Yellow-bellied water skinks (Eulamprus heatwolei) ethanol_collection_
Credit: CSIRO.
How 100-Year-Old Specimens Are Saving Australian Species
By Sarah Hard
Inside the sterile, climate-controlled vaults of the CSIRO’s new “Diversity” building in Canberra, millions of preserved specimens hold more than just DNA. They hold memories. For over a century, the shelves of Australia’s national collections have been filled with “spirit-preserved” reptiles, insects, mammals, fish and plants.
Until recently, these collections were viewed largely as static records of biodiversity – a catalogue of “what” used to live “where.” However, new research being conducted by a team at CSIRO, including Research Scientist Dr Erin Hahn of the Australian National Wildlife Collection, is proving that these jars are actually dynamic biological diaries. Through the application of archival chromatin sequencing, researchers are revealing that these specimens can teach us exactly how species responded to the environmental shifts of the past – and how they might survive the future.
The Power of Epigenetics
To understand why this research is a frontier science, one must look past the standard DNA sequence. While DNA has long been the gold standard for understanding evolution, it doesn’t tell the whole story of an individual animal’s life. Dr Hahn explains the difference using a powerful analogy.
“A DNA sequence is like the instruction manual of an organism, and it usually changes only slowly over many generations to adapt to changing environmental conditions. Epigenetic marks such as DNA methylation are chemical tags that sit on top of that sequence and can change much more rapidly in response to things such as temperature change, stress, or nutrition.”
Because these chemical tags persist long after an organism has been preserved in ethanol or “spirit” collections, researchers can now recover a molecular “snapshot” of how genes were being regulated while the animal was alive. Essentially, while the DNA tells us what the animal was, the epigenetics tell us what the animal experienced.
Recording the Stress of a Century
As Australia navigates the Anthropocene – an era defined by human-driven climate change – the ability to look back 100 years is invaluable. We are currently witnessing unprecedented bushfires, prolonged droughts, and shifting temperature gradients. By accessing the “environmental history” of specimens collected in the early 20th century, CSIRO researchers can see how wildlife navigated similar, albeit less frequent, stressors in the past.
According to Dr Hahn, the most consistently detected stressors in these molecular records include temperature extremes, climatic shifts, physiological stress, disease, and pollutant exposure.
“Because epigenetic marks regulate gene activity, they often capture the biological response to stress rather than the stressor itself,” Dr Hahn notes. This is a critical distinction for conservationists. It allows researchers to identify historical signatures of environmental pressures, such as habitat disturbance or pollution, by looking at how the animal’s biology fought back.
A New Baseline for Conservation
The most remarkable aspect of this research is the survival of the data itself. One might assume that a century in a jar of ethanol would degrade such delicate chemical signals, but the opposite is true.
“One of the most striking findings is that genome-wide chromatin and epigenetic patterns can remain detectable in specimens more than a century old,” says Dr Hahn. “These comparisons show that environmental responses leave measurable regulatory signatures that persist through time, opening the possibility of tracking how species have physiologically responded to rapid environmental change over the last century.”
This historical baseline is a gamechanger for protecting Australia’s endangered wildlife. Current conservation strategies often struggle because we lack data on what a “healthy” or “resilient” population looked like before modern industrialization. By using museum specimens, scientists can find the “gold standard” for a species’ biological health.
Dr Hahn says “this data helps conservation programs identify populations that were once more resilient, detect emerging stress responses earlier, and evaluate whether management interventions are improving population health.”
A preserved Thorny Devil (Moloch horridus). Researchers can now compare century-old specimens to modern descendants to track physiological changes.
Credit: CSIRO.
The Diversity Revolution
This research is part of a broader shift in how Australia manages its scientific heritage. The CSIRO’s Diversity building represents a physical manifestation of this shift. By co-locating massive historical collections – like the Australian National Insect Collection – alongside state-of-the-art molecular labs, the barrier between the past and the future has been removed.
Dr Hahn notes that this co-location has “revolutionised how we access molecular data from historical specimens.” No longer are these specimens tucked away in dusty basements; they are in the hands of genomicists using cutting-edge sequencing technology.
The CSIRO’s new ‘Diversity’ building in Canberra, where historical archives meet modern molecular science.
Credit: CSIRO.
The Next Frontier
As sequencing technology becomes more affordable and sensitive, the scale of this research is set to expand from individual case studies to landscape-wide analyses. CSIRO is looking toward a future where millions of archived specimens become accessible for genome-wide and epigenomic analyses.
“The next frontier is moving from sequencing historical DNA alone to reconstructing historical gene activity and environmental responses at large scales across collections,” Dr Hahn says. As methods improve, this massive library of Australian life will allow researchers to track how species have adapted – or failed to adapt – across the entire continent.
In the fight against extinction, the answers may not only lie in new technology, but in the silent, spirit-preserved memories of the specimens we have been keeping safe for a hundred years.
Author Bio:
Sarah Hard is a conservation writer based in Australia. She focuses on telling the unique stories of Australian wildlife and aims to inspire environmental awareness through her articles.
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