A molecular identification system for grasses: a novel technology for forensic botany

Area of Science:

• Forensic Science
• Molecular Biology
• Botany

Background:

• Accurate identification of botanical trace evidence is crucial for forensic investigations.
• Grasses are common forensic trace evidence, offering links between crime scenes and individuals.
• Current identification methods are often slow, inaccurate, and costly, hindering routine forensic botany.

Purpose of the Study:

• To develop and evaluate a molecular DNA-based identification system for grasses using Polymerase Chain Reaction (PCR) assays.
• To identify informative indels in the grass mitochondrial genome for taxonomic discrimination.
• To assess the feasibility of a PCR-based system for routine forensic grass identification.

Main Methods:

• Design and testing of five PCR assays targeting specific indels in the grass mitochondrial genome.
• Validation of assays using a control set of 20 phylogenetically representative grass samples.
• Blind testing of the PCR assays on 25 unknown grass samples for identification accuracy.

Main Results:

• The five PCR primer combinations produced expected results for the control set.
• In blind tests, 25 unknown grass samples were identified with high accuracy to genus and tribe.
• The system could confidently exclude samples from certain tribes and genera when specific assays were not designed.

Conclusions:

• The developed PCR assays are effective for identifying grass trace evidence.
• This molecular approach demonstrates the feasibility of a robust grass identification system for forensic applications.
• The system enhances the potential for routine application of forensic botany in investigations.