in the permafrost. If it's good enough to barbecue, might it be cultured—and cloned?
Perhaps. But crystals of ice form when tissue is frozen, and cut the cells like razors. The cells that provided Dolly's genes were cultured before freezing to form thin, easily cooled layers, and were then frozen in conditions minutely controlled to prevent crystals forming. But mammoths just froze where they fell—the flesh cooling slowly and unevenly. The thawed flesh may be edible, but the cell damage must be horrendous.
It will need luck to find mammoth tissue good enough to culture and so to clone. If suitable cells are found, it should be possible to fuse them with modern elephant eggs. But they would then have to be placed in the womb of a surrogate elephant mother—and so far, embryo transfer has not succeeded in elephants. High tech is all very exciting—but first we must solve the obstetric problems.
Dinosaurs are a different ball-park all together. The last ones died out around 65 million years ago, and no-one expects to find entire cells. At best we might find the odd scrap of DNA—but claims that DNA has already been found in the bellies of blood-sucking insects trapped in amber, are all disputed. Even if we did find fragments, and we would have to fill in the missing bits with DNA borrowed from living creatures such as crocodiles (as in Jurassic Park)—or, more likely, from birds, which are even more closely related. But it's one thing to clone an animal from entire cells, like Dolly and the new gaur. It's another entirely to make a whole animal from isolated DNA. If we also had to add the missing bits then at best we would make a dinosaur mock-up—like the re-constructed Greek and Minoan temples that archaeologists liked to piece together in the 19th century.
I hope we can re-create mammoths. I feel cheated that they are no longer with us. They almost made it into modern times—and would have, for sure, if our ancestors had not killed them off. To restore them would be a kind of atonement.
But to restore the dinosaurs, assuming we could, seems to me to be almost evil: science without restraint; science as pornography. The beasts themselves would be unhappy re-inventions—for we cannot possibly guess in detail what they were really like. More to the point, their world has gone: the swamps, the endless warm shallows, the vast forests of 'seed ferns' and other weird and wonderful plants that have no modern equivalents. The mammoths belong to our times, and should be with us still. The dinosaurs do not. Conservation is largely a matter of aesthetics—as, indeed, all science and technology should be. Intuition tells us where to draw the line.
But the potential of cloning to save the many hundreds of existing creatures that are now endangered is enormous. Of course the ideal is to save their habitats—but sometimes the wild is already too desecrated and we need to rescue the beasts and restore their environments before we put them back. Most of them breed well enough in captivity but the problem is to maintain their diversity—for if they are kept only in small numbers, as is inevitably the case, they lose their genetic variety.
So right now, as a matter of urgency, we should be taking tissue samples from all the animals we can lay hands on (which can be done without hurting them!), culturing their cells, and putting them in the freezer. Then the conservation scientists of 50 or 100 years' time will be able to clone new creatures from them, just as Dr Lanza and his ACT colleagues are now cloning gaur. With cloning technology, in short, we could immediately save all the genetic diversity of all the large animals on Earth, and thus solve one of conservation's greatest problems at a stroke.
So I don't want to see dinosaurs in the flesh. I am content to do without mammoths, sad though this is. But I dearly want my grandchildren to see the beasts that I used to take for granted—tigers, elephants, ocelots, parrots, what you will. If we just let things drift, their chances seem thin. But with can-do energy—and a little modern ingenuity—we really can give them a fighting chance. It's good to see high tech used for such aesthetic ends.
Colin Tudge discusses these issues further in Last Animals at the Zoo (Oxford University Press, 1992), The Variety of Life (OUP, 2000) and In Mendel's Footnotes (Jonathan Cape, 2000).