Once upon a time in South Africa, there lived a curious zebra that only had half its stripes. It was called the Quagga, and the Dutch and British colonialists didn’t know quite what to make of it, for it only had stripes on the front half of its body, and those stripes were so variable in their waviness that naturalists couldn’t be sure if there was only one species, or many. While the scientists pondered this question, the hunters kindly answered for it for them by blasting the quagga into extinction. Now there were no species!
Then, in 1971, a South African naturalist named Reinhold Rau, following a challenge proposed by German biologist Lutz Heck, decided to try to bring back the quagga, even though the last one had died in a zoo in 1840. After all, what is a quagga but a zebra with a plain brown butt? DNA analysis of quagga remains in 1980 further encouraged Rau: it turned out that the quagga was not its own species, but a sub-species of Plains Zebras. Rau embarked on his mad mission, visiting the world’s zoos and selecting Plains Zebras to breed. Finally, in 2005, a foal named Henry was born with the trademark quagga quirks. Party up front, business in the back. But Henry presented a new conundrum: if it walks like a quagga, and eats like a quagga, and is striped like a quagga, is it a quagga? Is it possible to recreate natural selection through artificial selection? Can you bring an extinct species back from the dead? Well, the quagga isn’t the first animal we’ve tried to put back together from missing pieces.
The concept of “back-breeding” was introduced in the early 20th century by two German biologist brothers, Lutz and Heinz Heck. Their subjects were not zebroids but horses and cows. It’s hard for some people to imagine that horses or cattle were ever anything but farm animals, but the wild ancestor of modern cattle, the Aurochs, roamed free in Europe until the 1600’s, and the last Tarpan, or Eurasian wild horse, died only 100 years ago.
What do you think those cavemen of Lascaux were hunting? Reminders of the aurochs are everywhere, from the long, forward-pointing horns and tall hump of the constellation Taurus to the flags and coat of arms of many European cities and states, such as Moldavia. Its name is Germanic for “Ur-Ox,” the original ox. Everything the modern cow has been bred to be — complacent, stupid, gentle — had to be bred out of its huge, proud, bad-tempered ancestor, the aurochs. In the end, the aurochs’ size (it weighed over a ton) and fierce disposition were its undoing. It was considered such delightfully dangerous quarry that it was hunted into extinction in 1620, the last one a female shot in the forests of Poland.
These wolves’ first mistake was calling him a “cow.”
Similarly, the tarpan couldn’t be hitched to the plow. The stocky wild ancestor of the horse ranged from Spain to Russia, running unbridled in the mountains and steppes, away from the horses who had been domesticated from their stock 3,000 years ago. Because it couldn’t be saddled, it was considered a game animal.
The last wild tarpan was spotted hiding out in a plateau in Ukraine; it was chased off a cliff into a crevasse. The last tarpan of all died in a Russian zoo in 1909, with a bit in its mouth. Europe itself had become domesticated, and was purging itself of its last wild and willful animals. It was a horse’s world.
Then along came the brothers Heck, two zoo directors with a dream. This vision was a little more legit than simply painting stripes on a donkey and calling it a quagga. Their reasoning was that, if cows and horses are the descendants of aurochs and tarpans, the genetic code for those animals was still available, just repressed. The sum of all the world’s breeds of cattle was the aurochs. It made some sort of sense; after all, wild dogs, when allowed to interbreed freely into mutts and mongrels, eventually become wolf-like, and feral pigs will revert to a boar-like state after only a few generations. So Lutz Heck, working in his laboratory in Berlin, and Heinz, working separately from Munich, began a process of breeding cattle that displayed the traits of the lost aurochs. A dash of Scottish highland cattle for burliness here, a pinch of Hungarian grey cattle for horn size there, etc. Stir until well-blended. Naturally, the Nazi party loved the idea of a wild, strong, prototypically Aryan bull, so while the aurochs project was originally apolitical, the brothers Heck happily took Nazi grant money. (In fact, Lutz Heck, the director of the Berlin Zoo, actually raided the animals from the Warsaw Zoo after the invasion of Poland.) However, World War II would ultimately destroy Lutz’s Berlin stock, bred mainly from fighting bulls, leaving only Heinz’s Munich blend, from which all Heck cattle descend. Behold! The modern aurochs! (Or is it?)
Forget, for a minute, your instinctual distrust of Nazi animals, and ask yourself the larger question: What makes a horse? Is an animal defined by what it is, or what it does? The answer might depend on whether you ask a geneticist or an ecologist. The Heck bull, it turns out, is decidedly not an aurochs, as DNA analysis of aurochs bones has determined that African and Indian cattle are more closely related to the ancient beast than European cattle are, the European stock having been domesticated far later. In other words, the European bull is a descendant of the aurochs, but so distantly that the genetic code has been scrambled too much to recover — the difference between piecing together a puzzle and piecing together a windowpane that’s been shattered by a cannonball. The Hecks should have built their bull from African cattle and Indian zebus, mixed in with Lutz’s Spanish fighting bulls. So the Heck bull isn’t an aurochs… but it has the size, the look, and the temperament of one. If let loose in the last wild forest of Europe, it might browse the same plants. Were there still wolves and lions there, it might be predated by those. It might have the same parasites, and fertilize the same pastures. So, couldn’t it, in effect, be so fine a replica of an aurochs that Nature itself might be fooled? Or is it only the naturally-crafted genetic code that matters? Or is the question moot? Is it impossible for a reconstituted aurochs to ever truly act and stand in for a genetically pure one?
These questions are important, as we head into an era of unprecedented man-made extinctions, and as the “re-wilding” campaign takes off. The Brothers Heck only had selective breeding with which to Frankenstein their animals; today, we’re not far from Jurassic Park-style genetic modification. Today, the Siberian tiger sits on the doorstep of utter oblivion; would it be wrong to hybridize it with, say, the Bengal? Would a partially Siberian tiger be better than no Siberian tiger at all? What about the American Bison? Reports of the buffalo population’s miraculous recovery rarely mention that there is only one herd left that is unmixed with cattle genes. Should we exterminate the hybrid buffalo to save the pure buffalo? Can we bring the mammoths and mastodons back to the Northern tundra? Already, a back-breeding project is attempting to recreate the Barbary Lion, the largest lion in human history. The last wild Barbary lion as killed in the 20th century, but genetically mixed Barbary lions exist in zoos; by selective breeding, we might be able stitch their DNA together like editing a film reel. Or perhaps not. Whatever your ethical or scientific qualms with genetic tampering, the conundrum of back-breeding will prove impossible to ignore in this century. Everything is fractured now. The question is whether we should try to make a mosaic.