Tiger yields hairy genome sequence

US researchers have sequenced the mitochondrial genome of the thylacine, better known as the Tasmanian tiger.

Using the same techniques as they developed to sequence the genome of the woolly mammoth last year, the team extracted DNA from the hair of two preserved thylacines: one from a skin held by a museum in the US and the other from an ethanol-preserved whole specimen held by Stockholm University.

The team, led by Webb Miller and Stephen Schuster of Pennsylvania State University, reported their findings in the January 13 issue of Genome Research. They intend to publish a further analysis of the thylacine’s nuclear DNA in the future.

The study has also clarified the phylogenetic position of the thylacine – a marsupial more closely related to kangaroos than to the dogs they most resemble.

The researchers add weight to the view that the thylacine belongs to the Dasyuromorphia clade, which includes extant species such as the Tasmanian devil, the numbat and the quoll.

And like the devil, it seems that the thylacines may have suffered from an extremely low level of genetic diversity, which may have led to them dying out if they hadn’t been hunted to extinction.

The ability of the researchers to extract enough thylacine DNA from the hair samples, despite a great deal of contamination from human and bacterial DNA and their temperature storage history, has led the researchers to propose that other museum samples of extinct creatures may yield similar results.

The ability to extract DNA from the hair of the woolly mammoth was made easier by its frozen history.

The thylacine skin sample, on the other hand, has been kept at room temperature since the animal died in 1905.

A new discipline could now arise, says Schuster, which he has dubbed ‘museomics’.

“The collections dating back several hundred years and now housed in the world’s museums of natural history are the treasure troves of science,” he said.

He said the team hoped to add DNA sequence data to taxonomic data to more clearly define species, and with the technique of using hair rather than drilling into valuable old bones, museum curators would be happier to collaborate.

“The advantages of obtaining DNA from hair makes museomics possible on a wide scale,” he said.