Highly efficient and automated extraction of DNA from human remains using a modified EZ1 protocol

Assessment of the efficiency of DNA isolation and profiling applying a temperature-driven method in human remains

The identification of human remains is of utmost importance in a variety of scenarios. One of the primary identification methods is DNA. DNA extraction from human remains could be difficult, particularly in situations where the remains have been exposed to environmental conditions and other insults. Several studies tried to improve extraction by applying different approaches. ForensicGEM Universal (MicroGem) is a single-tube approach to DNA extraction and a temperature-driven method that could have some advantages with respect to previous techniques, among them, reducing the risk of contamination, not requiring specialized equipment, or several steps to perform. The aim of this study was to assess, for the first time, the efficiency of DNA extraction and quality of STR profiles applying the MicroGem protocol and modifications of this protocol from tooth samples in comparison with automatic extraction (AE). Our results indicated that AE and MicroGem performed similar, though with variability depending on the MicroGem modifications, increasing the DNA yield and STR profile quality when DNA is concentrated with Microcon. These findings demonstrated the efficiency of this methodology for DNA extraction from human remains while also providing a simple and quick technique suitable to apply in a variety of forensic scenarios.

Comparative study of Rapid DNA versus conventional methods on compromised bones

Equivalent amounts of compromised bones were used to directly compare STR success of conventional and Rapid DNA methods. Conventional DNA extraction methods, including manual full demineralization and semi-automated PrepFiler BTA/ AutoMate Express (ThermoFisher Scientific), provided insights regarding the DNA quantity and extent of degradation of each compromised bone analyzed with ANDE 6C (ANDE Corp) and RapidHIT ID (ThermoFisher Scientific) Rapid systems. Full demineralization provided higher DNA yields than extraction with the AutoMate Express for quality control (QC) and environmentally challenged bones. The degradation indices ranged from ∼1.8 to 73. Both demineralization and AutoMate Express extracts benefited from additional clean-up with NucleoSpin XS devices, which usually resulted in more alleles being detected than without further clean-up. Complete "CODIS 20″ profiles could be obtained with bone QC1 with all methods. However, among the 14 compromised bones with low DNA content, complete CODIS 20 profiles were detected for 7, 4, and 0 bones analyzed with demineralization, AutoMate Express and ANDE methods, respectively. The RapidHIT ID was the least sensitive method, providing the fewest detectable alleles for the bones tested. Whereas extracted DNA of approximately 0.1 ng can yield complete GlobalFiler STR profiles, at least 30 ng was required for complete FlexPlex 27 profiles using the ANDE 6C Rapid DNA system. In addition to being less sensitive than conventional methods, the tested Rapid DNA approaches were less predictable when attempting to improve STR success and proved to be less reliable in genotyping accuracy.

An analysis of data curated from 5 years of identifying human remains

An archive of 5 years of cases involving the identification of human remains was curated, collecting information on: The sample type submitted, the number of STR loci yielding interpretable results, the kinship challenge posed, and the outcome for the case. A total of 129 cases of remains ID were investigated using manual DNA extraction and recovery methods with amplification of STR markers using the Power Plex 21 multiplex STR kit from Promega Corp. In 52 cases, blood spots collected by the ME were provided as sample and in 100% of those cases, probabilities of relatedness to the reference samples was ≥99%. In 77 cases, tissue other than blood was provided as a source of DNA. These other samples were grouped categorically into long bones (femur and tibia; 40 cases), skull bones/teeth (11 cases), other bones (16 cases), and tissue (normally adherent to bone) (10 cases). Reference samples provided for cases included alleged parents or child(ren) of the victim (86 cases), alleged full siblings of the victim (38 cases), or alleged second-order relatives (five cases). The overall success rate in confirming the identity of the source of the remains in these cases was 89.2%. Our results demonstrate that a laboratory can be often successful identifying human remains using methods easily implemented in any DNA typing laboratory.

DNA and protein analyses of hair in forensic genetics

Hair is one of the most common pieces of biological evidence found at a crime scene and plays an essential role in forensic investigation. Hairs, especially non-follicular hairs, are usually found at various crime scenes, either by natural shedding or by forcible shedding. However, the genetic material in hairs is usually highly degraded, which makes forensic analysis difficult. As a result, the value of hair has not been fully exploited in forensic investigations and trials. In recent years, with advances in molecular biology, forensic analysis of hair has achieved remarkable strides and provided crucial clues in numerous cases. This article reviews recent developments in DNA and protein analysis of hair and attempts to provide a comprehensive solution to improve forensic hair analysis.