Playing God: should we revive extinct species?

Scientists have sequenced the DNA of the Tasmanian tiger, which died out in the 1930s, bringing them closer to recreating the animal - and there are plans to do the same with the woolly mammoth. But is it ethical to do so?

It sounds like something from a sci-fi B-Movie: scientists have moved a step closer to bringing the Tasmanian tiger back from extinction.

Also known as the thylacine, or Tasmanian wolf, the world's largest carnivorous marsupial died out in its native land sometime during the 1930s. Despite almost 4,000 reports of "sightings" since, including tantalisingly inconclusive video footage as recently as 2008, most regard the species as having gone for ever.