Mining
Biodiversity analyses for environmental studies, monitoring and conservation actions.
Environmental DNA
Traces of DNA. Questions about biodiversity.
Environmental DNA connects environmental samples with the investigation of organisms. MetaGen helps define the molecular approach and interpret results in the context of the study.
01 / CONCEPT
The environment holds traces.
Organisms release genetic material into the environment. Analyzing this DNA allows evidence of their occurrence to be investigated without relying on directly observing or capturing each organism.
Environmental DNA is the material being investigated. Metabarcoding is one analytical approach: it uses DNA regions to study mixtures of organisms. The two terms are related, but they are not synonymous.
Understand the analytical process ↗02 / SAMPLING
The sample type follows the question.
Water, soil and sediments can contain environmental DNA. The feasibility of each combination of sample type, protocol and group of interest must be assessed before sampling.
- Water
- Volume, sampling locations, filtration and preservation are sampling design decisions.
- Soil
- Environmental heterogeneity must be considered when determining the distribution and composition of samples.
- Sediments
- DNA retention and persistence require care when relating a detection to the time and location of occurrence.
03 / OBJECTIVES
What can the study investigate?
- Evidence of groups of organisms detectable in the sampled area.
- Differences in detected composition between locations or sampling campaigns with comparable designs.
- Information that complements existing biodiversity surveys.
- Monitoring and conservation questions compatible with the resolution of the analysis.
This list describes possible studies. It does not guarantee detection or represent results from MetaGen projects.
04 / FROM FIELDWORK TO INTERPRETATION
An integrated process.
Study design
Define the objective, scale, sample types, groups of interest and sampling strategy.
Sampling and preservation
Plan procedures, records and controls to reduce the risk of contamination and DNA loss.
Molecular analysis
Assess markers and procedures appropriate to the material and the question.
Bioinformatics and interpretation
Process sequences and interpret taxonomic assignments in light of their limitations and the sampling context.
05 / CONTEXTS
Different contexts. A specific design.
Environmental consulting firms
Molecular tools integrated into the planning and delivery of your studies.
Energy and infrastructure
Information for environmental studies and programs at different project stages.
Conservation
Genetics applied to conservation, restoration and biodiversity monitoring.
Research
From the scientific question to molecular analysis and bioinformatic processing of results.
Use in each context depends on how well the method fits the question and project requirements.
06 / RESPONSIBLE INTERPRETATION
Evidence has limits.
- Detection does not pinpoint location
- DNA can be transported and persist in the environment. A detection alone does not prove that the organism was alive at that location and time.
- Non-detection does not prove absence
- Sampling, degradation, inhibition and analytical sensitivity influence detection.
- Sequences are not counts of individuals
- Amplification biases and differences in DNA release prevent a direct conversion between reads and abundance.
- Identification depends on references
- Markers and reference databases determine taxonomic resolution. Some assignments may remain above species level.
eDNA should be interpreted alongside the sampling design and other evidence from the study.
07 / METAGEN’S ROLE
We start with your question.
A technical discussion connects the study objective with the possibilities of molecular analysis.
We align the context, organisms of interest, planned sampling and interpretation needs. The proposal defines the steps, responsibilities and deliverables; the method is not selected before this discussion.
- Which decision or question guides the study?
- Are previous samples or data available?
- Which locations, sample types and sampling campaigns are planned?
- What level of information is needed?
08 / FREQUENTLY ASKED QUESTIONS
Before you begin.
Does eDNA replace conventional surveys?
Not as a general rule. Molecular methods and conventional surveys provide different information and can complement one another. The choice depends on the question, environment and study requirements.
Does non-detection prove that an organism is absent?
No. DNA may not have been collected, preserved or detected under the study conditions. Interpretation must consider sampling effort and the sensitivity of the approach.
Can individuals be counted from sequences?
The number of sequences is not a direct count of individuals. Inferences about abundance require specific design, calibration and validation; they are not an automatic outcome of metabarcoding.
Can I send samples that have already been collected?
Before sending samples, discuss the sample type, collection, preservation and storage history with MetaGen. These factors guide the feasibility assessment; sample suitability cannot be guaranteed without this review.
Which organisms can be identified?
The scope depends on the sample, markers and available references. Not every sequence can be identified to species level. The groups of interest and expected taxonomic resolution should be discussed when defining the scope.
TALK TO METAGEN
Shall we plan the next step?
Tell us about the project context, environment and the question you need to answer. An initial conversation helps define the approach and scope.