WOOLLY mammoths stomp through the Siberian tundra as the giant moa strides the forest floor of New Zealand and Tasmania's dog-like "tigers" stalk their prey under the cover of night. This is not a snapshot of times past, nor next year's sequel to Steven Spielberg's Jurassic Park.

Instead, it's a scenario that some biogeneticists see as plausible in our own lifetimes: the resurrection of species driven to extinction, sometimes thousands of years ago.

Today, some experts believe that by harnessing this breakthrough knowledge, the first extinct species could be revived within years.

They could be cloned from genetic material teased from preserved tissues, with the reprogrammed egg implanted in a cousin species. Farther down the road, other species could live again through artificially-reconstituted sequences of their DNA, goes the argument.

Scientists believe reconstruction would be feasible for most animals for which DNA has survived, possibly going back 200,000 years - a limit that would exclude a "Jurassic Park"-like revival of the dinosaurs.

London School of Economics sociologist Carrie Friese fears that ethics have been left by the wayside in the rush to resurrect. "My concern is that the focus is too much on: 'Can we do this?' rather than what we do with the living being that is the result," she said.