Forensic identification of internal transcribed spacer region-targeting plant and fungal species by direct sequencing

Abstract

 Species identification of botanical and fungal evidences offer beneficial information in crime investigation. As these biological species are highly diverse and complex, their DNA sequence analysis is effective in the field of forensic science. In this study, the internal transcribed spacer (ITS) region on the ribosomal DNA of plant and fungal samples was examined as a targeting locus. For 30 plant and 9 fungal samples, direct sequencing was performed for both ITS1 and ITS2 region using modified universal primers and M13 tag primers. Each resulting sequence was evaluated by a nucleotide BLAST homology search. The top hits for sequence homology against each sample matched the actual species with almost 100% identity. However, homology search does not always result in sequence similarity/identity among closely-related species; therefore, results of homology search must be carefully assessed.