Scientists in Sweden have made a remarkable discovery by recovering RNA from the extinct Tasmanian tiger, or thylacine. This animal vanished from the wild due to excessive hunting and habitat loss. The last known thylacine died in 1936 at a zoo in Tasmania. It’s an incredible feat to trace the active genes in tissues from such an extinct species.
The study, led by Dr. Marc R. Friedländer at Stockholm University, focused on RNA because it shows which genes were active in living cells. While DNA reveals what genes exist, RNA provides insights into what genes were doing their jobs while the animal was alive. The dried skin at a Swedish museum allowed researchers to analyze muscle and skin samples, opening a window into the past of this unique marsupial.
RNA is fleeting; it breaks down faster than DNA, which makes studying ancient samples tricky. However, some preservation methods, like keeping specimens in dry storage, can help protect these fragile molecules. A 2019 study showed that RNA can survive in extreme conditions, such as permafrost. This study confirms that even samples stored in museums can retain useful genetic information.
To ensure the authenticity of the recovered RNA, researchers used advanced techniques. They found that most RNA sequences matched known thylacine genes, while some human sequences were present at a lower level, likely from handling over the years. They also employed metatranscriptomics, a method that identifies species and microbes to filter out contaminants.
In muscle tissues, the strongest signals indicated genes related to contraction and energy usage, revealing how the thylacine may have functioned while alive. The RNA pointed to specific muscle fibers and oxygen storage mechanisms, giving a glimpse into the animal’s physiology.
The skin samples revealed fragments from keratin genes, which correspond to the tough outer layer of animals. Interestingly, hemoglobin RNA was also found, indicating blood presence at the time of specimen preparation. The researchers observed clear distinctions between muscle and skin RNA, solidifying the accuracy of their data.
MicroRNAs, small molecules that regulate gene expression, were also recovered. These tiny regulators can be specific even among closely related species, providing further evidence of the functional differences between the thylacine and its living relatives.
The research helped improve the thylacine genome map, which is crucial for comparing extinct species to those alive today. By identifying gaps in earlier DNA studies, scientists can create a better reference for future genetic comparisons.
Additionally, the study detected traces of RNA viruses within the thylacine samples. While these signals were faint, they suggest that museum specimens can hold valuable information about viral history, shedding light on how viruses have evolved over time.
This groundbreaking research opens up new avenues in paleontology by pushing the boundaries of ancient RNA studies. It can reveal insights into cell types, injuries, and even diseases of extinct species. The findings underscore the need for careful preservation practices to ensure that future treatments of museum specimens do not result in lost data.
Scientists continue to search for more samples and data to broaden our understanding of extinct species. This research was published in Genome Research and stands as a testament to the scientific exploration of our planet’s past.
For more fascinating insights into this subject, you can explore resources like the National Museum of Australia and other scientific publications.
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