In a petri dish in the bowels of Harvard Medical School scientists have tweaked three genes from the cells of an Asian elephant that help control the production of hemoglobin, the protein in blood that carries oxygen. Their goal is to make these genes more like those of an animal that last walked the planet thousands of years ago: the woolly mammoth.
"Asian elephants are closer to mammoths than either is to African elephants, yet quite different in appearance and temperature range," notes Harvard geneticist and technology developer George Church. "We are not trying to make an exact copy of a mammoth, but rather a cold-resistant elephant."
But what if the new—and fast advancing—techniques of genome editing allowed scientists to engineer not only cold-resistance traits but also other characteristics of the woolly mammoth into its living Asiatic relatives? Scientists have found mammoth cells preserved in permafrost. If they were to recover cells with intact DNA, they could theoretically “edit” an Asian elephant’s genome to match the woolly mammoth’s. A single cell contains the complete genetic instruction set for its species, and by replicating that via editing a new individual can, theoretically, be created. But would such a hybrid—scion of an Asian elephant mother and genetic tinkerers—count as a true woolly mammoth?
In other words, is de-extinction a real possibility?
The answer is yes. On January 6, 2000, a falling tree killed the last bucardo, a wild Iberian ibex, which is a goatlike animal. Her name was Celia. On July 30, 2003, Celia's clone was born. To make the clone scientists removed the nucleus of a cell from Celia intact and inserted it into the unfertilized egg cell of another kind of ibex. They then transferred the resulting embryo to the womb of a living goat. Nearly a year later they delivered the clone by cutting her from her mother.
For the rest of the story: http://www.scientificamerican.com/article/fact-or-fiction-mammoths-can-be-brought-back-from-extinction/