laboratory microscope

Environmental DNA (EDNA) is defined as genetic material that has been gathered from an environment rather than directly from an organism. DNA is a molecular structure that exists in an organism’s cells. EDNA is DNA that has been expelled from organism and left in behind in soils, water, sediments and in the air. All living organisms leave traces of their genetic material in environments that its physically been in; that DNA can give researchers information about a species’ whereabouts (past and present). EDNA can be released into an environment through the body fluids, fecal matter, scales and skin of the organism.

Environmental DNA Sampling

Ecological sampling is an assessment of how species are distributed and how dense the populations are within a community of organisms. Sampling requires the use of several methods to record the presence of different organisms. Some methods merely consist of photographing species, other methods involve setting traps to capture and identify them so that they can be studied up close.

Sampling with environmental deoxyribonucleic acid (EDNA) is a relatively new strategy for identifying the species in a given region. EDNA makes use of readily available genetic material deposited in a habitat and left behind by the organism that it came from. That genetic material can then be tested and referenced to other cataloged samples.

How Does DNA Degrade

Once EDNA has been released into an environment, it can become less detectable depending on the conditions of the region. For example, cold weather conditions sometimes preserve a DNA sample over long periods of time because freezing prevents samples from moving through the system. Alternatively, UV radiation or seawater acidity could cause the genetic sample to degrade. For this reason, DNA samples extracted from water tend to only last a few days. Therefore, like any other sampling technique, EDNA is time sensitive. Thanks to advances in molecular biology, retrieving information from genetic signatures and matching them to the appropriate species in labs is quickly becoming a new frontier for understanding species distributions across ecosystems.

Advantages of Environmental DNA

Acquiring a genetic signature from an organism (or a group of organisms) can can tell sampling teams a lot about the organism, including where it has been, what its diet consists of and what other organisms it may have interacted with. EDNA is more cost effective than trapping and capturing organisms because EDNA is readily available upon discovery, saving researchers the cost of traps and time for assembly and troubleshooting. Using EDNA also grants researchers a better opportunity to detect species that have low population densities.

What’s more, the EDNA technique is less disruptive to the lives of organisms in the region being sampled. When ecologists attempt to study species by capturing them or observing them directly, they often risk introducing non-native species or disease into an environment, even with the use of sterilized materials. In other cases, sampling teams could disrupt the targeted ecosystem in some unforeseen way. Of all sampling methodologies, EDNA is the least disruptive to ecological communities. Though measuring biodiversity is an essential process for conservation and research, preserving that biodiversity is likewise crucial.

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