Environmental DNA

Environmental DNA (eDNA) is an innovative field in environmental science. It can be defined as any genetic material that can be collected directly from environmental materials such as soil, silt, water, and so on, without any clear biological source material.

Because DNA from higher species persists in the environment, it may be collected and examined, making it a significant tool for combating issues related to biodiversity monitoring.

This DNA can come from a variety of sources, including expelled cells or tissue such as urine, faeces, hair, and skin, as well as dead individuals releasing the genetic material.

Its preservation time ranges from weeks in warm water to hundreds of years in cold, dry permafrost.

Environmental DNA has been employed in many areas of research, including molecular biology, ecology, paleontology, and environmental studies.

Workflow of environmental DNA studies – identification of organisms

Aside from identifying organisms, one of the practical applications of eDNA is to provide insights into early detection of invasive species by monitoring water or soil samples, allowing them to respond to invasions before they become prevalent.

Another important application is monitoring endangered species without harming their habitats, assessing their presence and abundance without direct touch. Changes in environmental conditions, such as pollution or climate change, can also have an impact on the composition of ecosystems, which can be represented by eDNA, allowing scientists to better understand the health and resilience of ecosystems.

Environmental DNA is also used in ancient DNA research; scientists have successfully extracted DNA samples dating back hundreds of years, allowing them to virtually recreate former ecosystems and the animals that lived in them. It has also been used in forensics, particularly in wildlife-related crimes.

As expected, technical advances have made eDNA analysis more affordable and accessible, employing high-throughput sequencing.

‘A 2-million-year-old ecosystem in Greenland uncovered by environmental DNA’

Paleoclimatic records from epochs 3.6 to 0.8 million years ago show that polar mean annual temperatures were 11–19ºC higher than they are today. Because fossils are uncommon, nothing is known about the biological populations that inhabited the Arctic during this period. An ancient eDNA record that dates to about 2 million years ago describes the diverse plant and animal assemblages of the Kap København Formation in North Greenland.

Team Let's Biologue!

References

Brown, E. A. (2022, August 5). Hidden DNA is revealing secrets of animals’ lives. National Geographic. https://www.nationalgeographic.com/animals/article/environmental-dna-sheds-light-on-animal-lives-edna

Kjær, K. H., Winther Pedersen, M., De Sanctis, B., De Cahsan, B., Korneliussen, T. S., Michelsen, C. S., Sand, K. K., Jelavić, S., Ruter, A. H., Schmidt, A. M. A., Kjeldsen, K. K., Tesakov, A. S., Snowball, I., Gosse, J. C., Alsos, I. G., Wang, Y., Dockter, C., Rasmussen, M., Jørgensen, M. E., … Willerslev, E. (2022). A 2-million-year-old ecosystem in Greenland uncovered by environmental DNA. Nature, 612(7939), 283–291. https://doi.org/10.1038/s41586-022-05453-y

Sahu, A., Kumar, N., Pal Singh, C., & Singh, M. (2023). Environmental DNA (eDNA): Powerful technique for biodiversity conservation. Journal for Nature Conservation, 71(126325), 126325. https://doi.org/10.1016/j.jnc.2022.126325

Thomsen, P. F., & Willerslev, E. (2015). Environmental DNA – An emerging tool in conservation for monitoring past and present biodiversity. Biological Conservation, 183, 4–18. https://doi.org/10.1016/j.biocon.2014.11.019