DNA Barcoding
Definition
Species identification using a short, standardised region of the mitochondrial genome. For animals, the primary barcode marker is a 648-base-pair segment of cytochrome c oxidase I (COI). The unknown sequence is matched against reference databases such as BOLD or GenBank. Barcoding works on processed and degraded samples because mitochondrial DNA is present in high copy number per cell.
- Standard plant regions
- rbcL and matK
- Standard insect region
- COI (cytochrome oxidase I)
- Requires comparison against
- curated reference databases like BOLD or GenBank
Common questions
What is DNA barcoding and why is it used in forensics?+
DNA barcoding is a method that identifies a species by sequencing a short, standardized region of its genome and comparing it against a reference database. It's forensically useful because it works on degraded material, like seeds or leaves destroyed by cooking, chewing, or putrefaction, when morphology alone can't identify the specimen.
What gene regions are used for DNA barcoding in different organisms?+
For plants, rbcL and matK are the standard regions sequenced. For insects, COI (cytochrome oxidase I) is most common. For some species like pangolins, cytochrome b or COI are used. The choice depends on the organism's characteristics and availability of reference sequences.
Does DNA barcoding work on old or damaged material?+
Yes, it performs well on degraded material because the target regions are short and often amplifiable from fragments that morphology can no longer identify. However, it does require some extractable DNA, so very degraded or ancient material may pose challenges.
Related terms
- BOLD
- Barcode of Life Data System, an international curated database linking COI sequences to verified voucher specimens with collection locality and taxonomic annotation....
- Cytochrome B (Cytb)
- A protein-coding gene in the mitochondrial genome used widely for vertebrate species identification. Its moderate mutation rate resolves most closely related species...
- matK
- Maturase K gene, located in the chloroplast trnK intron. The second CBOL-approved plant barcode marker, with an approximately 870 bp diagnostic amplicon....
- rbcL
- A chloroplast gene encoding the large subunit of RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase). One of the two CBOL-standardized plant barcode loci. Widely amplifiable but...
- Agarwood
- Resin-impregnated heartwood produced by Aquilaria and Gyrinops species in response to fungal infection or wounding. Used in incense and perfume (oud oil)....
- Arylnaphthalide Lignan
- A plant secondary metabolite class to which the cleistanthins (Cleistanthus collinus toxins) belong. The cleistanthins damage the distal renal tubule, producing a...
- BOLD (Barcode of Life Data System)
- A curated online reference database of barcode sequences maintained by the University of Guelph, Canada. Each entry includes a voucher specimen, taxonomic...
- Cardiac Glycoside
- A steroidal compound that inhibits the sodium-potassium ATPase pump in cardiac myocytes, raising intracellular calcium and producing bradyarrhythmia, AV block and hyperkalaemia....
- Chain of Custody
- The documented chronological record of who collected, handled, transferred, and examined a piece of evidence. For digital evidence, chain of custody includes...
- Chloroplast Genome (Plastome)
- A circular, 120-160 kb genome inside plant chloroplasts, present in hundreds of copies per cell. Its high copy number makes it recoverable...
- CITES
- The Convention on International Trade in Endangered Species of Wild Fauna and Flora, a multilateral treaty signed in 1973 now with over...
- CITES Appendix
- CITES classifies listed species into three appendices. Appendix I prohibits commercial trade; Appendix II permits trade only with documented permits and quota...
Explained in these topics
- CITES Flora and Plant Product ForensicsSpecies identification using a short, standardized genomic region (for plants: rbcL + matK) that is amplifiable from degraded material and compared against a c...
- Modern Immunological and Molecular Approaches to Species IdentificationSpecies identification by sequencing a short, standardised mitochondrial gene region, most commonly cytochrome c oxidase subunit I (COI) for animals or 12S rRN...
- Molecular Identification of Forensically Important InsectsUsing a standardised short gene region (most commonly COI) to assign an unknown specimen to a species by comparison against a reference library of verified seq...
- Non-Human DNA and Species IdentificationThe sequencing of a short, standardised genetic region to assign a specimen to a species. For animals, the primary barcode markers are a 648-bp segment of COI...
- Pangolin Scale ForensicsSpecies identification by sequencing a short, standardized gene region (cytochrome b or COI) and comparing it against a reference database. Requires extractabl...
- Plant DNA Barcoding: rbcL and matKIdentification of an organism's species by sequencing a short, standardised region of its genome and matching the sequence against a curated reference database.
- Plant Poisons of Medico-Legal Importance in IndiaIdentification of an unknown plant fragment by sequencing short standard genome regions (rbcL and matK for plants, ITS for fungi). Routinely used at NFSU Gandh...
- Wildlife Crime and Biological EvidenceSpecies identification using a short, standardised region of the mitochondrial genome. For animals, the primary barcode marker is a 648-base-pair segment of cy...