The thylacine, or Tasmanian tiger, was the top dog of the marsupial food chain until Asian dingoes, introduced 4,000 years ago, forced the animal off Australia and onto Tasmania. European hunters finished off the job, exterminating the animals they blamed for livestock kills. The last thylacine died at the island's Hobart Zoo in 1936. The next one may be born as soon as 2010, cloned from animals that have been dead for a century.
Scientists at the Australian Museum in Sydney started a thylacine cloning project in 1999; now work by molecular biologist Karen Firestone of the nearby Taronga Zoo in Mosman may bring it to fruition. Museum researchers have extracted DNA from the bone marrow and internal organs of museum specimens, including a thylacine pup preserved in a pickle jar. They cannot yet reconstitute the entire genome, however, and the snippets they have recovered are badly degraded. So Firestone is using DNA-repair enzymes to fix the damaged bits in an attempt to clone and replicate the fragments before linking them into longer pieces, which she copies using a common DNA-replication technique. If it works, the scientists will craft artificial thylacine chromosomes, transfer them into egg cells from a related species such as the Tasmanian devil, and implant the eggs into a female host. "The idea is to eventually have a self-sustaining population of thylacines reintroduced to the wild," Firestone says. "I'm not sure we will ever have the resources to make it happen, but this iconic species was the last representative of an entire family of animals. Humans exterminated it. We have an obligation to put it back."
