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Microbial analysis of bite marks by sequence comparison of streptococcal DNA.

Kennedy DM, Stanton JA, García JA, Mason C, Rand CJ, Kieser JA, Tompkins GR - PLoS ONE (2012)

Bottom Line: Bacterial DNA was extracted to provide the template for PCR primers specific for streptococcal 16S ribosomal RNA (16S rRNA) gene, 16S-23S intergenic spacer (ITS) and RNA polymerase beta subunit (rpoB).The probabilities of correctly distinguishing matching and non-matching teeth samples were 0.92 for ITS, 0.99 for 16S rRNA and 1.0 for rpoB.These findings strongly support the tenet that bacterial DNA amplified from bite marks and teeth can provide corroborating information in the identification of assailants.

View Article: PubMed Central - PubMed

Affiliation: Sir John Walsh Research Institute, School of Dentistry, University of Otago, Dunedin, New Zealand.

ABSTRACT
Bite mark injuries often feature in violent crimes. Conventional morphometric methods for the forensic analysis of bite marks involve elements of subjective interpretation that threaten the credibility of this field. Human DNA recovered from bite marks has the highest evidentiary value, however recovery can be compromised by salivary components. This study assessed the feasibility of matching bacterial DNA sequences amplified from experimental bite marks to those obtained from the teeth responsible, with the aim of evaluating the capability of three genomic regions of streptococcal DNA to discriminate between participant samples. Bite mark and teeth swabs were collected from 16 participants. Bacterial DNA was extracted to provide the template for PCR primers specific for streptococcal 16S ribosomal RNA (16S rRNA) gene, 16S-23S intergenic spacer (ITS) and RNA polymerase beta subunit (rpoB). High throughput sequencing (GS FLX 454), followed by stringent quality filtering, generated reads from bite marks for comparison to those generated from teeth samples. For all three regions, the greatest overlaps of identical reads were between bite mark samples and the corresponding teeth samples. The average proportions of reads identical between bite mark and corresponding teeth samples were 0.31, 0.41 and 0.31, and for non-corresponding samples were 0.11, 0.20 and 0.016, for 16S rRNA, ITS and rpoB, respectively. The probabilities of correctly distinguishing matching and non-matching teeth samples were 0.92 for ITS, 0.99 for 16S rRNA and 1.0 for rpoB. These findings strongly support the tenet that bacterial DNA amplified from bite marks and teeth can provide corroborating information in the identification of assailants.

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Related in: MedlinePlus

The effect of single- and multi-locus sequencing on unique read numbers.Comparison of the average number of unique reads generated from samples with varying amounts of DNA, containing either amplicons from one locus or amplicons from four loci.
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pone-0051757-g005: The effect of single- and multi-locus sequencing on unique read numbers.Comparison of the average number of unique reads generated from samples with varying amounts of DNA, containing either amplicons from one locus or amplicons from four loci.

Mentions: The amplicon libraries from the four loci generated from bite mark and teeth samples 1–11 were pooled prior to sequencing. To determine whether single amplicon sequencing enhanced the number of unique reads, five additional bite mark and teeth samples (B/T12-16) were collected and the amplicons sequenced singly (rather than combined as a pool). Under these conditions, the number of unique reads (remaining after filtering) was generally greater than from samples in which the loci were pooled (Figure 5). Furthermore, submitting higher amounts of DNA for sequencing also increased the average number of unique reads.


Microbial analysis of bite marks by sequence comparison of streptococcal DNA.

Kennedy DM, Stanton JA, García JA, Mason C, Rand CJ, Kieser JA, Tompkins GR - PLoS ONE (2012)

The effect of single- and multi-locus sequencing on unique read numbers.Comparison of the average number of unique reads generated from samples with varying amounts of DNA, containing either amplicons from one locus or amplicons from four loci.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3526645&req=5

pone-0051757-g005: The effect of single- and multi-locus sequencing on unique read numbers.Comparison of the average number of unique reads generated from samples with varying amounts of DNA, containing either amplicons from one locus or amplicons from four loci.
Mentions: The amplicon libraries from the four loci generated from bite mark and teeth samples 1–11 were pooled prior to sequencing. To determine whether single amplicon sequencing enhanced the number of unique reads, five additional bite mark and teeth samples (B/T12-16) were collected and the amplicons sequenced singly (rather than combined as a pool). Under these conditions, the number of unique reads (remaining after filtering) was generally greater than from samples in which the loci were pooled (Figure 5). Furthermore, submitting higher amounts of DNA for sequencing also increased the average number of unique reads.

Bottom Line: Bacterial DNA was extracted to provide the template for PCR primers specific for streptococcal 16S ribosomal RNA (16S rRNA) gene, 16S-23S intergenic spacer (ITS) and RNA polymerase beta subunit (rpoB).The probabilities of correctly distinguishing matching and non-matching teeth samples were 0.92 for ITS, 0.99 for 16S rRNA and 1.0 for rpoB.These findings strongly support the tenet that bacterial DNA amplified from bite marks and teeth can provide corroborating information in the identification of assailants.

View Article: PubMed Central - PubMed

Affiliation: Sir John Walsh Research Institute, School of Dentistry, University of Otago, Dunedin, New Zealand.

ABSTRACT
Bite mark injuries often feature in violent crimes. Conventional morphometric methods for the forensic analysis of bite marks involve elements of subjective interpretation that threaten the credibility of this field. Human DNA recovered from bite marks has the highest evidentiary value, however recovery can be compromised by salivary components. This study assessed the feasibility of matching bacterial DNA sequences amplified from experimental bite marks to those obtained from the teeth responsible, with the aim of evaluating the capability of three genomic regions of streptococcal DNA to discriminate between participant samples. Bite mark and teeth swabs were collected from 16 participants. Bacterial DNA was extracted to provide the template for PCR primers specific for streptococcal 16S ribosomal RNA (16S rRNA) gene, 16S-23S intergenic spacer (ITS) and RNA polymerase beta subunit (rpoB). High throughput sequencing (GS FLX 454), followed by stringent quality filtering, generated reads from bite marks for comparison to those generated from teeth samples. For all three regions, the greatest overlaps of identical reads were between bite mark samples and the corresponding teeth samples. The average proportions of reads identical between bite mark and corresponding teeth samples were 0.31, 0.41 and 0.31, and for non-corresponding samples were 0.11, 0.20 and 0.016, for 16S rRNA, ITS and rpoB, respectively. The probabilities of correctly distinguishing matching and non-matching teeth samples were 0.92 for ITS, 0.99 for 16S rRNA and 1.0 for rpoB. These findings strongly support the tenet that bacterial DNA amplified from bite marks and teeth can provide corroborating information in the identification of assailants.

Show MeSH
Related in: MedlinePlus