Delta9-THC determination by the EU official method: evaluation of measurement uncertainty and compliance assessment of hemp samples.

Hemp cultivation is living a period of renewed interest worldwide after long years of opposition and abandonment. The European Union (EU) allows and subsidizes the growing of fiber and oilseed cultivars of Cannabis sativa L. with respect to the THC content limit of 0.2%. The EU method for the quantitative determination of Δ9-tetrahydrocannabinol (THC) content in hemp varieties provides to apply a tolerance of 0.03 g of THC per 100 g of sample concerning compliance assessment to that limit. However, the method does not report any precision data, especially useful as a function of THC content to evaluate measurement uncertainty and therefore to establish the conformity of hemp at different THC legal limits. Measurement uncertainty of the method by both bottom-up and top-down approach, besides repeatability and reproducibility, was investigated and estimated in the THC concentration range 0.2-1.0%, which includes the different legal limits set out for hemp around the world. We proposed Decision Rules for conformity of hemp showing that a non-compliant declaration beyond reasonable doubt should be stated when the THC content, as a mean result on a duplicate analysis, exceeds the limit by at least 11-15%, depending on THC limit. We highlighted other issues concerning practical aspects of hemp analysis, from sampling to evaluation of results, as well as the need to carry out collaborative studies on the EU method.

The Yara Gambirasio case: Combining evidence in a complex DNA mixture case.

Here, we illustrate how statistical methods can help extract information from mixed DNA profiles pertaining to an Italian case, referred to by the media as The murder of Yara Gambirasio. We base the analysis on a model for DNA mixtures that takes fully into account the peak heights and possible artefacts, like stutter and dropout that might occur in the DNA amplification process. We show how to combine the evidence from multiple samples and from different marker systems all within the model framework. The combined evidence is used for deconvolution, where the focus is to find likely profiles for the donors to the sample. We also show how a mixture can be used to establish familial relationships between a reference profile and a donor to the mixed DNA sample. We compare results based on a single mixed DNA profile, combination of replicates, combinations of different samples and combinations of different kits. Based on the Yara case, we discuss just a few of the plethora of possibilities of combining evidential information.

Pet fur or fake fur? A forensic approach.

BACKGROUND: In forensic science there are many types of crime that involve animals. Therefore, the identification of the species has become an essential investigative tool. The exhibits obtained from such offences are very often a challenge for forensic experts. Indeed, most biological materials are traces, hair or tanned fur. With hair samples, a common forensic approach should proceed from morphological and structural microscopic examination to DNA analysis. However, the microscopy of hair requires a lot of experience and a suitable comparative database to be able to recognize with a high degree of accuracy that a sample comes from a particular species and then to determine whether it is a protected one. DNA analysis offers the best opportunity to answer the question, 'What species is this?' In our work, we analyzed different samples of fur coming from China used to make hats and collars. Initially, the samples were examined under a microscope, then the mitochondrial DNA was tested for species identification. For this purpose, the genetic markers used were the 12S and 16S ribosomal RNA, while the hypervariable segment I of the control region was analyzed afterwards, to determine whether samples belonged to the same individual. RESULTS: Microscopic examination showed that the fibres were of animal origin, although it was difficult to determine with a high degree of confidence which species they belonged to and if they came from a protected species. Therefore, DNA analysis was essential to try to clarify the species of these fur samples. CONCLUSIONS: Macroscopic and microscopic analysis confirmed the hypothesis regarding the analyzed hair belonging to real animals, although it failed to prove with any kind of certainty which actual family it came from, therefore, the species remains unknown. Sequence data analysis and comparisons with the samples available in GenBank showed that the hair, in most cases, belonged to the Canidae family, and in one case only to Felidae.

Allele frequencies of 15 autosomal STR loci in the Iraq population with comparisons to other populations from the middle-eastern region.

Allele frequencies for the 15 autosomal STR loci included in the AmpFlSTR((R)) IdentifilerTM PCR Amplification Kit panel from Applied Biosystems (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, TH01, TPOX, CSF1PO, D19S433, D2S1338, D16S539) and several statistical parameters were estimated from a sample of 103 unrelated individuals, mostly Shia and Sunni Arabs, living in most of central and southern Iraq provinces. We compared the allele frequency spectrum detected in the Iraqi population to allele frequencies from 11 other data sets from published studies of individuals from Turkey, Iraqi-Kurdistan, Saudi Arabia, Arab Emarates, Oman, Iran, Syria, and Jordan. Significant global differences in allele frequencies were detected in 9 of the 11 comparisons following sequential Bonferroni corrections. Comparisons with the two independent panels from Saudi Arabia were not significant after applying Bonferroni corrections, however, low P-values (P<0.05) associated with these two contrasts nonetheless suggested that at least slight genetic differences between populations may exist.

Y chromosome haplotypes in Central-South Italy: implication for reference database.

One hundred and fifty individuals have been sampled across Central-South Italy and genotyped for Y chromosome STRs by PowerPlex Y system. Comparison with previous Italian databases revealed that majority of Y chromosome variation still need to be sampled. Identification of locus duplications, distribution of genetic variation and firstly identified alleles point to the necessity of more focused sampling strategies for reference databases.

Forensic application of the luminol reaction as a presumptive test for latent blood detection.

The forensic application of the luminol chemiluminescence reaction is reviewed. Luminol has been effectively employed for more than 40 years for the presumptive detection of bloodstains which are hidden from the naked eye at crime scenes and, for this reason, has been considered one of the most important and well-known assays in the field of forensic sciences. This review provides an historical overview of the forensic use of luminol, and the current understanding of the reaction mechanism with particular reference to the catalysis by blood. Operational use of the luminol reaction, including issues with interferences and the effect of the luminol reaction on subsequent serological and DNA testing is also discussed.

Alpha-amylase kinetic test in bodily single and mixed stains.

Recently, in Italy, a murder and a putative sexual violence was accomplished on a child. A bodily fluids mixture on the child's underwear between the victim (female) and the suspect (male) was ascertained by short tandem repeat (STR) DNA typing and, due to the absence of seminal fluid, saliva from the suspect and urine from the child was hypothesized. In order to investigate the possibility of specifically and rapidly detecting saliva stains both alone and mixed with other bodily fluids, we used a quantitative spectrophotometric technique, named Amylase test, for the detection of alpha-amylases. We determined alpha-amylase activity and reaction kinetic curves in several samples collected from the child's underwear. In order to confirm our intuition, we first tested saliva, perspiration, and urine, singularly and in mixtures; second, several forensic stains including saliva, perspiration, urine stains, saliva/perspiration, and saliva/urine mixture stains were tested. Evaluating alpha-amylase activity values and time-course curves' behavior of alpha-amylase reactions we were able to recognize successfully, in all cases, the presence of saliva and to distinguish it specifically from other bodily fluids containing alpha-amylase. A further confirmation of our result was provided by STR DNA typing on several areas of the underwear: a clear correlation between alpha-amylases activity and male DNA was detected on all the samples evaluated.

Expression of seminal vesicle-specific antigen in serum of lung tumor patients.

Protein markers are commonly used in forensic medicine to establish the origin of human fluids detected in crime scenes. Semenogelins, the major protein constituents of semen coagulum, are the most effective markers for semen detection. Recently, it has been demonstrated that semenogelins are also ectopically expressed in small cell lung carcinomas (SCLC) and in a minority of non-small cell lung carcinomas (NSCLC). This finding prompted us to look for semenogelin expression in the serum of lung cancer patients. A set of 13 serum samples (3 from SCLC and 10 from NSCLC patients) was screened by enzyme-linked immunosorbent assay (ELISA), using a commercially available kit. Four of the NSCLC cases showed positive results. Ectopic expression of marker proteins in individuals affected by cancer could represent a potential source of forensic pitfalls.