Tasmanian tiger RNA is the first to be extracted from an extinct species

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For the first time, geneticists have been able to isolate and decode RNA molecules from a long-dead organism.

The genetic material – which came from a 130-year-old specimen of a Tasmanian tiger, or thylacine, in the collection of the Swedish Museum of Natural History in Stockholm – has allowed scientists to better understand how the animal’s genes work. The researchers shared their findings in a study published Tuesday in the scientific journal Genome research.

“RNA gives you the opportunity to go through the cell and tissue and find the real biology that was preserved in time for that animal, a thylacine species, right before it died,” said Emilio Marmol Sanchez, the study’s lead author and a computational biologist. At the Center for Paleogenetics and SciLifeLab in Sweden.

About the size of a coyote, the thylacine was a marsupial predator. They disappeared about 2,000 years ago almost everywhere except on the Australian island of Tasmania, where their populations were hunted to the point of extinction by European settlers. The last Tasmanian tiger to live in captivity, Benjamin, died from exposure in 1936 at Beaumaris Zoo in Hobart, Tasmania.

Marmol-Sanchez said that although de-extinction was not the goal of his team’s research, a better understanding of the Tasmanian tiger’s genetic makeup could help launch recent efforts to bring back the animal in some form.

Andrew Pask, of Leading a project aimed at reviving the Tasmanian tiger, He said the paper was “groundbreaking”.

“We previously thought that only DNA remained in the ancient museum and ancient specimens, but this paper shows that you can also get RNA from tissues,” said Pask, a professor at the University of Melbourne in Australia and head of the Tiger Tiger Integrated Genome Restoration Research Laboratory. “. .

“This will add great depth to our understanding of the biology of extinct animals and help us build much better genomes,” he added.

Ancient DNA, under the right conditions, can last for more than a million years, and has revolutionized scientists’ understanding of the past.

RNA, a temporary copy of a portion of DNA, is more fragile and degrades more quickly than DNA, and until very recently was not thought to last for any length of time.

In 2019, Team RNA sequenced from the skin of a 14,300-year-old wolf It was preserved in permafrost, but the latest research marks the first time RNA has been recovered from a now-extinct animal.

Marmol-Sanchez said this study is a proof of concept, and his colleagues now hope to recover RNA from animals that have long been extinct, such as the woolly mammoth.

The research team was able to sequence the RNA of skin, muscle and skeletal tissue from the sample and identify the genes of the Tasmanian tiger. This information forms part of what is known as the animal’s transcriptome, just as information stored in DNA is known as the genome.

DNA is often described as an instruction manual for life found in every cell of the body. In addition to other cellular functions, RNA produces proteins by making a copy of a specific stretch of DNA in a process known as transcription.

Understanding RNA allows scientists to build a more complete picture of the biology of the animal, Marmol Sanchez He said. He uses the analogy of a city where every restaurant is given a huge recipe book – its DNA. However, it is RNA that allows each restaurant to produce different dishes from this reference book.

“If you just focus on the DNA, you won’t be able to see the differences between all these restaurants,” Marmol-Sanchez said. “With RNA…you can now go to a restaurant and taste food, or taste paella, or sushi, or sandwiches.”

He added: “You can learn a lot… by reading those recipes, but you will miss the real parts of the metabolism and the biology that are in all those restaurants or the cells between them.”