The last known Pyrenean ibex, a wild goat named Celia, died more than two decades ago, the victim of a falling branch. But before she died, scientists managed to biopsy her skin and stash the sample in a freezer. They were already envisioning a future in which cloning might enable geneticists to bring species back to life.
In 2003, they thawed those cells and made a first attempt to clone Celia. Since they didn’t have any living Pyrenean ibex, they had to get creative. They removed genetic material from goat eggs and replaced it with DNA from Celia’s skin cells. After a mild electric shock, the eggs began to divide. The scientists then implanted these embryos into surrogate moms — goats or goat hybrids. This process — known as interspecies cloning — is tricky. One kid made it to term, but he died a few minutes after he was born.
Francisco Pelegrí first learned about the ibex cloning effort when one of his students brought a news article describing the feat to class. Pelegrí, a geneticist, was stunned. “From a technical perspective, it didn’t make sense,” he says. “By the time you only have 100 individuals, you’re pretty close to extinction.” The researchers had cells from a single animal, and they were trying to bring an entire species back. “It struck me that we really are not prepared for this at all,” Pelegrí says.
The Earth is in the midst of a sixth mass extinction event, and most scientists point to human activity as the primary cause. Each day, the planet loses an average of five to 30 species. While efforts are under way to preserve their habitat, these efforts may not be enough to save them. Extinct species, by definition, no longer exist. But their genetic material can live on in biobanks, offering the possibility of resurrection. Think of it as an extinction loophole.