The personal identification of many samples recovered from under the sea

Long-term room temperature preservation of corpse soft tissue: an approach for tissue sample storage

Background

Disaster victim identification (DVI) represents one of the most difficult challenges in forensic sciences, and subsequent DNA typing is essential. Collected samples for DNA-based human identification are usually stored at low temperature to halt the degradation processes of human remains. We have developed a simple and reliable procedure for soft tissue storage and preservation for DNA extraction. It ensures high quality DNA suitable for PCR-based DNA typing after at least 1 year of room temperature storage.

Methods

Fragments of human psoas muscle were exposed to three different environmental conditions for diverse time periods at room temperature. Storage conditions included: (a) a preserving medium consisting of solid sodium chloride (salt), (b) no additional substances and (c) garden soil. DNA was extracted with proteinase K/SDS followed by organic solvent treatment and concentration by centrifugal filter devices. Quantification was carried out by real-time PCR using commercial kits. Short tandem repeat (STR) typing profiles were analysed with 'expert software'.

Results

DNA quantities recovered from samples stored in salt were similar up to the complete storage time and underscored the effectiveness of the preservation method. It was possible to reliably and accurately type different genetic systems including autosomal STRs and mitochondrial and Y-chromosome haplogroups. Autosomal STR typing quality was evaluated by expert software, denoting high quality profiles from DNA samples obtained from corpse tissue stored in salt for up to 365 days.

Conclusions

The procedure proposed herein is a cost efficient alternative for storage of human remains in challenging environmental areas, such as mass disaster locations, mass graves and exhumations. This technique should be considered as an additional method for sample storage when preservation of DNA integrity is required for PCR-based DNA typing.

Detectability of SGM Plus profiles in heart and lungs tissue samples incubated in different environments

The aim of the study was assessment of environmental effect on typeability of AmpFlSTR SGM Plus loci: D3S1358, VWA, D16S539, D2S1338, D81179, D21S11, D18S51, D19S433, TH01, FGA and gender marker amelogenin. Heart and lungs specimens collected during autopsies of five persons aged 20-30 years were incubated at 21 degrees C and 4 degrees C in different environmental conditions, fresh different water and soil conditions. DNA was extracted by organic method from tissue samples collected in 7-day intervals and subsequently typed using AmpFlSTR SGM Plus kit and ABI 310. Incubation at 21 degrees C and prevented air access, as well as in peat soil and in sand favoured faster DNA degradation reflected by decrease in typeability rate. In samples with negative genotyping results no DNA was found by fluorometric quantitation. Decomposed soft tissues are potential material for DNA typing.

Typeability of AmpFlSTR SGM Plus Loci in Brain and Thyroid Gland Tissue Samples Incubated in Different Environments

Autolysis and putrefaction are crucial factors responsible for degradation of cells, tissues, and organs. Postmortem changes may assume different course depending on extrinsic and intrinsic conditions. The aim of the study was assessment of environmental effect on typeability of AmpFlSTR SGM Plus loci: D3S1358, VWA, D16S539, D2S1338, D81179, D21S11, D18S51, D19S433, TH01, FGA, and gender marker amelogenin. Brain and thyroid gland tissue specimens collected during autopsies of five persons aged 20-30 years were incubated at 21 degrees C and 4 degrees C in different environmental conditions. DNA was extracted by organic method from tissue samples collected in 7-day intervals and subsequently typed using AmpFlSTR SGM Plus kit and ABI 310. A fast decrease in typeability rate was seen in specimens incubated in peat soil and in sand. Brain tissue samples were typeable in all AmpFlSTR SGM Plus loci within 126 days of incubation at 4 degrees C. Faster DNA degradation was recorded in thyroid gland specimens. In samples with negative genotyping results, no DNA was found by fluorometric quantitiation.

The identification of a victim using the DGGE method for trace deposits collected on adhesive film

The denaturant gradient gel electrophoresis (DGGE) method was used in order to simultaneously estimate the genotypes of different factors in a gel plate consisting of one sheet. A genotype analysis of the blood groups (MN, Duffy, Kidd type) and serotype (Gc system) was carried out. DNA samples were extracted from trace deposits which were transferred on adhesive film from a blood trace obtained from a car tire after a fatal car accident. The reference DNA was prepared from the victim's blood. The PCR amplification fragments were amplified from the gene which controlled each blood group. The primers were designed in order to analyze the genotypes with one to three base substitutions in the amplification product. The denaturant concentration limit of the gel for the DGGE method to detect each genotype of the blood groups (MN, Duffy, Kidd type and Gc system) and other conditions of electrophoresis were performed according to previously methods. The each genotype of the blood groups and the Gc system were all simultaneously distinguished in one plate.