Bayesian Barcoding Inference
Definition
A method for assigning a DNA barcode sequence to a species that uses prior probabilities (the known composition of species in a trade network) and a likelihood function (how well the sequence fits reference data for each candidate species) to produce a posterior probability of species identity.
- Field
- DNA barcode species identification
- Inputs
- Prior probabilities and a likelihood function
- Prior source
- Known species composition of a trade network
- Output
- Posterior probability of species identity
Common questions
Why bring in a trade-network prior rather than relying on the sequence match alone?+
A raw sequence match can be ambiguous between closely related species with similar barcodes, so weighting candidate species by how commonly they actually appear in the relevant trade, such as wildlife trafficking or timber trade, sharpens the identification when the genetic evidence alone is inconclusive.
What is the risk of using a poorly chosen prior in this method?+
If the assumed trade composition is inaccurate or based on outdated survey data, the posterior probability will be biased toward whatever species the prior favoured, so the prior itself needs to be defensible and disclosed rather than treated as a neutral input.
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