TY - JOUR
T1 - A molecular identification system for grasses
T2 - A novel technology for forensic botany
AU - Ward, J.
AU - Peakall, R.
AU - Gilmore, S. R.
AU - Robertson, J.
PY - 2005/6/10
Y1 - 2005/6/10
N2 - Our present inability to rapidly, accurately and cost-effectively identify trace botanical evidence remains the major impediment to the routine application of forensic botany. Grasses are amongst the most likely plant species encountered as forensic trace evidence and have the potential to provide links between crime scenes and individuals or other vital crime scene information. We are designing a molecular DNA-based identification system for grasses consisting of several PCR assays that, like a traditional morphological taxonomic key, provide criteria that progressively identify an unknown grass sample to a given taxonomic rank. In a prior study of DNA sequences across 20 phylogenetically representative grass species, we identified a series of potentially informative indels in the grass mitochondrial genome. In this study we designed and tested five PCR assays spanning these indels and assessed the feasibility of these assays to aid identification of unknown grass samples. We confirmed that for our control set of 20 samples, on which the design of the PCR assays was based, the five primer combinations produced the expected results. Using these PCR assays in a 'blind test', we were able to identify 25 unknown grass samples with some restrictions. Species belonging to genera represented in our control set were all correctly identified to genus with one exception. Similarly, genera belonging to tribes in the control set were correctly identified to the tribal level. Finally, for those samples for which neither the tribal or genus specific PCR assays were designed, we could confidently exclude these samples from belonging to certain tribes and genera. The results confirmed the utility of the PCR assays and the feasibility of developing a robust full-scale usable grass identification system for forensic purposes.
AB - Our present inability to rapidly, accurately and cost-effectively identify trace botanical evidence remains the major impediment to the routine application of forensic botany. Grasses are amongst the most likely plant species encountered as forensic trace evidence and have the potential to provide links between crime scenes and individuals or other vital crime scene information. We are designing a molecular DNA-based identification system for grasses consisting of several PCR assays that, like a traditional morphological taxonomic key, provide criteria that progressively identify an unknown grass sample to a given taxonomic rank. In a prior study of DNA sequences across 20 phylogenetically representative grass species, we identified a series of potentially informative indels in the grass mitochondrial genome. In this study we designed and tested five PCR assays spanning these indels and assessed the feasibility of these assays to aid identification of unknown grass samples. We confirmed that for our control set of 20 samples, on which the design of the PCR assays was based, the five primer combinations produced the expected results. Using these PCR assays in a 'blind test', we were able to identify 25 unknown grass samples with some restrictions. Species belonging to genera represented in our control set were all correctly identified to genus with one exception. Similarly, genera belonging to tribes in the control set were correctly identified to the tribal level. Finally, for those samples for which neither the tribal or genus specific PCR assays were designed, we could confidently exclude these samples from belonging to certain tribes and genera. The results confirmed the utility of the PCR assays and the feasibility of developing a robust full-scale usable grass identification system for forensic purposes.
KW - Forensic botany
KW - Grasses
KW - Indels
KW - Mitochondrial genome
KW - Molecular identification system
KW - PCR assay
UR - http://www.scopus.com/inward/record.url?scp=20544434098&partnerID=8YFLogxK
U2 - 10.1016/j.forsciint.2004.07.015
DO - 10.1016/j.forsciint.2004.07.015
M3 - Article
C2 - 15978338
AN - SCOPUS:20544434098
SN - 0379-0738
VL - 152
SP - 121
EP - 131
JO - Forensic Science International
JF - Forensic Science International
IS - 2-3
ER -