Application of partial Cytochrome b and 12S rRNA Genes for Mammalian species identification

Abstract

Determination of species from wildlife specimens is one of the prime goals of forensic laboratories analyzing samples involved in wildlife crimes. The conviction rate in wildlife crimes is often low due to a lack of evidential support in identification of the species involved in crime. When species identification by application of morphological techniques fails due to sample autolysis or lack of anatomical markers in wildlife specimens, DNA analysis provides the vital, foolproof cue. Sequences generated from mitochondrial DNA regions are used to determine the species by matching against a known reference sequence, either using the global GenBank database or using references created locally. The present study employed species identification by DNA analysis using wildlife samples received from the Forest Department across Tamil Nadu, India. The study demonstrates the utility of partial Cytb and 12S rRNAgenes for determination of species from 18 samples without recognizable morphological features, including tissue, hair and blood. The species of the collected specimens were correctly identified by sequence similarity search with 99 to 100% match and taxonomic classification using phylogenetic tree reconstruction. Of the 18 samples analyzed, accurate species identification using 12S rRNA gene was possible for all the samples, while Cytbgene-based identification was successful for 16 samples. Sequences generated from the study could also serve as a local genetic databank for the State Forest Department to match against sequences from wildlife forensic samples referred to the Institute for ascertaining species involved in wildlife trade. The sequences will also be useful to bridge gaps in genetic data on species native to Tamil Nadu.