Return of the Neanderthals

For now, the Neanderthal genome is an abstract string of billions of DNA letters stored in computer databases. But it naturally sparks the imagination: Could scientists use that genetic blueprint to create neo-Neanderthals in the flesh?

In the not-so-distant future, advances in genetic engineering might enable that feat, experts say. But whether such a resurrection should happen is another story.

Since the 1996 birth of Dolly the sheep, the world’s first cloned mammal, scientists have greatly expanded and improved on cloning techniques. They have cloned dogs, cats, rats, pigs, and cows, among other species. In 2003, researchers in Spain were the first to bring back an extinct species—the Pyrenean ibex, a wild mountain goat also called a bucardo—though the clone only lived for a few minutes.

All of these examples relied on a technique called nuclear transfer. Starting with an intact cell (fresh or frozen) of the animal they’d like to clone, scientists first remove the nucleus, where DNA resides, and insert it into a hollowed-out egg cell of the same or a related species. This hybrid egg is then implanted into the uterus of a female surrogate for gestation, and voilà: The surrogate gives birth to a clone.

But there are no intact Neanderthal cells-far from it. Decoding the Neanderthal genome meant piecing together many DNA fragments painstakingly extracted from 40,000-year-old bones. So how could cloning be possible?