Environmental DNA (eDNA) is defined as genetic material obtained directly from environmental samples such as soil, sediment, water, snow, air, etc. or leftovers from an organisms such as hair, feces or carcasses.  Sampling eDNA is an efficient, non-invasive and easy-to-standardize approach with great potential as a monitoring tool for wildlife in aquatic, marine or terrestrial ecosystems.  Unlike traditional monitoring of biodiversity, which relies on visual observation, eDNA overcomes some of the limitations such as spotting a rare or endangered species. When it comes to microorganisms, eDNA has already revolutionized the understanding of microbial ecology.  eDNA constitutes a great opportunity to study the role and ecology of organisms and get insight into their metabolism, function and evolutionary relationship.

Studying eDNA involves a series of methods based on DNA collected directly from the environment to identify the presence of organisms either by Q-PCR or by metabarcoding at the individual, population, species, genus or family level or for the determination of biodiversity and ecosystem characterization.

eDNA builds on skills in molecular biology, population genetics and bioinformatics coupled with ecology, biology and/or agronomy and is rapidly evolving field, and with the reducing DNA sequencing cost, it is becoming more and more popular tool used in almost all environments.  eDNA is a technological advanced tool which in addition to presence/absence of the species, also provides genetic information of the organism, which can be used to trace species relatedness, genetic diversity, activity and function.