e-DNA

Description

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Context

Researchers from two teams have independently shown that environmental DNA (e-DNA) can potentially identify and monitor terrestrial animals.

What is e DNA?

Environmental DNA or eDNA is DNA that is collected from a variety of environmental samples such as soil, seawater, snow or air, rather than directly sampled from an individual organism.
As various organisms interact with the environment, DNA is expelled and accumulates in their surroundings from various sources.
Example sources of eDNA include, feces, mucus, gametes, shed skin, carcasses and hair.
Thus, in a nutshell: Animals shed DNA through their breath, saliva, fur or faeces into the environment. These samples are called e-DNA.

Analysis

Such samples can be analyzed by high-throughput DNA sequencing methods, known as metagenomics, metabarcoding, and single-species detection, for rapid monitoring and measurement of biodiversity.

Recent Studies

Spotting animals can be challenging, especially if they inhabit inaccessible habitats.
The research shows that findings could help understand the composition of animal communities and detect the spread of non-native species.
This further indicates a big potential of airborne e-DNA to be used for conservation of terrestrial vertebrates.
The e-DNA technique can now provide accurate data for population census.

Significance

With eDNA, all pathogens can be monitored in an environment regardless of where they come from.
An integrated eDNA monitoring program could cost-effectively provide advanced warning of human, livestock and wildlife diseases.

eDNA metabarcoding

eDNA metabarcoding is a novel method of assessing biodiversity wherein samples are taken from the environment via water, sediment or air from which DNA is extracted, and then amplified using general or universal primers in polymerase chain reaction and sequenced using next-generation sequencing to generate thousands to millions of reads. From this data, species presence can be determined, and overall biodiversity assessed. It is an interdisciplinary method that brings together traditional field-based ecology with in-depth molecular methods and advanced computational tools.

https://www.downtoearth.org.in/news/wildlife-biodiversity/dna-from-air-may-help-identify-track-animals-in-the-wild-studies-81018

https://www.sciencedirect.com/science/article/pii/S2351989418303500#:~:text=Environmental%20DNA%20(eDNA)%20metabarcoding%20is,using%20next%2Dgeneration%20sequencing%20to