The Dodo, Raphus cucullatus, is one of the most well-known extinct animals (Image: Photo Researchers / SPL)

THE recipe for making any creature is written in its DNA. So last November, when geneticists published the near-complete DNA sequence of the long-extinct woolly mammoth, there was much speculation about whether we could bring this behemoth back to life.

Creating a living, breathing creature from a genome sequence that exists only in a computer’s memory is not possible right now. But someone someday is sure to try it, predicts Stephan Schuster, a molecular biologist at Pennsylvania State University, University Park, and a driving force behind the mammoth genome project.

So besides the mammoth, what other extinct beasts might we coax back to life? Well, it is only going to be possible with creatures for which we can retrieve a complete genome sequence. Without one, there is no chance. And usually when a creature dies, the DNA in any flesh left untouched is soon destroyed as it is attacked by sunshine and bacteria.

There are, however, some circumstances in which DNA can be preserved. If your specimen froze to death in an icy wasteland such as Siberia, or snuffed it in a dark cave or a really dry region, for instance, then the probability of finding some intact stretches of DNA is much higher.

Even in ideal conditions, though, no genetic information is likely to survive more than a million years – so dinosaurs are out – and only much younger remains are likely to yield good-quality DNA. “It’s really only worth studying specimens that are less than 100,000 years old,” …