Amy-Jane Beer explains what eDNS is and how it helps determine evidence of different organisms

By Dr Amy-Jane Beer

Published: Monday, 27 February 2023 at 12:00 am

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DNA, or deoxyribonucleic acid, is the molecule found in the nuclei of living cells that carries the genetic instructions for making the entire organism – the genome.

Technology for interpreting and reading this code (known as DNA fingerprinting) is now so advanced that species can be identified from miniscule quantities of DNA. No longer is it necessary to have intact tissue samples or even whole cells to work with. 

• Phenotype guide: what it is, it’s relation to the genotype and the effect on evolution
• Does the tree of life reflect evolution?
• Endosymbiosis guide: what it is and why complex life needs endosymbiosis
• What are chromosomes and why are chromosomes important?

What is eDNA?

So-called environmental DNA (eDNA) can be extracted from water, soil, or other media, then amplified and decoded to provide evidence for the presence of a particular species without the organism ever being seen.

In the UK, the technique is particularly useful for confirming the presence of great crested newts (which are protected by law) in bodies of water, saving ecological consultants many long nights of surveying work.

Main image © Krista M. Ruppert, Richard J. Kline and Md Saydur Rahman, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

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