DNA Barcode
Definition
A short, standardised sequence from a defined locus used to identify a specimen to species by comparison against a curated reference library. Analogous to a retail barcode but based on nucleotide sequence rather than printed lines.
- Purpose
- Species-level identification from a short sequence
- Compared against
- Curated reference sequence library
- Analogy
- Retail barcode, but nucleotide sequence based
- Common use
- Wildlife and species identification casework
Common questions
How does DNA barcoding differ from full STR profiling?+
Barcoding identifies which species a sample came from using a standardised locus compared to a species reference library, while STR profiling identifies which individual within a species a sample came from using multiple variable loci.
What limits the reliability of a DNA barcode identification?+
The result is only as good as the reference library; a species absent from or poorly represented in the database can be misidentified as its closest relative that is present, so barcode results are reported against the specific library used.
Related terms
- BOLD Systems
- Barcode of Life Data System (University of Guelph, Canada). Holds over 9 million COI reference barcodes linked to voucher specimens, with mandatory...
- COI (Cytochrome C Oxidase Subunit I)
- The 648 bp mitochondrial gene region proposed by Paul Hebert in 2003 as the universal barcode locus. Its combination of interspecific variation...
- ElePhant Database
- A curated STR reference database for African savanna and forest elephants and Asian elephants, used to assign ivory to individual animals or...
- Minibarcode
- A 100-200 bp sub-region of the COI locus amplified when DNA is too degraded for the full 648 bp amplicon. Shorter target...
- STR (Short Tandem Repeat)
- A genomic locus where a 2, 7 base-pair unit is repeated in tandem a variable number of times between individuals. The variation...