Wrap: four organisms that could be brought back from the brink of extinction (and beyond)

How scientists are bringing vulnerable or vanished species back (or, so they say).

This undated handout photo received on May 20, 2008 from the University of Melbourne shows two Tasmanian Tigers before their extinction in the 1930s. Scientists said on May 20, 2008 they had "resurrected" a gene from the extinct Tasmanian tiger by implanting it in a mouse, raising the long-term possibility of bringing animals such as dinosaurs back to life. In what they describe as a world first, researchers from Australian and US universities extracted a gene from a preserved specimen of the doglike marsupial -- formally known as a thylacine -- and revived it in a mouse embryo. RESTRICTED TO EDITORIAL USE GETTY OUT AFP PHOTO/UNIVERSITY OF MELBOURNE (Photo credit should read AFP/AFP/Getty Images)