Molecular identification with context and references.
DNA barcoding compares DNA regions from a biological sample with reference sequences. The result depends on the material, marker and available information about the group under investigation.
From sample to a tentative identification.
Analyzing a marker region allows a sequence to be compared with references associated with identified organisms. This comparison can support the taxonomic identification of a biological sample.
Interpretation considers sequence quality and the consistency of the references. A molecular match should be evaluated alongside the available information about the material and its context.
Barcoding and metabarcoding address different situations.
DNA barcoding focuses on the molecular identification of an individual sample. Metabarcoding focuses on investigating different organisms in a mixture.
The decision does not depend solely on the name of the technique: it depends on the composition of the material and the objective. A protocol designed for an individual sample should not be assumed to be suitable for a mixture.
Explore the approach for mixtures ↗Four points to define the scope.
- Sample: provenance, preservation, storage and the possibility of obtaining usable DNA.
- Marker: suitability for the group and ability to distinguish the organisms of interest.
- References: taxonomic coverage, identification and quality of the available sequences.
- Resolution: assess whether the data support identification at the species, genus or another taxonomic level.
Complementary evidence for identification.
Barcoding can support the investigation of samples whose identification requires molecular evidence, comparisons with previous identifications and taxonomic studies. Its usefulness depends on the question and sample quality.
Morphological information, sample provenance and supporting records help interpret the result. When available, they should inform the discussion of the scope.
Explore study contexts ↗Not every sequence supports species-level identification.
Missing or inconsistent references and markers with limited discriminatory power can restrict identification. An inconclusive result should not be converted into a more precise identification than the data allow.
Analysis of a single marker alone does not establish the discovery of a species or necessarily resolve complex taxonomic questions. Additional evidence may be needed.
Shall we assess the material and the identification needed?
Tell us about the project context, environment and the question you need to answer. An initial conversation helps define the approach and scope.