DNA typing: an accessory evidence in doping control

A clear positive case for anabolic steroids doping was confounded by alleged urine tampering during doping control procedures. Review of the chain of custody showed no flaws, but nevertheless the athlete was adamant that the urine sample should be analyzed for DNA in order to support her contention that she was not the donor of the sample. The results obtained showed that the urine sample that scored positive for steroids contained nuclear DNA that could not be matched to the DNA obtained from the athlete's blood. On the other hand, the same urine sample contained mitochondrial DNA whose nucleotide sequences spanning the hyper variable regions HV1 and HV2 proved to be identical to those determined in mitochondrial DNA amplified from the athlete's blood. The occurrence of an extraneous genotype is compatible with exogenous nuclear DNA admixture to the athlete's urine. Alternatively, taking in consideration the mitochondrial DNA, we could not exclude that a sibling or a maternal relative of the athlete could have acted as a donor of the urine utilized for doping control and DNA analysis. Both situations point to possible tampering of the urine by the athlete. Adjudication at CAS maintained previous national and international federation decision that there was no proof of a chain of custody flaw to justify the athlete's allegation of urine substitution after collection.     

Genetic variability of 16 Y-chromosome STRs in a sample from Equatorial Guinea (Central Africa)

Nine Y-STR loci from the "minimal haplotype" included in Y-STR Haplotype Reference Databases (YHRD) together with eight additional Y-STRs (DYS437, DYS438, DYS439, DYS460, DYS461, GATA C4, GATA H4 and GATA A10) were analyzed in a sample of 101 males from Equatorial Guinea living in Madrid. Haplotype and allelic frequencies were calculated and genetic diversities were estimated for each genetic system as well as for the whole haplotype. An unexpected high frequency (6%) of intermediate alleles (13.2 and 14.2) was found in DYS385. For DYS19, two alleles were found in one sample. Another sample failed to amplify with DYS393 primers using either PowerPlex Y System (Promega Corporation) or the Y-PLEXtrade mark 12 (Reliagene, New Orleans, LA) commercial kits. Comparison between Equatorial Guinea and another African population (Mozambique; South East Coast) revealed a significant pairwise Phi(st) value between them (Phi(st)=0.03309; P=0.00000).     

Y-chromosomal STR haplotypes in three ethnic groups and one cosmopolitan population from Tunisia

The 11 Y-chromosomal short tandem repeats (STRs) included in the Promega Corporation PowerPlex Y System (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438 and DYS439) were typed in three ethnic groups ("Andalusians", Berber and Arab) and one cosmopolitan population (Tunis) from Tunisia, summing up 247 individuals, and 139 different haplotypes. Focusing the analysis on the seven Y-STRs of the YHRD Minimal Haplotype Core (DYS385 excepted), "Andalusians" showed no differences from the Cosmopolitan and the Arab samples previously published (our Arab sample presented an extremely low haplotype diversity), but were different from the Berbers. The Berbers from Tunisia were not different from those from Morocco.     

Mitochondrial DNA error prophylaxis: assessing the causes of errors in the GEP'02-03 proficiency testing trial

A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.     

STR analysis of artificially degraded DNA-results of a collaborative European exercise

Degradation of human DNA extracted from forensic stains is, in most cases, the result of a natural process due to the exposure of the stain samples to the environment. Experiences with degraded DNA from casework samples show that every sample may exhibit different properties in this respect, and that it is difficult to systematically assess the performance of routinely used typing systems for the analysis of degraded DNA samples. Using a batch of artificially degraded DNA with an average fragment size of approx. 200 bp a collaborative exercise was carried out among 38 forensic laboratories from 17 European countries. The results were assessed according to correct allele detection, peak height and balance as well as the occurrence of artefacts. A number of common problems were identified based on these results such as strong peak imbalance in heterozygous genotypes for the larger short tandem repeat (STR) fragments after increased PCR cycle numbers, artefact signals and allelic drop-out. Based on the observations, strategies are discussed to overcome these problems. The strategies include careful balancing of the amount of template DNA and the PCR cycle numbers, the reaction volume and the amount of Taq polymerase. Furthermore, a careful evaluation of the results of the fragment analysis and of automated allele calling is necessary to identify the correct alleles and avoid artefacts.     

Social perception of rape: how rape myth acceptance modulates the influence of situational factors

This study assessed the role of rape myth acceptance (RMA) and situational factors in the perception of three different rape scenarios (date rape, marital rape, and stranger rape). One hundred and eighty-two psychology undergraduates were asked to emit four judgements about each rape situation: victim responsibility, perpetrator responsibility, intensity of trauma, and likelihood to report the crime to the police. It was hypothesized that neither RMA nor situational factors alone can explain how rape is perceived; it is the interaction between these two factors that best account for social reactions to sexual aggression. The results generally supported the authors' hypothesis: Victim blame, estimation of trauma, and the likelihood of reporting the crime to the police were best explained by the interaction between observer characteristics, such as RMA, and situational clues. That is, the less stereotypic the rape situation was, the greater was the influence of attitudes toward rape on attributions.     

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.