Marsupials have a long history. It became the first extinct animal family from which scientists extracted ribonucleic acid (RNA), the molecule that brings life to the species’ genome. Using a specially modified protocol, a Swedish research group extracted millions of strands of ribonucleic acid (RNA) from the skin and muscles of a 132-year-old marsupial.
The carnivorous striped marsupial, known to scientists as the marsupial wolf, was hunted to extinction on the Australian island of Tasmania in the 1930s. RNA is the genetic material that converts information encoded in DNA into proteins. Their recovery from extinct animals, such as marsupials, could unlock a treasure trove of information about genetic activity that was thought to have been lost long ago.
Recovering RNA expression profiles that no longer exist in living cells expands the possibility of delving into the biology of extinct animals. – writes A Science Alert. Mark Friedlander, a molecular biologist at Stockholm University, said: This is the first time we have glimpsed the presence of thyroid-specific regulatory genes, such as microRNAs, which have been extinct for more than a century.
By reading DNA sequences, we can find out which genes a species possesses. RNA sequences reveal which genes are actually “switched on” and which proteins cells use to produce them. However, RNA is much more fragile and degrades much faster than DNA, so preservation of historical specimens is challenging. Marmol-Sanchez and his colleagues took six muscle and skin samples from a marsupial that was cataloged in 1891 and preserved at the Natural History Museum in Stockholm.
What can we learn from RNA?
RNA extracted from a 132-year-old marsupial is far from the oldest. In recent years, dogs have been frozen for approximately 14,300 years. In addition, RNA was obtained from a 5,300-year-old mummified human iceman. The ancient wolf has no clear taxonomic rank, but its family is still alive today, making the marsupial the first truly extinct animal whose RNA has been recovered.
Some RNA shows signs of damage, which is to be expected if it has been preserved for hundreds or thousands of years or if chemicals were used for mummification. The samples were contaminated with human and possibly bacterial RNA, but the researchers were able to confirm the authenticity of the marsupial RNA sequence by comparing it to the species’ genome.
RNA containing tissue-specific proteins has been found in muscle samples, while skin-specific patterns have been found in the skin. The research team is excited about their findings, which they hope will aid ongoing efforts to revive marsupials. This project raises several ethical and technological issues. But more than that, sequencing RNA from extinct species could give researchers the opportunity to detect the presence of different RNA viruses over time. This could accelerate our understanding of viral evolution.
Although these studies are interesting for scientists, there is another legitimate question. How did a marsupial from a remote Australian island end up in a Swedish museum half a world away from where it once lived?
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