In the invisible realms of our natural world lies a groundbreaking frontier that has captivated scientists and researchers alike—Environmental DNA, or eDNA. Imagine being able to decipher the intricate tales of aquatic ecosystems or unveil the elusive presence of endangered species, all through the traces of DNA lingering in the air, soil, or water. The world of eDNA represents a scientific marvel, opening doors to a realm where genetic clues become powerful storytellers of environmental health, biodiversity, and ecological dynamics.
How does it work?
A scientist collects water samples using tools like the Niskin bottle attached to a CTD rosette or remotely operated vehicle. Each sample is labeled with latitude, longitude, depth, filter material, and the salinity and temperature of the collection site. The environmental DNA (eDNA) is extracted using a cellulose nitrate membrane filter and undergoes purification. The isolated eDNA is then preserved by freezing or immersion in a buffer solution. This aqueous solution prevents degradation and makes the DNA soluble, allowing storage for several years. This preservation method proves valuable when scientists encounter unknown species, enabling them to revisit and analyze the eDNA samples in the future.
What next?
After collection, eDNA samples are sent to a lab for DNA sequencing. DNA strands have four bases – adenine, guanine, cytosine, and thymine, known by their first letter for short – and every organism has a different pattern of A, G, C, or T. Scientists barcode, or label, each base sequence in a process called metabarcoding. These samples are then compared to others in a DNA database and the organism can be identified down to its family, genus, or species.
In the grand tapestry of scientific discovery, environmental DNA has emerged as a pivotal thread, weaving together stories of ecological resilience, biodiversity conservation, and a deeper understanding of our planet's intricate web of life. As researchers delve deeper into this genetic treasure trove, the world of eDNA promises to reveal even more secrets, guiding our efforts to protect and sustain the natural wonders that surround us.
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