A Ge.F.I. - ISFG European collaborative study on DNA identification of Cannabis sativa samples using a 13-locus multiplex STR method.

Cannabis sativa is the most used controlled substance in Europe. With the advent of new and less restrictive European laws on cannabis sale for recreational use (including in Italy), an increase in indoor cannabis crops were observed. This increase was possible due to the availability of cannabis seeds through the internet market. Genetic identification of cannabis can link seizures and if in possession then might aid in an investigation. A 13-locus multiplex STR method was previously developed and validated by Houston et al. A collaborative exercise was organized by the Italian Forensic Geneticists - International Society of Forensic Genetics (Ge.F.I. - ISFG) Working Group with the aim to test the reproducibility, reliability and robustness of this multiplex cannabis STR kit. Twenty-one laboratories from three European countries participated in the collaborative exercise and were asked to perform STR typing of two cannabis samples. Cannabis DNA samples and the multiplex STR kit were provided by the University of Barcelona and Sam Houston State University. Different platforms for PCR amplification, capillary electrophoresis (CE) and genotyping software were selected at the discretion of the participating laboratories. Although the participating laboratories used different PCR equipment, CE platforms and genotyping software, concordant results were obtained from the majority of the samples. The overall genotyping success ratio was 96%. Only minor artifacts were observed. The mean peak height ratio was estimated to be 76.3% and 78.1% for sample 1 and sample 2, respectively. The lowest amount of -1 / + 1 stutter percentage produced, when the height of the parent allele was higher than 8000 RFU, resulted to be less than 10% of the parent allele height. Few common issues were observed such as a minor peak imbalance in some heterozygous loci, some artifact peaks and few instances of allelic drop-out. The results of this collaborative exercise demonstrated the robustness and applicability of the 13-locus system for cannabis DNA profiling for forensic purposes.

Simultaneous DNA and RNA profiling in a case of sexual assault in a 3-year-old child: Forensic genetics solves the crime.

DNA profiling can identify an individual from a sample of biological material but it does not reveal what body fluid or tissue source the DNA profile originated from. In many cases it is important to know from what body fluid or tissue the DNA profile originated in order to provide crucial information necessary to the investigation, especially in cases where the victims are not able to give information about the dynamics of the event. For this purpose messenger RNA (mRNA) analysis has been shown to be a suitable method for the identification of body fluids, resulting in a trend to overcome the conventional approaches. Here we present the first report about case regarding a three-year-old child supposedly victim of a sexual assault with digital penetration. Thanks to the use of the combined DNA profiling and RNA analysis it was possible to demonstrate the sexual assault suffered by the victim.

A case of suicide by double gunshot wounds to the head: the ability to act after the first shot.

A single gunshot (or multiple) does (do) not necessarily lead to immediate loss of consciousness or rapid neurological deficits, so the victim may be able to repeatedly pull the trigger before achieving the lethal effect. Despite multiple gunshot wounds can lead to the suspicious participation of other person to the death of the victim, in the medico-legal literature suicides with multiple gunshot wounds are reported, demonstrating the ability of the victim to act after two or more gunshots. In this case, a 47-years-old man was found dead in a pool of blood in the kitchen of his house. According to findings and analysis, the victim modified a single-shot, pneumatic toy gun branded "Condor" Cal. 7 mm (a gun that is made mainly with "ZAMAK" zinc-based alloy, designed to shoot one soft-polymer bullet at a time, with an initial kinetic energy lower than 1 Joule) into an improvised firearm weapon. With this gun, the victim achieved shooting of two bullets into his head, both entering from the right temporal region of his head, with one stopped in the left occipital lobe and the other one in the left temporal lobe. His death was caused by cranium-meningo-encephalic gunshot wounds. The conditions supporting the hypothesis that the victim was able to fire two shots to his head before the onset of incapacitation (the type of bullets used, the location of injuries and their consequences) and the characteristics that typically allow to distinguish the manner of death (suicide vs homicide) were evaluated. Based on all the collected elements, it was possible to confirm that suicide was the manner of death. This case underlines the importance of evaluating all available elements (post-mortem imaging, autopsy and toxicological findings, ballistics and neuropathological evaluations) to distinguish suicide from homicide and to prevent incorrect conclusions.

Cyclists fatalities: Forensic remarks regarding 335 cases.

A retrospective study was carried out on post-mortem examination data regarding 335 cyclists involved in fatal accidents along the period 1983-2012. The following variables were considered: temporal data (year, month, day of the week and hour of the day), circumstances of the accident, vehicles involved, victims' features (sex, age), pathological and toxicological findings, cause of death. Most victims were male (77.62%), with a mean age of 58 years. In most cases vehicles other than only bicycles were involved, more frequently cars, followed by heavy motor vehicles. Head was the most frequently body region involved in lethal injuries (65.37%); low extremities were the body district most frequently involved in non-lethal injuries (63.9%). This study confirmed the importance of using helmet; head protection should be a priority for bikers.

Development of an Italian RM Y-STR haplotype database: Results of the 2013 GEFI collaborative exercise.

Recently introduced rapidly mutating Y-chromosomal short tandem repeat (RM Y-STR) loci, displaying a multiple-fold higher mutation rate relative to any other Y-STRs, including those conventionally used in forensic casework, have been demonstrated to improve the resolution of male lineage differentiation and to allow male relative separation usually impossible with standard Y-STRs. However, large and geographically-detailed frequency haplotype databases are required to estimate the statistical weight of RM Y-STR haplotype matches if observed in forensic casework. With this in mind, the Italian Working Group (GEFI) of the International Society for Forensic Genetics launched a collaborative exercise aimed at generating an Italian quality controlled forensic RM Y-STR haplotype database. Overall 1509 male individuals from 13 regional populations covering northern, central and southern areas of the Italian peninsula plus Sicily were collected, including both "rural" and "urban" samples classified according to population density in the sampling area. A subset of individuals was additionally genotyped for Y-STR loci included in the Yfiler and PowerPlex Y23 (PPY23) systems (75% and 62%, respectively), allowing the comparison of RM and conventional Y-STRs. Considering the whole set of 13 RM Y-STRs, 1501 unique haplotypes were observed among the 1509 sampled Italian men with a haplotype diversity of 0.999996, largely superior to Yfiler and PPY23 with 0.999914 and 0.999950, respectively. AMOVA indicated that 99.996% of the haplotype variation was within populations, confirming that genetic-geographic structure is almost undetected by RM Y-STRs. Haplotype sharing among regional Italian populations was not observed at all with the complete set of 13 RM Y-STRs. Haplotype sharing within Italian populations was very rare (0.27% non-unique haplotypes), and lower in urban (0.22%) than rural (0.29%) areas. Additionally, 422 father-son pairs were investigated, and 20.1% of them could be discriminated by the whole set of 13 RM Y-STRs, which was very close to the theoretically expected estimate of 19.5% given the mutation rates of the markers used. Results obtained from a high-coverage Italian haplotype dataset confirm on the regional scale the exceptional ability of RM Y-STRs to resolve male lineages previously observed globally, and attest the unsurpassed value of RM Y-STRs for male-relative differentiation purposes.

The 2011 GeFI collaborative exercise. Concordance study, proficiency testing and Italian population data on the new ENFSI/EDNAP loci D1S1656, D2S441, D10S1248, D12S391, D22S1045.

The 2011 collaborative exercise of the ISFG Italian Working Group GeFI was aimed at validating the five ENFSI/EDNAP miniSTR loci D1S1656, D2S441, D10S1248, D12S391 and D22S1045. The protocol required to type at least 50 multilocus profiles from locally resident individuals and two blind bloodstains in duplicate (i.e., using at least two different commercial kits), and to send the electropherograms to the Organizing Committee. Nineteen laboratories distributed across Italy participated, collecting a total of 960 samples. Full concordance was found for the five new miniSTRs as observed from the comparison of 13,150 alleles. The inspection of the electropherograms allowed the identification of a very limited number of mistypings in the miniSTR genotypes thus contributing to the establishment of an high quality Italian database of frequencies.

Application of alternative fixatives to formalin in diagnostic pathology.

Fixation is a critical step in the preparation of tissues for histopathology. The objective of this study was to investigate the effects of different fixatives vs formalin on proteins and DNA, and to evaluate alternative fixation for morphological diagnosis and nucleic acid preservation for molecular methods. Forty tissues were fixed for 24 h with six different fixatives: the gold standard fixative formalin, the historical fixatives Bouin and Hollande, and the alternative fixatives Greenfix, UPM and CyMol. Tissues were stained (Haematoxylin-Eosin, Periodic Acid Schiff, Trichromic, Alcian-blue, High Iron Diamine), and their antigenicity was determined by immunohistochemistry (performed with PAN-CK, CD31, Ki-67, S100, CD68, AML antibodies). DNA extraction, KRAS sequencing, FISH for CEP-17, and flow cytometry analysis of nuclear DNA content were applied. For cell morphology the alternative fixatives (Greenfix, UPM, CyMol) were equivalent to formalin. As expected, Hollande proved the best fixative for morphology. The morphology obtained with Bouin was comparable to that with formalin. Hollande was the best fixative for histochemistry. Bouin proved equivalent to formalin. The alternative fixatives were equivalent to formalin, although with greater variability in haematoxylin-eosin staining. It proved possible to obtain immunohistochemical staining largely equivalent to that following formalin-fixation with the following fixatives: Greenfix, Hollande, UPM and CyMol. The tissues fixed in Bouin did not provide results comparable to those obtained with formalin. The DNA extracted from samples fixed with alternative fixatives was found to be suitable for molecular analysis.