Federica Alessandrini

Y-chromosome genetic structure in sub-Apennine populations of Central Italy by SNP and STR analysis

To define the Y-chromosome genetic structure in Apennine populations, 17 Y-chromosome short tandem repeats (Y-STRs) and 37 Y-single nucleotide polymorphisms (Y-SNPs) were typed in 162 subjects living in the upland area of the Marches (Central Italy). A total number of 155 haplotypes (haplotype diversity was 0.9994) and 14 SNP haplogroups were observed. Testing high-resolution Y-chromosome data sets, e.g. using Yfiler and SNPs, increases the discriminatory capacity in individual identification for forensic purposes. It is also useful in autochthonous population and micro-population studies to highlight the most informative loci for evolutionary aims.

DNA degradation and genetic analysis of empty puparia: genetic identification limits in forensic entomology.

Puparial cases are common remnants of necrophagous flies in crime investigations. They usually represent the longest developmental time and, therefore, they can be very useful for the estimation of the post-mortem interval (PMI). However, before any PMI estimate, it is crucial to identify the species of fly eclosed from each puparium associated with the corpse. Morphological characteristics of the puparium are often distinctive enough to permit a species identification. But, even an accurate morphological analysis of empty puparia cannot discriminate among different species of closely related flies. Furthermore, morphological identification may be impossible if the fly puparia are poorly preserved or in fragments. This study explores the applicability of biomolecular techniques on empty puparia and their fragments for identification purposes. A total of 63 empty puparia of necrophagous Diptera resulting from forensic casework were examined. Samples were divided into three groups according to size, type and time of eclosion in order to verify whether the physical characteristics and puparia weathering can influence the amount of DNA extraction. The results suggest that a reliable genetic identification of forensically important flies may also be performed from empty puparia and/or their fragments. However, DNA degradation can deeply compromise the genetic analysis since the older the fly puparia, the smaller are the amplified fragments.

Multiplex PCR Development of Y-chromosomal Biallelic Polymorphisms for Forensic Application

Single-nucleotide polymorphisms of Y chromosome (Y-SNPs) are a class of markers of interest in forensic investigations, because many of them show regional specificity, providing useful information about the geographic origin of a subject or evidence under investigation. A first multiplex with 7 SNPs (M35, M89, M9, M170, M172, M45, M173), which occur in the basal branches of the phylogenetic tree and are able to assign a subject to known most frequent European haplogroups, was designed. SNP genotyping was accomplished by hot-start PCR with primers amplifying fragments between 96 and 136 nucleotides, minisequencing, and capillary electrophoresis of extension products. Ninety seven subjects of known geographic provenance were studied, of which 68 from Europe. Of these, 57 had mutations found more frequently in European haplogroups and 11 more frequent in Asian populations. Subjects from non-European countries were also examined and had haplogroups common in their regions of provenance. Experiments with low molecular weight DNA gave positive amplification from 1 ng of DNA for all seven SNPs.

Forensic interlaboratory evaluation of the ForFLUID kit for vaginal fluids identification

Identification of vaginal fluids is an important step in the process of sexual assaults confirmation. Advances in both microbiology and molecular biology defined technical approaches allowing the discrimination of body fluids. These protocols are based on the identification of specific bacterial communities by microfloraDNA (mfDNA) amplification. A multiplex real time-PCR assay (ForFLUID kit) has been developed for identifying biological fluids and for discrimination among vaginal, oral and fecal samples. In order to test its efficacy and reliability of the assay in the identification of vaginal fluids, an interlaboratory evaluation has been performed on homogeneous vaginal swabs. All the involved laboratories were able to correctly recognize all the vaginal swabs, and no false positives were identified when the assay was applied on non-vaginal samples. The assay represents an useful molecular tool that can be easily adopted by forensic geneticists involved in vaginal fluid identification.

Identification and functional analysis of a new putative caveolin-3 variant found in a patient with sudden unexplained death

BackgroundSudden cardiac death (SCD) is the clinical outcome of a lethal arrhythmia that can develop on the background of unrecognized channelopathies or cardiomyopathies. Several susceptibility genes have been identified for the congenital forms of these cardiac diseases, including caveolin-3 (Cav-3) gene. In the heart Cav-3 is the main component of caveolae, plasma membrane domains that regulate multiple cellular processes highly relevant for cardiac excitability, such as trafficking, calcium homeostasis, signal transduction and cellular response to injury. Here we characterized a new putative Cav-3 variant, Cav-3 V82I, found in a patient with SCD.ResultsIn heterologous systems Cav-3 V82I was expressed at significantly higher level than Cav-3 WT and accumulated within the cells. Cells expressing Cav-3 V82I exhibited a decreased activation of extracellular-signal-regulated kinases (ERKs) and were more vulnerable to sub-lethal osmotic stress.ConclusionConsidering that abnormal loss of myocytes can play a mechanistic role in lethal cardiac diseases, we suggest that the detrimental effect of Cav-3 V82I variant on cell viability may participate in determining the susceptibility to cardiac death.

Unusual association of three rare alleles and a mismatch in a case of paternity testing.

This study reports a paternity case analyzed by the AmpFlSTR Identifiler Kit (AB) in which father and daughter shared three rare alleles for D19S433, D18S51 and TH01 microsatellites. The case also showed an apparent exclusion, due to a mutation at the D3S 1358 microsatellite. Sequencing analysis was performed to assess the size of the rare alleles and to establish their structure, which revealed some molecular variations in regions flanking the motif repeats.

Investigation on genetic thrombophilic factors in FFPE autopsy tissue from subjects who died from pulmonary embolism

Venous thromboembolism (VTE) is a multifactorial disease determined by a combination of inherited and acquired factors. Inherited factors include mutations in the genes coding for coagulation factors, some of which seem to exert a differential influence on the risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE). In post-mortem studies of subjects who have died from pulmonary embolism (PE), the analysis of the factors that may have augmented the VTE risk is often limited to acquired factors. This is due to the complexity—and sometimes the unfeasibility—of analyzing genetic factors and to insufficient knowledge of their individual roles in PE development. The present study used formalin-fixed paraffin-embedded (FFPE) tissue to investigate a panel of 12 polymorphisms—the largest ever studied—that affect the VTE risk. Tissue samples came from post-mortem examinations performed by the specialists of the Section of Legal Medicine of the Department of Pathology of Marche’s Polytechnic University, and by the specialists of Health Care District Hospital of Imola, on 44 subjects who died from PE in the period 1997–2014. All individuals were found to have at least one mutation affecting the VTE risk. The present study demonstrates that genetic analysis can be performed post-mortem and the results are useful for forensic investigations, especially from MTHFR C677T and PAI-1 4G/5G polymorphisms. Broader studies using the techniques described herein are needed to determine the relative influence of the individual polymorphisms and their interaction in PE deaths.

Environmental microbiology: perspectives for legal and occupational medicine

The analysis of microorganism population is crucial in several medical fields. This is especially true in legal and occupational medicine, where the specialist can be asked to perform an evaluation of several environmental matrices. In these two medical fields an accurate microbiological analysis is part of a wide process aimed to the definition of the interactions between human beings and environment. In legal medicine it is important to deserve attention to the identification of microbiological traces in order to better understand past events, while in occupational and preventive medicine the microbiological evaluation of environmental samples is crucial for an effective risk management and the definition of safety procedures. The achievement of these objectives requires the comprehension of microbial biodiversity and not only the identification of few biomarkers. In the present paper, the complexity of this process is highlighted through the presentation of typical scenarios where microorganism population analyses are relevant in legal medicine and occupational medicine. The similarities between the microbiological approach in legal and occupational medicine lead to the sharing of laboratory approaches. A description of technological evolution shows how new protocols and procedures are supporting a wider microbiological comprehension of specimens. The development of molecular tools has opened new opportunities, but it has underlined the need for the implementation of new standardized procedures dedicated to these medical fields, where science and medicine interact with the law. In addition, the rapid evolution of massive parallel sequencing technologies requires the implementation of new bioinformatic tools with a user-friendly interface.

Multiplex PCR development of Y-chromosomal biallelic polymorphisms for forensic applications

Abstract The aim of this study is to set-up multiplex PCR of NRY single nucleotide polymorphisms (SNPs) suitable for forensic purposes. A first multiplex has been developed with SNP loci defining the European haplogroups (M35, M89, M172, M170, M9, M173, M45). PCR was performed with primers designed to produce amplicons in a range between 96 and 136 bp starting from 1 ng of DNA template. PCR product was minisequenced with tailed primers of different length and run in an automated five-colour capillary electrophoresis sequencer.