eDNA Meta-Barcoding
Definition
Environmental DNA analysis using PCR amplification of a target gene region from a complex environmental sample (water, soil), followed by high-throughput sequencing and bioinformatic assignment of reads to taxa. Applied to diatom testing using the 18S rRNA gene to generate a species-composition profile from water and bone-marrow digests.
- Method
- PCR amplification plus high-throughput sequencing
- Target gene example
- 18S rRNA gene for diatom testing
- Sample types
- Water and bone-marrow digests
- Output
- Species-composition profile
Common questions
Why is eDNA meta-barcoding useful for the diatom test in suspected drowning?+
Rather than relying on morphological identification of diatoms under a microscope, sequencing the 18S rRNA region from bone marrow and the suspected drowning water gives a species-composition profile that can be compared directly, strengthening the link between the body and the water source.
How does meta-barcoding differ from single-species eDNA testing?+
Single-species eDNA testing targets one known species with a specific primer, while meta-barcoding amplifies a broad marker region shared across many taxa and then sorts the resulting sequence reads by taxon, revealing an entire community composition from one sample.
Related terms
- Diatom Test
- A laboratory test for ante-mortem submersion in which bone marrow (from sealed femur diaphysis) is acid-digested and the diatom species identified in...
- Frustule
- The silica cell wall of a diatom, composed of two overlapping valves (epitheca and hypotheca). Frustules are taxonomically distinctive, chemically resistant to...
- matK
- Maturase K gene, located in the chloroplast trnK intron. The second CBOL-approved plant barcode marker, with an approximately 870 bp diagnostic amplicon....
- RAPD (Randomly Amplified Polymorphic DNA)
- A PCR technique using short arbitrary primers (8-10 bases) that bind at multiple sites across a genome, generating a fingerprint pattern of...
- 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...
- Sporopollenin
- The highly chemically inert polymer forming the outer wall (exine) of pollen grains and spores. Resistant to acid, alkali, oxidation, and biological...