Revista de investigación forense

The Y chromosome contains the largest non-recombining portion in the human genome. Y-Binary polymorphisms, also known as a single nucleotide polymorphisms (SNPs), are a series of biallelic polymorphisms occurring on the non-recombining region of the Y chromosome (NRY), which represent a precious tool for human evolutionary studies and, potentially, for forensic applications. Low mutation rate, paternal inheritance, and absence of recombination make Y-SNPs particularly suitable for the identification of stable paternal lineages and the reconstruction of an ancestral state from which to explore the evolution of humans. Also, these markers would allow inference of the paternal ancestry of unknown samples which could be useful in forensic applications. In the present study we analyzed 22 biallelic Y-SNPs in 159 males belonging to three ethnic groups (Arab n = 42, Berber n = 67 and Sahrawi n = 50) from Morocco. A total of 10 different haplogroups were identified in this sample representative of Moroccan population. The most common Y chromosome haplogroups is E1b1b1, E1b1b1b and J1 with frequencies of 56%, 49% and 10% respectively.

We present a method for detecting new malicious executables, which comprise the following steps: (a) in an offline training phase, finding a set of system call sequences that are characteristic only to malicious files, when such malicious files are executed, and storing said sequences in a database; (b) in a real time detection phase, for each running executable, continuously monitoring its issued system calls and comparing with the stored sequences of system calls within the database to determine whether there exists a match between a portion of the sequence of the run-time system calls and one or more of the database sequences, and when such a match is found, declaring said executable as malicious. We have evaluated our method and the preliminary results are promising and justify the use of system calls sequences for the purpose of detection of new malicious executables

Nowadays, the use of molecular biology in forensics has made it possible to identify human victim and sometimes even the circumstances under which the death occurred through. In our case, a corpse of a 50-years old man with a gunshot wound was found in the woods. The suspected murderer declared that it had been a hunting accident while he shot a wild boar. During the autopsy, a bullet (Borra-bullet Gualandi, 32 gr) was found in the abdomen of the victim. The authors investigated the presence of boar and victim blood both on the bullet, in order to substantiate the thesis of the hunting accident. Laboratory investigations underscored the presence of human cellular material on the bullet, which corresponds to profile of the victim and human and porcine ribosomal DNA. Through this investigation, the authors showed that it was a hunting accident, because the bullet passed through the body of the boar before hitting the victim.

Development times and survivorship of Lucilia sericata (Meigen, 1826) were measured for different constant temperatures. In addition, lower threshold (tL) and thermal constant (Kt) were estimated for a local population. The estimated development time calculated from mean or minimum development time induces a bias that may be reduced using a model of intrinsic variability. In order to quantify variation in emergence rate during the development time, a simulation method was developed by adapting the Régnière’s method. The adapted model allowed accurate prediction of the emergence profile of L. sericata at constant temperature in the linear portion of the development curve. We believe that the application of this method in forensic entomology cases could increase the reliability of the conclusions of an entomological Post Mortem Interval (PMI) estimation.

AIDS, acronym of Acquired Immune Deficiency Syndrome, is a clinical picture related to Human Immunodeficiency Virus (HIV) infection. In the last 20 years this infection has had a high and progressive diffusion. Generally, the HIV antibody tests (ELISA plus RIBA methods) are used to revealed the infection. In this paper, the Authors present the HIV testing in Italian legislation and the comparison with some international laws, particularly for the minors. In most European and American Countries this test is volunteer and for minors is not require the consent of parents; in Italy the implementation of the test is today governed by the law 135/1990. This law establishes that the conduct test is volunteer and the informed consent is obligatory; but nothing is said about the consent of the child. The actual Italian law about the minor consent for us is unsatisfactory. The international experience can be useful to change or supplement the current Italian act.

With the flood of whole genome finished and draft microbial sequences, analysts need faster, more scalable bioinformatics tools for sequence comparison. An algorithm is described to find single nucleotide polymorphisms (SNPs) in whole genome data. It scales to hundreds of bacterial or viral genomes, and can be used for finished and/ or draft genomes available as unassembled contigs. The method is fast to compute, finding SNPs and building a SNP phylogeny in seconds to hours. It identified thousands of putative SNPs from all publicly available Filoviridae, Poxviridae, foot-and-mouth disease virus, Bacillus, and Escherichia coli genomes and plasmids. The SNP-based trees it generated were consistent with known taxonomy and trees determined in other studies. The approach described can handle as input hundreds of megabases of sequence in a single run. The algorithm kSNP is based on k-mer analysis using suffix arrays and requires no multiple sequence alignment.

Chromatographic analysis by the HPLC technique with Diode Array Detector was employed for MDMA determination. A mobile phase of methanol/water (90:10v/v) allowed a peak signal for MDMA in 16 minutes. Optimized spectrophotometric signal was obtained at a wavelength of 240 nm. The analytical curve from 5.0 to 100.0ppm of MDMA was obtained, showing a linear correlation coefficient of 0.9997 and a detection limit of 2.94ppm. This methodology was employed at the dosage of confiscated samples of ecstasy in the Scientific Police Laboratory of Ribeirão Preto-SP city.

A population sample of 163 unrelated individuals from the Mexican state of Jalisco (West of Mexico) was PCRtyped with the Geneprint® STR System including nine autosomal STRs (CSF1PO, TPOX, TH01, F13A01, FESFPS, vWA, D16S539, D7S820 and D13S317). For this purpose, we implemented an alternative protocol for STR silver stain detection, which provides some economical and technical benefits: 1) make easy the gel handling; 2) simplify the process avoiding the use of some –toxic– reagents; 3) require lesser timer and made-in-home solutions; 4) the original gels can be dried and stored for re-analysis, if necessary. The allele frequencies estimated were similar to a previous report from the same Mexican population, which allowed pooling STR genotype data for upgrade the forensic parameter estimates (n= 472). However, this is the first –and unique– population study in Mexico for F13A01 and FESFPS; thus, the sample size did not increased for these loci (n= 163). In the studied population, genotype distribution by locus and two-loci combination was in agreement with Hardy-Weinberg expectations for all nine STRs. For the STR system, the power of discrimination (PD) and exclusion (PE) were >99.999% and 99.9%, respectively.

In the forensic sciences, DNA analysis is especially useful in sexual assault cases where body contact is made or bodily fluids are exchanged. However, its usefulness can be severely limited within the contour of the criminal justice system. This article discusses a case wherein short tandem repeat DNA typing was used to charge the defendant with sexual assault of a child. The State’s DNA technicians analyzed the victim’s underclothing and reviewed the victim’s sexual assault nurse examination (SANE). Our independent review of the State’s forensic laboratory work showed that the samples used to obtain a DNA match from the victim’s underclothing and the defendant revealed a third contributor. An allele was found that did not match either the victim or the defendant as shown by us as expert witness. A ruling by the trial judge limited what the jury was allowed to hear regarding our findings. The defendant was found guilty. The defendant appealed the guilty verdict based on the trial judge’s decision to limit defense expert witness testimony. Following established law, the appellate court upheld the conviction, ruling that a victim’s testimony alone, with or without any corroborating forensic evidence, supports a finding of guilt.