A method to identify a large number of mammalian species in the UK from trace samples and mixtures without the use of sequencing

There is no standard test to identify the species of origin of a sample. A general method is to amplify part of the mitochondrial genome, generally the 12S, 16S or cytochrome b gene, and sequence it for comparison with known sequences on GenBank. Highly degraded samples and mixtures make this technique unsuitable.

As a functioning protein, cytochrome b cannot mutate unconditionally. Detrimental changes in the amino acid sequence or composition will result in cell death and would not be passed on to offspring. By examining the cytochrome b sequences non-detrimental variation can be found which can be used for specific-species identification. Areas of high homology can also be identified for universal amplification sites.

Species-specific primers have been developed based on these SNPs in the cytochrome b gene such that they will only react for a particular species. By combining universal priming sites with species-specific sites, a simple yet effect test has been constructed for the identification of species. This test will produce a product of a particular size for each species. It will work on mixtures and has sensitivity to the femtogramme (10−15 g) level.