The forensic identification and population monitoring of animal species would benefit greatly from a reliable DNA test. To this end the Forensic Science Service has broadened the range of UK terrestrial mammals within the reference library for which species-specific cytochrome b DNA sequences have been verified. This gene is ideal for species identification as it shows limited variability within and much greater variation between species. By identifying regions of the gene sequence unique to each species a positive identification of any material containing DNA can be made. DNA can be used to determine the source of shed hairs and faeces amongst other items that might indicate the presence of an organism within the environment. The sequence data together with authenticated tissue and DNA samples will provide an invaluable resource in exploring the feasibility of DNA testing as a tool for the surveillance of British mammals. This study also provides the necessary groundwork for developing rapid and cost-effective hair identification tests in the future that may be capable of identifying species from a single shed hair.

 

Cytochrome b gene DNA sequences were derived from 28 mammal species using specimens supplied by the Joint Nature Conservation Committee (JNCC). Where possible samples were collected from diverse geographic locations and their sequences compared with published data from the GenBank internet database. Sequence data was derived by replicating overlapping fragments of the DNA code from tissue and hair samples from individual animals. DNA sequence variation between individuals was negligible in some species and extreme in others, often revealing variability unreported in the published literature. Although most variation appeared to result from authentic differences between individuals, several species showed evidence of nuclear copies of the cytochrome b gene. These alternative sequences located within the cell nucleus rather than the mitochondria have been unwittingly reported in previous studies and are a potential major source of confusion in the development and use of DNA tests for species identification.