A Grass Molecular Identification System for Forensic Botany: A Critical Evaluation of the Strengths and Limitations
Plant material is frequently encountered in criminal investigations but often overlooked as potential evidence. We designed a DNA-based molecular identification system for 100 Australian grasses that consisted of a series of polymerase chain reaction assays that enabled the progressive identification of grasses to different taxonomic levels. The identification system was based on DNA sequence variation at four chloroplast and two mitochondrial loci. Seventeen informative indels and 68 single-nucleotide polymorphisms were utilized as molecular markers for subfamily to species-level identification. To identify an unknown sample to subfamily level required a minimum of four markers or nine markers for species identification. The accuracy of the system was confirmed by blind tests. We have demonstrated “proof of concept” of a molecular identification system for trace botanical samples. Our evaluation suggests that the adoption of a system that combines this approach with DNA sequencing could assist the morphological identification of grasses found as forensic evidence.
Keywords: chloroplast DNA; forensic botany; forensic science; grasses; indels; mitochondrial DNA; molecular identification system; polymerase chain reaction; single nucleotide polymorphisms; species identification
Document Type: Research Article
Affiliations: 1: National Manager, Forensic and Data Centres, Australian Federal Police, GPO Box 401, Canberra, ACT 2601, Australia. 2: School of Botany and Zoology, The Australian National University, Canberra, ACT 0200, Australia.
Publication date: November 1, 2009