Matt Ridley: Reversing Extinction Is A Mammoth Task

The revival of a frozen Siberian flower paves the way for other species to return.

The fruit of a narrow-leaved campion, buried in permafrost by a ground squirrel 32,000 years ago on the banks of the Kolyma river in Siberia, has been coaxed into growing into a new plant, which then successfully set seed itself in a Moscow laboratory. Although this plant species was not extinct, inch by inch scientists seem to be closing in on the outrageous goal of bringing a species back from the dead. I don’t expect to live to see a herd of resurrected mammoths roaming the Siberian steppe, but I think my grandchildren just might.

The mammoth is the best candidate for resurrection mainly because flash-frozen ones with well-preserved tissues are regularly found in the Siberian permafrost. Occasionally these have been fresh enough to tempt scientists to cook and eat them, usually with disappointing results. Just last week a Chinese paleontologist in Canada, Xing Lida, filmed himself frying and eating what he said was a small mammoth steak. Cells from such carcasses have been recovered, encouraging a rivalry between Japanese and Russian scientists to be the first to revive one of these huge, elephant-like mammals by cloning. Four years ago the mammoth genome was sequenced, so we at least now know the genetic recipe.

The news of the resurrected flower does, apparently, remove one obstacle. After 32,000 years the plant’s DNA had not been so damaged by natural radioactivity in the soil as to make it unviable, which is a surprise. Mammoth carcasses are often much younger – the youngest, on Wrangel Island, being about 4,700 years old, contemporary with the Pharoahs. So the DNA should be in even better shape.

However, plants are much better at cloning themselves from any old cutting. Coaxing an elephant cell into becoming an embryo is not at all easy; though, as Dolly the sheep showed, not impossible. To do the same for a mammoth cell would be harder still. And then there is the problem of how to get the embryo to grow. Implanting it into the womb of an Indian elephant (its closest living relative) is the best bet, but experiments with implanting rare embryos into other species’ wombs have been mostly unsuccessful. For example, a rare form of wild ox, the gaur, was going to have its embryos reared in cattle wombs, but it did not work.

So do not book the Siberian mammoth safari trip just yet. Equally, don’t bet against it eventually coming off. Which other species might follow? One that only recently went extinct (last seen in 1936) is the marsupial carnivore called the thylacine, or “Tasmanian tiger”. A few years ago, genes from a dead thylacine were injected into a mouse and “expressed” in its tissue. The great auk, the dodo and other creatures that died out before the invention of refrigeration are going to be much harder to revive. Perhaps fortunately, Neanderthals, dead for 28,000 years, unfrozen and not very closely related to their likely surrogate parent (you and me), would be harder still, though their DNA sequence is now known. And as for the dinosaurs – 65 million years dead – forget it. Although come to think of it, re-engineering a chicken until it looks like a dinosaur cannot be ruled out, once people learn to play genetics well enough.

The real significance of the Siberian flower, though, is that it makes future extinctions potentially reversible. So long as we can flash-freeze seeds and tissues from threatened species (a disused mine in a frozen mountain in Spitsbergen already holds a seedbank of rare plant varieties), then we can give posterity the chance to resurrect them. Combine this with the news that extinction rates, at least of birds and mammals, have been falling in recent decades, and there are grounds for a glimmer of ecological optimism. The great spasm of extinction caused by humans – mainly when we spread our rats, weeds and bugs to oceanic islands – may be coming to an end.

GWPF