Would it be ethical to genetically resurrect Neanderthals?
We're still (at least) many years away from being able to clone a Neanderthal. But if we could, what would be the ethical ramifications of cloning our closest genetic relative?
Scientists have greatly expanded the field of genetic engineering, and have cloned many different animals since the first cloned mammal, Dolly the sheep, in 1996. And in addition to cows, pigs, rats, dogs and cats, researchers in Spain successfully cloned an extinct mountain goat, the Pyrenean ibex. The resulting goat died after only a few minutes, but it raises the question, could we clone Neanderthals?
Current cloning uses a process called nuclear transfer. In nuclear transfer, scientists remove the nucleus from a cell of the cloned animal and insert it into a hollowed-out egg cell from an animal of the same or related species. Then the combined egg is implanted into the uterus of a surrogate who will birth the unrelated animal.
Unfortunately, nuclear transfer is impossible for Neanderthals: we have no intact cells from which to extract the nucleus. However, a new method proposed by Harvard geneticist George Church might work for our prehistoric cousins. Church's method, called CRISPR, makes adjustments on the DNA of a cell from a related species. In the Neanderthals' case, a human stem cell could be used. The Neanderthal genome was sequenced in 2009, so Church's technique could potentially be feasible.
But if the CRISPR technique, which sounds more like a toaster-oven cooking method, is possible, would it be ethical to resurrect the Neanderthal? First, the genetically engineered Neanderthal egg cell would have to be carried by a human or chimpanzee surrogate, and impregnating a human woman with a Neanderthal certainly sets off a few alarm bells.
And would it be right to bring a Neanderthal child into our human society? Neanderthals were very complex, and their brains are believed to have been capable of language and abstract thinking. But it's unclear if Neanderthal brains were as developed as humans are, and a Neanderthal living in human society might be seen as a mentally handicapped human rather than a distinct species, and ostracized for its familiar yet different appearance.
Neanderthals disappeared before the Agricultural Revolution too, so it's unclear if a Neanderthal could even survive eating a human diet, since they predate cooking and farming.
"For any species, we want to maximize the chances that they will be born and live physically and socially healthy lives," Church told National Geographic News.
Regardless of ethics, we probably won't be seeing a Neanderthal child running around anytime soon. Cloning still hasn't been perfected, especially with extinct species. The Spanish scientists who cloned the Pyrenean ibex created 439 cloned eggs, but only 57 made it into embryos. Only five survived the full pregnancy, and only one survived birth. That many failed pregnancies would have a huge emotional and ethical toll on human surrogates.
"What's more likely to happen is you're going to get really sick or lethal mutations," said Yale geneticist James Noonan. "You're going to get a lot of dead proto-Neanderthals."
