The strategies to DVI challenges in Typhoon Morakot

Dead migrants in the Mediterranean: genetic analysis of bone samples exposed to seawater

In April 2015, a fishing boat that departed from Libya with about 1,000 migrants on board sank in the Mediterranean Sea. Most of the migrants were packed in the hull of the boat and drowned in the shipwreck. After fifteen months, the ship was recovered from the seabed and brought to a Sicilian naval area for forensic investigations. Skeletal remains belonging to more than 700 people were retrieved. A selected sample composed of 80 victims was considered in order to evaluate the possibility of achieving genetic profiles useful for a positive identification from these challenging specimens. The molecular features of the DNA recovered from a significant number of real casework samples exposed to seawater for long periods of time were described for the first time. Three different DNA extraction protocols and three different commercial kits were employed in order to generate genetic profiles based on the characterization of 21 autosomal STR loci. The combination of multiple DNA extractions and the cross-checking of multiple PCR amplifications with different kits allowed to obtain reliable genetic profiles characterized by at least 16 STR markers in more than 70% of the samples. The factors that could have affected the different quality of the genetic profiles were investigated and the bone preservation was examined through microscopic and macroscopic analyses. The approach presented in this study could be useful in the management of the genetic analysis of bone samples collected in other similar DVI scenarios. The genetic profiles recovered from the bone samples will be compared in kinship analysis to putative relatives of the victims collected in Africa in order to obtain positive identifications.

Challenges in implementing best practice DVI guidelines in low resource settings: lessons learnt from the Meethotamulla garbage dump mass disaster

The management of mass fatalities following disasters is a complex process which requires the involvement of multiple stakeholders and resources. A garbage dump at Meethotamulla in Sri Lanka suddenly collapsed, resulting in the death of 32 individuals. Efforts to implement best practice guidelines in Disaster Victim Identification (DVI) during this disaster revealed several important aspects that need to be considered by the forensic community. Delays in initiating the legal processes to investigate and manage the incident resulted in public dissatisfaction towards the post-disaster management process. Body recovery by Police and military personnel without the involvement of medical teams had numerous shortcomings including the lack of proper tagging and photography, commingling of body parts, and non-preservation of personal items. Public expectation and demand for early release of the bodies conflicted with the necessity to undergo a stringent DVI process according to best practice guidelines. Many adaptations and alternate strategies were necessary to ensure that DVI could be done scientifically. The use of primary identification markers including odontology and DNA had many limitations including non-availability of antemortem data, resource availability and cost. Identification was established using a combination of secondary identification markers including clothing, jewelry, scars, tattoos, morphological descriptions and circumstantial evidence. In two cases, odontological features further supported positive identification. Samples for DNA were obtained and preserved but were not utilized in establishing the identities. This paper highlights the need for better public awareness and multidisciplinary commitment in managing mass fatalities and also reflects on the challenges of implementing best practice DVI guidelines in low-resource settings with different legal and socio-cultural expectations.

A novel strategy for sibship determination in trio sibling model

Aim

To use a virtually simulated population, generated from published allele frequencies based on 15 short tandem repeats (STR), to evaluate the efficacy of trio sibship testing and sibling assignment for forensic purposes.

Methods

Virtual populations were generated using 15 STR loci to create a large number of related and unrelated genotypes (10 000 trio combinations). Using these virtual populations, the probability of related and unrelated profiles can be compared to determine the chance of inclusions of being siblings if they are true siblings and the chance of inclusion if they are unrelated. Two specific relationships were tested – two reference siblings were compared to a third true sibling (3S trio, sibling trio) and two reference siblings were compared to an unrelated individual (2S1U trio, non-sibling trio).

Results

When the likelihood ratio was greater than 1, 99.87% of siblings in the 3S trio population were considered as siblings (sensitivity); 99.88% of non-siblings in the 2S1U trio population were considered as non-siblings (specificity); 99.9% of both populations were identified correctly as siblings and non-siblings; and the accuracy of the test was 99.88%.

Conclusions

The high sensitivity and specificity figures when using two known siblings compared to a putative sibling are significantly greater than when using only one known relative. The data also support the use of increasing number of loci allowing for greater confidence in genetic identification. The system established in this study could be used as the model for evaluating and simulating the cases with multiple relatives.

DNA analysis in Disaster Victim Identification

DNA profiling and matching is one of the primary methods to identify missing persons in a disaster, as defined by the Interpol Disaster Victim Identification Guide. The process to identify a victim by DNA includes: the collection of the best possible ante-mortem (AM) samples, the choice of post-mortem (PM) samples, DNA-analysis, matching and statistical weighting of the genetic relationship or match. Each disaster has its own scenario, and each scenario defines its own methods for identification of the deceased.