Mini-Barcode
Definition
A short DNA barcode amplicon (typically 100-250 bp) designed for use when template DNA is fragmented by drying, heat, or age. Standard COI and cytochrome b barcodes (600-700 bp) often fail on degraded fin tissue; mini-barcodes are more reliably amplified.
- Amplicon length
- About 100 to 250 bp
- Standard barcode length
- 600 to 700 bp (COI, cytochrome b)
- Use case
- Dried, heat-treated, or otherwise degraded tissue
- Field
- Shark and ray product identification
Common questions
Why does a shorter amplicon succeed where the full barcode fails?+
Degraded DNA breaks into progressively shorter fragments, and PCR can only amplify a target if an intact stretch of that length survives; a shorter mini-barcode target has a much higher chance of finding an unbroken template than a 600 to 700 bp region.
Does shortening the barcode reduce its species-identification power?+
It reduces the amount of sequence available for comparison, which can occasionally limit discrimination between very closely related species, but validated mini-barcode regions are chosen specifically because they retain enough variable sites to identify species reliably despite the shorter length.
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...
- Ceratotrichia
- Flexible, unsegmented cartilaginous rods that form the internal skeleton of elasmobranch fins. Their number, branching pattern, and cross-sectional morphology are species-informative and...
- CITES Appendix II
- A listing that allows commercial international trade in a species but requires export permits certifying legal and sustainable acquisition. Non-detriment findings (NDFs)...
- 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...
- DNA Barcode
- A short, standardised sequence from a defined locus used to identify a specimen to species by comparison against a curated reference library....
- Elasmobranch
- The subclass containing sharks, skates, and rays, all characterized by a cartilaginous rather than bony skeleton. Forensic identification methods specific to this...
- ElePhant Database
- A curated STR reference database for African savanna and forest elephants and Asian elephants, used to assign ivory to individual animals or...
- Fin Spine
- A stiff calcified spine present anterior to the dorsal fins in many shark species (notably spiny dogfish, Squalus acanthias). Spine presence, shape,...
- 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...
- Vertebral Age Rings
- Paired light and dark bands deposited in shark vertebrae in a manner analogous to tree rings. Counting band pairs under transmitted or...
Explained in these topics
- DNA Barcoding, STR Profiling, and Individual IdentificationA 100-200 bp sub-region of the COI locus amplified when DNA is too degraded for the full 648 bp amplicon. Shorter target length improves recovery from heat-tre...
- Shark and Ray Product Identification