How to study eDNA

Environmental DNA, or eDNA, is DNA released into the environment by organisms through faeces, shed hair, discarded dead skin tissues, and carcasses.

Water, soil, snow, and air contain samples of eDNA.

While terrestrial eDNA remains in the surroundings for a longer time, aquatic eDNA stays for only about three weeks as water processes and ocean currents dilute and distribute them.

Essentially, wherever animals deposit their excreta or shed their hair or skin, scientists can pick up an eDNA sample from such spots.

It is possible to study eDNA through analysis followed by sequencing, where the building blocks of the DNA reveal unique information about the species.

Two approaches are typically adopted to amplify the eDNA sample:

The single-species method employs specific markers to identify a species.

This method enables researchers to determine whether a species is endemic or an invasive organism based on a comparative analysis of the eDNA from other native species.

The multiple-species technique uses generalised parameters for studying the eDNA sample.

This method allows taxonomists to understand species diversity within a population and even between populations living in the same area.