May 26 2008

Resurrecting the Tasmanian Tiger

This is a cool story from the BBC. Australian scientists have been able to extract a cartilage gene from DNA taken from a preserved specimen of Tasmanian tiger 100 years old. They then placed that gene in a mouse, and the gene worked pretty much as the native mouse gene would.

Any resurrection of DNA from an extinct species provokes images of Jurassic Park. However, this is a long way from once again having Tasmanian tigers in zoos, or the wild. The Tasmanian tiger, or Thylacine, went extinct due to hunting, with the last specimen dying in 1933. Interestingly, there continues to be local legends that the animals still exist in the wild. It is sort-of their Bigfoot – the evidence consists of sounds heard in the wild, trace evidence, and tall tales.  But, alas, the evidence strongly suggests that the Thylacine is no more.

However, several museums have Thylacine tissue preserved in alcohol. This allowed the researchers to collect viable DNA. As these genetic techniques are developed further it is theoretically possible to resurrect an entire Thylacine through cloning. It remains to be seen of the DNA is complete and viable enough, but this study is encouraging.

Going forward, this technology also means that we can preserve endangered species, perhaps by freezing tissue, for later cloning. We have already done this for plants, creating several massive seed banks. Perhaps we can create a biodiversity preservation bank for endangered animals as well.

What about species that went extinct further in the past? The prospects get quickly more dim as we go back in time. We can extract Neanderthal and Mammoth DNA from specimens. Perhaps it might be possible to clone animals from thousands of years ago – but this will be much more difficult. It remains to be seen if this is possible, but we may find out in our lifetimes.

But, unfortunately, going back millions of years is almost certainly not possible. DNA simply does not survive for that long. We will not be seeing T-Rexes in Jurassic Park type zoos in the foreseeable future. This may never be possible, and if it is it will require techniques not yet theorized.

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