From Tuesday’s paper: Twenty thousand years separate us from our prehistoric relations – let’s keep it that way
Our late cousins, the Neanderthals, continue to fascinate us, 20 millennia after the last ones died out. It is unsettling to think that another species of human, another sapient being, like us and yet not us, shared our world for 100,000 years. And there is something terribly poignant about the idea of their end, of the last members of a human species growing old and dying, unreplaced, a sort of foreshadowing of humanity’s own fate. That we may have driven them extinct makes it all the sadder.
All that may explain why, every so often, a story about the possibility of raising them from the dead pops up. Can we clone a Neanderthal? Can we make our dead relatives walk again? Should we?
George Church, a Harvard professor of synthetic biology, thinks so. In an interview with Der Spiegel, he said that the rate of technological progress will make it possible within decades. More importantly, he says, it will be beneficial, making the human genus more diverse, and so reducing the odds that we’ll drive ourselves extinct. But he is, I think, wrong: it is both technically unlikely, and an ethical landmine.
The obstacles are challenging enough. Prof Church’s optimism about cloning is not universally shared by his colleagues. For a start, as Alex Knapp says in an interesting piece in Forbes magazine, even ordinary human cloning is beyond us at the moment. We have successfully cloned various animals, most famously Dolly the Sheep, but also cattle, goats, dogs, horses and others. But behind each successful clone is a small pile of unsuccessful ones: Dolly was one of 29 cloned embryos. Many clones that do survive to term are plagued by health problems, stemming from copying errors in their DNA, and die young and in pain. Understandably, doing something similar with humans would be ethically unacceptable. The cloning process will have to become a lot more reliable before it could be used even on modern humans, to avoid dozens of stillborn or profoundly disabled children, and a similar number of traumatised mothers.
But Neanderthals aren’t modern humans, and we don’t have access to their uncorrupted DNA at the jab of a needle. Our only successful attempt to clone an extinct animal, the Pyrenean ibex, stretched the word “successful” to breaking point: the clone survived just seven minutes in 2009. And the ibex had become extinct only nine years earlier. Neanderthals have been extinct for at least 20,000 years and probably more; DNA corrupts on a timescale of centuries. It may be possible to piece together uncorrupted parts from various sources, as Church suggests, but it will be a mammoth (so to speak) task. As Knapp says, even once that’s done, there are other, fiddlier challenges: for example, mitochondria, the so-called power stations of our cells, have their own DNA. Would Homo sapiens’ mitochondria be sufficiently similar to work in Homo neanderthalensis cells? And would the complex ecosystem of bacteria in our intestines work in Neanderthal guts?
History shows us, though, that obstacles can be overcome, and genetic science is one of the fastest moving areas of human knowledge – DNA sequencing is now a million times faster than it was eight years ago, as Prof Church says. He may be right that a Neanderthal clone will be feasible in a few years. But even if it is, making a member of another human species could throw our entire ethical system into chaos.
We are lucky, as Homo sapiens, that we have no surviving relatives closer than the chimpanzee: our common ancestor died 6.4 million years ago. Our moral and legal systems are based on the idea that humans are distinct from animals, and morally more important. Killing a human is murder: killing a chimpanzee is animal cruelty. But, as Richard Dawkins has said, if we were to find a population of, say, Australopithecus, an early human ancestor, in a jungle somewhere, that distinction would be destroyed. Do we class them as human, or animal? If animal, what if we then find a Homo erectus or Homo habilis? Do we draw up some apartheid system, based on tool-using abilities, language, cranial capacity? A reborn Neanderthal would present the same problem. Besides, the Neanderthal itself would be born into an alien world: even if it turned out to be psychologically indistinguishable from us (unlikely), it would be an anatomical freak, and its life would be a freak show.
This isn’t an argument against “playing God”. We already play God, with medicine and agriculture and everything. We should do it more: as Prof Church says, science is not far from putting amazing bio-machines on the market, microorganisms that can clean pollution and fight disease and make fuel for cars. No doubt making fire was called “playing God”. One generation’s playing God is the next’s heart-and-lung transplant. When we do it, though, we need to do it for a reason, and the only – utterly inadequate – reason for cloning a Neanderthal would be to say that we could.