The way to medico legal identification was open at the end of the twenty‐first century by the “digital fingerprinting” represented by the multifactorial phenotypical trait, determined by both polygenic and environmental factors, followed by group‐specific antigens, or with specificity for blood and tissue, and ending with the DNA molecule in use today. Because of this aspect, the framework of modern forensic medicine includes a new field, that of forensic genetics, that mostly involves working with investigations that have human genotype identification as a goal.
Part of the book: Forensic Analysis
Since two and a half decades, in human identification, the short tandem repeat (STR) markers represent the “gold standard.” Besides them, haploid markers such as X-STR and Y-STR are also used to complement the autosomal markers. In human identification, DNA from body fluids, especially saliva, represents an important tool. The aim of this chapter is to present the importance of analyzing X-STR markers in a relatedness case between a sister and her presumptive brother, a carbonized victim using body fluids for their DNA identification. Our laboratory had to establish the relatedness between a woman and her presumptive brother (PB), who was the victim of a car accident explosion. In this case, as reference sample we used saliva collected on swabs from the woman and blood sample from the deceased victim. For the DNA extraction, DNA IQ Casework (Promega, USA) was used. DNA quantification was done with PowerQuant System kit (Promega, USA). Furthermore, the DNA samples were amplified with Investigator 24plex QS (Qiagen, Germany) for the STR markers and Investigator Argus 12-X QS kit (Qiagen, Germany) for the X-STR markers. The amplified DNA products were separated by capillary electrophoresis on a 3500 Genetic Analyzer. In this case, full genetic profiles were obtained for the woman and her presumptive brother on both STR and X-STR markers. Thus, we could confirm a full sibling relationship between them. Since the introduction of DNA in human identification, it represents a useful tool in establishing sibling relationship from different biological samples.
Part of the book: Saliva and Salivary Diagnostics
The first ever human identification through DNA analysis was done in the year 1987. Since then, this test has been used, not only in the ruling of civil and juridical cases, but also for human identification of missing persons and mass disaster victims. In this chapter we will present the usefulness of genetic DNA testing of skeletonized remains for human identification, by using automate DNA extraction from three different human bone types: tooth, femur and petrous pyramid. For each case, we obtained saliva samples on buccal swabs from relatives. After the bones were washed and cleaned, Bead Balls Mill Mix 20 (Tehtnica Domel, Slovenia), was used to obtain the bone powder. The DNA extraction from bone samples was performed on the automate Maxwell RSC 48 Instrument (Promega, USA), using the Maxwell FSC DNA IQ Casework Kit (Promega, USA). Power Quant System (Promega, USA) was used for DNA quantification of the samples. The DNA samples were amplified on a Pro Flex PCR System (Thermo Fischer, USA), using the Global Filer PCR Amplification Kit (Applied Biosystems, USA). PCR products were run on a 3500 Genetic Analyzer (Thermo Fischer, USA). Data analysis was performed by Gene Mapper 1.4. Considering that these cases involved DNA extraction from teeth, bones and old human remains, automate system was felt to be the best option to reduce handling errors and increase the possibilities of obtaining good quality DNA.
Part of the book: Criminology and Post-Mortem Studies