Scientists one step closer to recreating extinct species after breakthrough involving Tasmanian tiger

By REUTERS

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The last of its kind may have gone extinct in 1936, but a breakthrough could see the Tasmanian tiger walk the Earth again.

Researchers announced Tuesday they had recovered RNA - genetic material present in all living cells that has structural similarities to DNA - from the desiccated skin and muscle of a Tasmanian tiger stored since 1891 at a museum in Sweden. 

Scientists have recently extracted DNA from ancient animals and plants, some of which are 2 million years old, but this study marked the first time that RNA - much less stable than DNA - has been recovered from an extinct species. 

RNA sequencing, unlike DNA, provides experts with real biology and metabolism regulation that was happening in the cells and tissues of the Tasmanian tigers before they went extinct, which would be necessary to de-extinct the species.

Researchers announced Tuesday they had recovered RNA - genetic material present in all living cells that has structural similarities to DNA - from the desiccated skin and muscle of a Tasmanian tiger stored since 1891 at a museum in Sweden

While not the focus of this research, the ability to extract, sequence and analyze old RNA could boost efforts by other scientists toward recreating extinct species. 

The news comes as separate projects are in the works to bring back other extinct species, like the dodo bird that vanished more than 350 years ago. 

Colossal Biosciences, a startup based in Dallas, Texas, announced plans in 2022 to start the 'de-extinction' of the Tasmanian Tiger and woolly mammoth using stem cell technology.

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) - biomolecular cousins - are fundamental molecules in cell biology.

DNA is a double-stranded molecule that contains an organism's genetic code, carrying the genes that give rise to all living things. 

RNA is a single-stranded molecule that carries genetic information it receives from the DNA, putting this information into practice. 

RNA synthesizes the panoply of proteins that an organism requires to live and works to regulate cell metabolism.

'If we want to understand extinct species, we need to understand what gene complements they have and also what the genes were doing and which were active,' said geneticist and study co-author Marc Friedländer of Stockholm University and SciLifeLab.

The last known Tasmanian tiger, named Benjamin, succumbed in a Tasmanian zoo in 1936 (pictured)

The last known Tasmanian tiger, named Benjamin, succumbed in a Tasmanian zoo in 1936 (pictured)

There were questions about how long RNA could survive in the type of conditions - room temperature in a cupboard - that these remains had been stored. 

The remains, housed in the Swedish Natural History Museum, were semi-mummified, with skin, muscles and bones preserved but internal organs lost.

READ MORE: Scientists launch project to bring back the extinct species using stem cell technology

US startup Colossal Biosciences, based in Dallas, Texas, has just revealed plans to 'de-extinct' the dodo more than 350 years after being wiped out from Mauritius island in the 17th century. 

'Most researchers have thought that RNA would only survive for a very short time - like days or weeks - at room temperature,' said evolutionary geneticist Love Dalén of the Centre for Paleogenetics.

This is likely true when samples are wet or moist, but apparently not the case when they are dried.'

Aside from the tiger-like stripes on its back, the Tasmanian tiger resembled a wolf. The arrival of people in Australia roughly 50,000 years ago ushered in massive population losses. 

The 18th-century arrival of European colonizers spelled doom for the remaining populations concentrated on the island of Tasmania, with a bounty later put on them after they were declared a hazard to livestock. 

The last known Tasmanian tiger, named Benjamin, succumbed in a Tasmanian zoo in 1936.

'The story of the thylacine's demise is in a sense one of the most well-documented and proven human-driven extinction events,' said geneticist and bioinformatician Emilio Mármol Sánchez of the Centre for Palaeogenetics and SciLifeLab in Sweden, lead author of the study published in the journal Genome Research.

'Sadly, Tasmanian tigers were declared protected just two months before the last-known individual died in captivity, too late to save them from extinction.

'Although we remain skeptical about the possibility of actually recreating an extinct species using gene editing on living extant animal relatives - and the time-scale to get to a final point might be underestimated - we do advocate for more research on the biology of these extinct animals.'

Sweden

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