Real-time PCR designs to estimate nuclear and mitochondrial DNA copy number in forensic and ancient DNA studies

We explore different designs to estimate both nuclear and mitochondrial human DNA (mtDNA) content based on the detection of the 5' nuclease activity of the Taq DNA polymerase using fluorogenic probes and a real-time quantitative PCR detection system. Human mtDNA quantification was accomplished by monitoring the real-time progress of the PCR-amplification of two different fragment sizes (113 and 287 bp) within the hypervariable region I (HV1) of the mtDNA control region, using two fluorogenic probes to specifically determine the mtDNA copy of each fragment size category. This mtDNA real-time PCR design has been used to assess the mtDNA preservation (copy number and degradation state) of DNA samples retrieved from 500 to 1500 years old human remains that showed low copy number and highly degraded mtDNA. The quantification of nuclear DNA was achieved by real-time PCR of a segment of the X-Y homologous amelogenin (AMG) gene that allowed the simultaneous estimation of a Y-specific fragment (AMGY: 112 bp) and a X-specific fragment (AMGX: 106 bp) making possible not only haploid or diploid DNA quantitation but also sex determination. The AMG real-time PCR design has been used to quantify a set of 57 DNA samples from 4-5 years old forensic bone remains with improved sensitivity compared with the slot-blot hybridization method. The potential utility of this technology to improve the quality of some PCR-based forensic and ancient DNA studies (microsatellite typing and mtDNA sequencing) is discussed.     

The murderer is the bed: an unusual case of death by traumatic asphyxia in a hotel folding bunk bed

This paper presents the first referenced case on a death by traumatic asphyxia in a folding bunk bed. A middle-aged man was found dead in a hotel room trapped into a lower folding bunk bed where he had been sleeping after a party. The autopsy showed signs of asphyxia and excluded signs of struggle and sexual intercourse. Toxicological analyses revealed alcohol intoxication. A differential diagnosis of the manner of death including a technical study of the bed which contributed to understand the circumstances of death was made. The medico-legal investigation of the case strongly supported the hypothesis of an accidental death by traumatic asphyxia.     

Searching the Soil: Forensic Importance of Edaphic Fauna After the Removal of a Corpse

Abstract: Arthropods at different stages of development collected from human remains in an advanced stage of decomposition (following autopsy) and from the soil at the scene are reported. The corpse was found in a mixed deciduous forest of Biscay (northern Spain). Soil fauna was extracted by sieving the soil where the corpse lay and placing the remains in Berlese–Tullgren funnels. Necrophagous fauna on the human remains was dominated by the fly Piophilidae: Stearibia nigriceps (Meigen, 1826), mites Ascidae: Proctolaelaps epuraeae (Hirschmann, 1963), Laelapidae: Hypoaspis (Gaeolaelaps) aculeifer (Canestrini, 1884), and the beetle Cleridae: Necrobia rufipes (de Geer, 1775). We confirm the importance of edaphic fauna, especially if the deceased is discovered in natural environs. Related fauna may remain for days after corpse removal and reveal information related to the circumstances of death. The species Nitidulidae: Omosita depressa (Linnaeus, 1758), Acaridae: Sancassania berlesei (Michael, 1903), Ascidae: Zerconopsis remiger (Kramer, 1876) and P. epuraeae, Urodinychidae: Uroobovella pulchella (Berlese, 1904), and Macrochelidae: Glyptholaspis americana (Berlese, 1888) were recorded for the first time in the Iberian Peninsula.     

Acculturation,Gender, Depression,and Cigarette Smoking Among U.S. Hispanic Youth: The Mediating Role of Perceived Discrimination

Hispanic youth are at risk for experiencing depressive symptoms and smoking cigarettes, and risk for depressive symptoms and cigarette use increase as Hispanic youth acculturate to U.S. culture. The mechanism by which acculturation leads to symptoms of depression and cigarette smoking is not well understood. The present study examined whether perceived discrimination explained the associations of acculturation with depressive symptoms and cigarette smoking among 1,124 Hispanic youth (54% female). Youth in Southern California completed surveys in 9th–11th grade. Separate analyses by gender showed that perceived discrimination explained the relationship between acculturation and depressive symptoms for girls only. There was also evidence that discrimination explained the relationship between acculturation and cigarette smoking among girls, but the effect was only marginally significant. Acculturation was associated with depressive symptoms and smoking among girls only. Perceived discrimination predicted depressive symptoms in both genders, and discrimination was positively associated with cigarette smoking for girls but not boys. These results support the notion that, although Hispanic boys and girls experience acculturation and discrimination, their mental health and smoking behaviors are differentially affected by these experiences. Moreover, the results indicate that acculturation, gender, and discrimination are important factors to consider when addressing Hispanic youth’s mental health and substance use behaviors.     

Eyewitness testimony of children in target-present and target-absent lineups

The effects of age of witness and age of suspect on eyewitness testimony were investigated. Forty-eight elementary school children and 48 college students viewed a slide sequence of a mock crime. This was followed by target-present or target-absent photo identification with a no-choice option, central and peripheral questions related to the crime, and a second photo identification. In photo identification, child witnesses had a higher rate of choosing than adult witnesses, suggesting that children have more lax criteria of responding. The accuracy data showed similar levels of sensitivity across ages although there was a trend toward reduced accuracy of child witnesses in target-absent lineups. All witnesses made more total choices and more correct rejections with child-suspect lineups than adult-suspect lineups. Central questions were answered better than peripheral questions by both age groups, but adults made significantly more “don't know” choices.     

The 2000-2001 GEP-ISFG Collaborative Exercise on mtDNA: assessing the cause of unsuccessful mtDNA PCR amplification of hair shaft samples

We report the results of Spanish and Portuguese working group (GEP) of International Society of Forensic Genetics (ISFG) Collaborative Exercise 2001-2002 on mitochondrial DNA (mtDNA) analysis. 64 laboratories from Spain, Portugal and several Latin-American countries participated in this quality control exercise. Five samples were sent to the participating laboratories, four blood stains (M1-M4) and a sample (M5) consisting of two hair shaft fragments. M4 was non-human (Felis catus) in origin; therefore, the capacity of the labs to identify the biological source of this sample was an integral part of the exercise. Some labs detected the non-human origin of M4 by carrying out immuno-diffussion techniques using antihuman serum, whereas others identified the specific animal origin by testing the sample against a set of animal antibodies or by means of the analysis of mtDNA regions (Cyt-b, 12S, and 16S genes). The results of the other three human blood stains (M1-M3) improved in relation to the last Collaborative Exercises but those related to hairs yielded a low rate of success which clearly contrasts with previous results. As a consequence of this, some labs performed additional analysis showing that the origin of this low efficiency was not the presence of inhibitors, but the low quantity of DNA present in these specific hair samples and the degradation.As a general conclusion the results emphasize the need of external proficiency testing as part of the accreditation procedure for the labs performing mtDNA analysis in forensic casework.     

Results of the GEP-ISFG collaborative study on the Y chromosome STRs GATA A10, GATA C4, GATA H4, DYS437, DYS438, DYS439, DYS460 and DYS461: population data

The Spanish and Portuguese ISFG Working Group (GEP-ISFG) carried out a collaborative exercise in order to asses the performance of two Y chromosome STR tetraplexes, which include the loci DYS461, GATA C4, DYS437 and DYS438 (GEPY I), and DYS460, GATA A10, GATA H4 and DYS439 (GEPY II). The groups that reported correct results in all the systems were also asked to analyse a population sample in order to evaluate the informative content of these STRs in different populations. A total of 1020 males out of 13 population samples from Argentina, Brazil, Costa Rica, Macao, Mozambique, Portugal and Spain were analysed for all the loci included in the present study. Haplotype and allele frequencies of these eight Y-STRs were estimated in all samples. The lowest haplotype diversity was found in the Lara (Argentina) population (95.44%) and the highest (99.90%) in Macao (China). Pairwise haplotype analysis showed the relative homogeneity of the Iberian origin samples, in accordance with what was previously found in the European populations for other Y-STR haplotypes (http://www.ystr.org). As expected, the four non-Caucasian samples, Macao (Chinese), Mozambique (Africans), Costa Rica (Africans) and Argentina (Lara, Amerindians), show highly significant Phist values in the pairwise comparisons with all the Caucasian samples.     

Service Charters: Reshaping Trust in Government—The Case of Spain

Service charters are located at the intersection between public administration reforms and governance initiatives for improving citizen trust in governments. Service charters in Spain show the will to shift from a legal tradition to one that meets citizens' needs and makes government more accessible, transparent, and open to the public. The article examines the role and performance of service charters and the contribution of charters to change in Spanish public administration, to the empowerment of citizens in the improvement of service standards, and to citizen participation in the organization of public services. It aims to investigate the factors that drive the introduction of charters and the performance that can be obtained. To test the potential of service charters in Spain, we interviewed public-sector managers at the central level by applying the Delphi method and statistical techniques.