Enhanced kinship analysis and STR-based DNA typing for human identification in mass fatality incidents: the Swissair flight 111 disaster

A bioinformatic tool was developed to assist with the victim identification initiative that followed the Swissair Flight 111 disaster. Making use of short tandem repeat (STR) DNA typing data generated with AmpFlSTR Profiler Plus (PP) and AmpFlSTR COfiler(CO) kits, the software systematically compared each available STR genotype with every other genotype. The matching algorithm was based on the search for: (i) direct matches to genotypes derived from personal effects; and (ii) potential kinship associations between victims and next-of-kin, as measured by allele sharing at individual loci. The software greatly assisted parentage analysis by enabling kinship evaluation in situations where complete parentage trios were unavailable and, in some situations, with distantly related relatives. Exclusion of fortuitous kinship associations (FKA) was made possible through the recovery at the disaster site of at least one remains for every sought-after victim, and was incorporated into the kinship software. The data from the 13 combined STR loci produced 6 and 23 times fewer FKAs when compared with PP alone and AmpFlSTR Profiler (PR) alone, respectively. Identification leads or confirmations of identification were obtained for 218 victims for which DNA reference samples (personal effects and kin) had been submitted. Confirmation of an inferred kinship association was sought through frequency and likelihood calculations, as well as corroborative data from other identification modalities. The use of a simple, yet powerful, automated genotype comparison approach and the use of megaplexes with high power of discrimination (PD) values extended considerably the identification capabilities in the case of the Swissair disaster. The DNA typing identification modality proved to be a valuable component of the large arsenal of identification tools deployed in the aftermath of this disaster.     

Systematic analysis of stutter percentages and allele peak height and peak area ratios at heterozygous STR loci for forensic casework and database samples

To assist the interpretation of STR DNA typing results from forensic casework samples containing mixtures, the range of heterozygous allele peak height and peak area ratios (HR) and stutter percentages (stutter %) for the loci comprised in the AmpFlSTR Profiler Plus (PP) kit were assessed on 468 database and 275 casework single source samples. Stutter % medians were similar for database and casework samples, ranging from 2% to 7%. The upper limit of the stutter value range was 16%, calculated as median +3 SD, although lower locus-specific values could be used. HR medians were 93 +/- 6.5% for database samples, 88 +/- 12% for casework samples. For casework samples, the maximum signal imbalance noted was 52%, calculated as median -3 SD. No significant difference was observed between peak height and peak area calculated values. This study shows the importance of selecting the proper reference database for the establishment of HR threshold values.     

The evaluation of the extent of transporting or "tracking" an identifiable ignitable liquid (gasoline) throughout fire scenes during the investigative process

Tests have determined that boots or shoes of individuals at a fire scene do not transport sufficient contaminants ("tracking") through the fire scene to produce a positive laboratory result for the presence of gasoline in a fire scene that was not present at the time of the fire. Questions about the validity of forensic laboratory results have been raised on the basis that low-level gasoline residues detected in the laboratory samples could have been the result of transporting the residue by footwear contaminated from the fire scene ("tracking"). The data collected in this study establish that "tracking" does not lead to false-positive laboratory results. Canines trained and experienced in the detection of trace ignitable liquid residues were also utilized in this study. The canine results confirmed that properly trained canines show a higher sensitivity than do standard ASTM laboratory techniques for fire debris analysis. In a few cases, canines responded to contamination, but laboratory testing (which is the definitive indicator) did not produce positive results.     

Differentiation of black gel inks using optical and chemical techniques

Gel ink pens have become a common writing instrument in the United States. Questioned document examiners often attempt to optically differentiate gel inks from each other and from other non-ballpoint ink writings (e.g., those from roller-ball pens). Since early formulations were primarily pigment-based, they do not elute when analyzed by thin-layer chromatography. However, recent gel ink formulations (i.e., within the past five years) include dye-based inks that can be easily separated. This study differentiates black gel inks using optical and chemical techniques. The techniques include: microscopy, visible and near infrared reflectance, near infrared luminescence, thin-layer chromatography (TLC), spot tests, and gas chromatography/mass spectrometry (GC/MS). As a result of this study a flow chart has been developed allowing for a systematic determination of a questioned ink. In addition, an analysis of volatile compounds found in gel inks revealed that there are some unique ingredients that may be found in gel inks that are not typically found in other non-ballpoint inks.     

Organic explosives analysis using on column-ion trap EI/NICI GC-MS with an external source

In this study, a standard method by gas chromatography coupled with mass spectrometry (GC/MS) for the analysis of classical organic explosives was developed. This method was validated in the EI mode, based on the XPT 90-210 standard method. Detection limits (LOD) and quantitation limits (LOQ) were both determined using electronic impact (EI) and negative ion chemical ionization (NICI) modes. These were compared and results showed that in the NICI mode, detection limits were lower than in the EI mode, thus NICI mode appeared to be the best way to analyze nitrate esters. Results of ion trap MS detection were then compared with those obtained in a previous study with single quadrupolar technology. Major ions that were obtained using ion trap MS detection in these two modes were reported.     

The forensic medical diagnosis of intoxication of alcohol surrogates by morphological findings

The pathomorphology of intoxication of alcohol surrogates is described. A high frequency rate of DIC-syndrome is shown for the condition. A majority of thrombi accumulates at places with the highest concentrations of toxic substances as well as at those places, through which poisoning substances are brought out of the body, i.e. in the liver (since toxic substances are introduced perorally) and kidneys. Thrombi were detected in all internals, including the brain, in lethal intoxication. The immediate toxic effect from methanol and from higher spirits can matter in the genesis of changes, including acute swelling and chromatolysis with subsequent cell death. Exclusively cerebral or coagulopathic-cerebral types of thanatogenesis were registered in studied case of intoxication.     

Polymorphism of the central region of D-loop of mitochondrial DNA and personality identification by forensic medicine methods

Polymorphism of mDNA D-loop central region (CR), positions 16366-0072) was studied versus hypervariable sections (HVS1), positions 16024-16365, and HVS2, positions 00073-00340, for a sample of 71 residents of the Russian Federation. Ten polymorphic positions with 56 nucleotide substitutions, 55 of which are transitions, were detect in the CR section; no insertions or deletions were found there. It was proven as possible to use the mDNA CR locus as an additional identification marker in the forensic-expert of the mDNA control region. The probability of random coincidence (RC) of haplotypes in joint typing of HVS1, HVS2 and CR made 0.0208, which is 1.4-fold less versus the same parameter for haplotypes HVS1/HVS2 (RC = 0.0284).     

Allele frequencies data and statistic parameters for 16 STR loci-D19S433, D2S1338, CSF1PO, D16S539, D7S820, D21S11, D18S51, D13S317, D5S818, FGA, Penta E, TH01, vWA, D8S1179, TPOX, D3S1358-in the Rio de Janeiro population, Brazil

Allele frequencies for 16 short tandem repeats (STR) loci were determined with a sample of 230-300 unrelated individuals from the population of Rio de Janeiro, Brazil. The loci are the most commonly used in forensic and paternity testing, being analysed by the Identifiler (Applied Biosystems) and PowerPlex 2.1 (Promega) commercial kits. It was proved that Penta E and D18S51 are the most polymorphic loci.     

The designer drug situation in Ibiza

A total of 137 urine samples and 46 serum samples, corresponding to 154 self-confessed designer drugs consumers in Ibiza island, were analyzed for the presence of designer drugs: amphetamine and amphetamine derivatives (methamphetamine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA), methylenedioxyamphetamine (MDA), p-methoxymethylamphetamine (PMMA), p-methoxyamphetamine (PMA), etc.), ketamine and gamma-hydroxybutyric acid. Among this population, coming both from the forensic clinic and from the emergency room of a hospital, a total of 99 cases were found positive for some designer drug. This study shows the prevalence of methylenedioxymethamphetamine (MDMA) among designer drug users, sole or in association with other drugs. Also, the mixture of MDMA with other designer drugs, ethanol and/or cocaine is shown to be more likely to produce toxic symptoms requiring clinical attendance in a hospital emergency room. These findings along with the consumption history, the concentrations of drugs and metabolites in urine and serum and the toxicological significance for the interpretation of some MDMA metabolites such as 4-hydroxy-3-methoxymethamphetamine (HMMA) are discussed in this study.     

Y-STR polymorphism in Central Anatolian Region of Turkey

Eight Y-chromosome specific STR (Y-STR) loci including DYS19, DYS388, DYS389I, DYS389II, DYS390, DYS391, DYS392 and DYS393 were investigated in a group of males from Central Anatolian Region of Turkey. Healthy 59 males living in this region for at least three generations were included in the study. PCR analysis was carried out with Y-STR specific primers on genomic DNA obtained from peripheral blood samples and size determination of PCR products was performed by silver staining following 6% polyacrylamide gel electrophoresis (PAGE). DYS388 was found to be the locus with lowest diversity (D) whereas DYS389II was the locus with highest diversity. The current study presented a framework of variation for the eight Y-STR loci in Central Anatolian population.