Characterization of a modified amplification approach for improved STR recovery from severely degraded skeletal elements.

Degraded skeletal remains generally contain limited quantities of genetic material and thus DNA-based identification efforts often target the mitochondrial DNA (mtDNA) control region due to the relative abundance of intact mtDNA as compared to nuclear DNA. In many missing person cases, however, the discriminatory power of mtDNA is inadequate to permit identification when associated anthropological, odontological, or contextual evidence is also limited, and/or the event involves a large number of individuals. In situations such as these, more aggressive amplification protocols which can permit recovery of STR data are badly needed as they may represent the last hope for conclusive identification. We have previously demonstrated the potential of a modified Promega PowerPlex 16 amplification strategy for the recovery of autosomal STR data from severely degraded skeletal elements. Here, we further characterize the results obtained under these modified parameters on a variety of sample types including pristine control DNA and representative case work specimens. Not only is the amplification approach evaluated here sensitive to extremely low authentic DNA input quantities (6 pg), but when the method was applied to thirty-one challenging casework specimens, nine or more alleles were reproducibly recovered from 69% of the samples tested. Moreover, when we independently considered bone samples extracted with a protocol that includes complete demineralization of the bone matrix, the percentage of samples yielding nine or more reproducible alleles increased to 95% with the modified amplification parameters. Overall, direct comparisons between the modified amplification protocol and the standard amplification protocol demonstrated that allele recovery was significantly greater using the aggressive parameters, with only a minimal associated increase in artifactual data.

Capillary electrophoresis of human mtDNA control region sequences from highly degraded samples using short mtDNA amplicons.

The forensic applications of mtDNA sequencing center primarily on samples that are either highly degraded or contain little or no nuclear DNA, since the testing of these sample types is often unsuccessful with more widely used nuclear STR profiling assays. In these cases, sequence data from the noncoding mtDNA control region are targeted due to its high variability. However, the ease of authentic DNA recovery and the strategy used for recovery depend strictly on the quality of the sample. In this chapter, we will cover mitochondrial DNA sequencing procedures for short mtDNA amplicons which range in size from 100 to 350 bp. Generally speaking, amplicons of this size are required only for the most degraded specimens, and the protocols described here have been specifically developed for recalcitrant human skeletal remains encountered during the course of a large-scale missing persons' identification effort. DNA templates from these types of specimens tend to exhibit various forms of intrastrand damage that, in turn, manifest as artifacts in the sequence data. Because these artifacts are not generally observed among sequence data from pristine templates, we address the particular data idiosyncrasies that warrant additional scrutiny. Although this chapter will primarily highlight this particular application, the basic experimental parameters and data considerations should easily extend to other applications and/or sample types. The protocols described here have been deliberately designed to produce raw sequence electropherograms and final mtDNA profiles that adhere to the strictest forensic guidelines in terms of overall data quality.

Titanic's unknown child: the critical role of the mitochondrial DNA coding region in a re-identification effort.

This report describes a re-examination of the remains of a young male child recovered in the Northwest Atlantic following the loss of the Royal Mail Ship Titanic in 1912 and buried as an unknown in Halifax, Nova Scotia shortly thereafter. Following exhumation of the grave in 2001, mitochondrial DNA (mtDNA) hypervariable region 1 sequencing and odontological examination of the extremely limited skeletal remains resulted in the identification of the child as Eino Viljami Panula, a 13-month-old Finnish boy. This paper details recent and more extensive mitochondrial genome analyses that indicate the remains are instead most likely those of an English child, Sidney Leslie Goodwin. The case demonstrates the benefit of targeted mtDNA coding region typing in difficult forensic cases, and highlights the need for entire mtDNA sequence databases appropriate for forensic use.

Integrated DNA and fingerprint analyses in the identification of 60-year-old mummified human remains discovered in an Alaskan glacier.

This report describes the identification of a merchant mariner who perished in 1948 when Northwest Airlines Flight 4422, a DC-4 carrying 24 seamen and six crew members crashed into Mount Sanford, Alaska. Fifty-one years later, a human forearm and hand were found close by the wreckage of the plane, prompting identification efforts using DNA and fingerprints. There were significant challenges to both the fingerprint and DNA analyses. The hand was badly desiccated, making fingerprint friction-ridge detail almost invisible and the remains had been embalmed upon discovery, making DNA amplification difficult. We present the results of an interdisciplinary approach that successfully addressed these challenges and ultimately led to the identification of the remains. These efforts relied on efficient fingerprint rejuvenation and imaging techniques that improved print resolution, as well as new DNA extraction techniques optimized for aggressively embalmed remains.

Mystery solved: the identification of the two missing Romanov children using DNA analysis.

One of the greatest mysteries for most of the twentieth century was the fate of the Romanov family, the last Russian monarchy. Following the abdication of Tsar Nicholas II, he and his wife, Alexandra, and their five children were eventually exiled to the city of Yekaterinburg. The family, along with four loyal members of their staff, was held captive by members of the Ural Soviet. According to historical reports, in the early morning hours of July 17, 1918 the entire family along with four loyal members of their staff was executed by a firing squad. After a failed attempt to dispose of the remains in an abandoned mine shaft, the bodies were transported to an open field only a few kilometers from the mine shaft. Nine members of the group were buried in one mass grave while two of the children were buried in a separate grave. With the official discovery of the larger mass grave in 1991, and subsequent DNA testing to confirm the identities of the Tsar, the Tsarina, and three of their daughters--doubt persisted that these remains were in fact those of the Romanov family. In the summer of 2007, a group of amateur archeologists discovered a collection of remains from the second grave approximately 70 meters from the larger grave. We report forensic DNA testing on the remains discovered in 2007 using mitochondrial DNA (mtDNA), autosomal STR, and Y-STR testing. Combined with additional DNA testing of material from the 1991 grave, we have virtually irrefutable evidence that the two individuals recovered from the 2007 grave are the two missing children of the Romanov family: the Tsarevich Alexei and one of his sisters.

High efficiency DNA extraction from bone by total demineralization.

In historical cases, missing persons' identification, mass disasters, and ancient DNA investigations, bone and teeth samples are often the only, and almost always the best, biological material available for DNA typing. This is because of the physical and chemical barrier that the protein:mineral matrix of bone poses to environmental deterioration and biological attack. Most bone extraction protocols utilized in the forensic community involve an incubation period of bone powder in extraction buffer for proteinase digestion, followed by the collection of the supernatant, and the disposal of large quantities of undissolved bone powder. Here we present an extremely efficient protocol for recovery of DNA by complete demineralization, resulting in full physical dissolution of the bone sample. This is performed in a manner that retains and concentrates all the reagent volume, for complete DNA recovery. For our study, we selected 14 challenging bone samples. The bones were extracted side-by-side with our new demineralization protocol and the standard extraction protocol in use at AFDIL. A real-time quantification assay based on the amplification of a 143 bp mtDNA fragment showed that this new demineralization protocol significantly enhances the quantity of DNA that can be extracted and amplified from degraded skeletal remains. We have used this technique to successfully recover authentic DNA sequences from extremely challenging samples that failed repeatedly using the standard protocol.