Vitreous humour as a potential DNA source for postmortem human identification.

PURPOSEThe aim of this study was the assessment of vitreous humor as a potential DNA for forensic human postmortem identification.MATERIAL AND METHODSVitreous humor samples were collected using two alternative approaches from 25 corpses of either sex during autopsies. DNA was extracted by standard organic method. Recovered DNA was quantitiated fluorometrically. AmpFlSTR SGM Plus kit and ABI 310 Genetic Analyzer (Applera) were used to obtain genetic profiles.RESULTSDifferent DNA yields were quantitated in vitreous body depending on cause of death and sampling approach.CONCLUSIONVitreous humor is a potential DNA for forensic human postmortem identification depending on a sampling method used

Development of the VISAGE enhanced tool and statistical models for epigenetic age estimation in blood, buccal cells and bones

DNA methylation is known as a biomarker for age with applications in forensics. Here we describe the VISAGE (VISible Attributes through GEnomics) Consortium’s enhanced tool for epigenetic age estimation in somatic tissues. The tool is based on eight DNA methylation markers (44 CpGs), bisulfite multiplex PCR followed by sequencing on the MiSeq FGx platform, and three statistical prediction models for blood, buccal cells and bones. The model for blood is based on six CpGs from ELOVL2, MIR29B2CHG, KLF14, FHL2, TRIM59 and PDE4C, and predicts age with a mean absolute error (MAE) of 3.2 years, while the model for buccal cells includes five CpGs from PDE4C, MIR29B2CHG, ELOVL2, KLF14 and EDARADD and predicts age with MAE of 3.7 years, and the model for bones has six CpGs from ELOVL2, KLF14, PDE4C and ASPA and predicts age with MAE of 3.4 years. The VISAGE enhanced tool for age estimation in somatic tissues enables reliable collection of DNA methylation data from small amounts of DNA using a sensitive multiplex MPS assay that provides accurate estimation of age in blood, buccal swabs, and bones using the statistical model tailored to each tissue

A Machine-Learning-Based Approach to Prediction of Biogeographic Ancestry within Europe

Data obtained with the use of massive parallel sequencing (MPS) can be valuable in population genetics studies. In particular, such data harbor the potential for distinguishing samples from different populations, especially from those coming from adjacent populations of common origin. Machine learning (ML) techniques seem to be especially well suited for analyzing large datasets obtained using MPS. The Slavic populations constitute about a third of the population of Europe and inhabit a large area of the continent, while being relatively closely related in population genetics terms. In this proof-of-concept study, various ML techniques were used to classify DNA samples from Slavic and non-Slavic individuals. The primary objective of this study was to empirically evaluate the feasibility of discerning the genetic provenance of individuals of Slavic descent who exhibit genetic similarity, with the overarching goal of categorizing DNA specimens derived from diverse Slavic population representatives. Raw sequencing data were pre-processed, to obtain a 1200 character-long binary vector. A total of three classifiers were used—Random Forest, Support Vector Machine (SVM), and XGBoost. The most-promising results were obtained using SVM with a linear kernel, with 99.9% accuracy and F1-scores of 0.9846–1.000 for all classes

Examination of nuclear DNA in bone material - selected cases

Kości niejednokrotnie stanowią jedyne źródło materiału biologicznego pozwalającego na typowanie DNA w przypadku spraw archiwalnych, identyfikacji zaginionych osób, czy też identyfikacji ofiar katastrof. Wynika to z unikalnych cech budowy kości, stanowiących swoistą barierę fizyczną i chemiczną dla czynników powodujących degradację. W artykule przedstawiono kilka przypadków, w których jedynym dostępnym materiałem badawczym był materiał kostny. Dzięki zastosowaniu metodyki badań kości, stosowanej w Centralnym Laboratorium Kryminalistycznym Policji, możliwym było uzyskanie pozytywnych wyników badań. Spośród 13 badanych próbek, dla różnego rodzaju kości, we wszystkich przypadkach uzyskano pełne profile DNA. Jedynie w przypadku badań kości potylicznej otrzymano niepełny profil DNA. Badane kości różniły się budową w zależności jaki stanowiły element szkieletu. W prezentowanych sprawach różny był także wpływ czynników zewnętrznych mających znaczenie w przypadku degradacji DNA.It happens quite often that bones constitute the only source of biological material allowing for DNA profiling in old cases, identification of missing individuals or unknown remains. This is due to a bone structure providing unique physical and chemical barrier for degrading factors. The aim of this article was to describe cases where the only biological material for examination involved bone samples. Methods routinely used for bone and teeth examination by experts from the Central Forensic Laboratory of the Police allowed for obtaining positive results. Out of 13 examination samples (bones), in all cases full DNA profiles were obtained. The exception was the examination of occipital bone which resulted in partial profile. Examined bones differed in terms of structure depending on which part of skeleton they originated from. In the discussed cases, the impact of external factors contributing to degradation of DNA also varied