The use of mitochondrial DNA single nucleotide polymorphisms to assist in the resolution of three challenging forensic cases.

Mitochondrial DNA (mtDNA) single nucleotide polymorphisms (SNPs) in an 11-plex assay were typed in three missing person cases involving highly degraded human remains. Unlike the traditional forensic approach to analyzing mtDNA which focuses on sequencing portions of the noncoding Control Region, this assay targets discriminatory SNPs that reside principally in the coding region. In two of the cases, the SNP typing successfully excluded one of two reference families that could not be excluded on the basis of mtDNA hypervariable region sequencing alone, and resulted in the final resolution of both decades-old cases. In a third case, SNP typing confirmed the sorting and reassociation of multiple commingled skeletal elements. The application of a specific mtDNA SNP assay in these cases demonstrates its utility in distinguishing samples when the most common Caucasian hypervariable region type is encountered in forensic casework.

Application of low copy number STR typing to the identification of aged, degraded skeletal remains.

Low copy number (LCN) STR typing was successfully applied to four interesting cases during developmental validation of the approach for degraded skeletal remains. Specific questions were addressed in each case, with the acquisition of STR data largely serving as additional confirmatory or investigatory information in any specific situation, and not necessarily providing the definitive evidence to establish identity. The cases involve missing U.S. service members from World War I, World War II, and the Vietnam War. The variety of these cases, in terms of the questions addressed, the age of the remains, and the type of reference material available for comparison, demonstrates the broad utility of LCN STR typing in the identification of degraded skeletal remains from missing persons.

Effective strategies for forensic analysis in the mitochondrial DNA coding region.

Recently, it has been recognized that accessing information in the mtDNA coding region can provide additional forensic discrimination with respect to the standard typing of the D-loop region, augmenting the sometimes rather limited forensic power of mtDNA testing. Here, we discuss considerations relating to maximally effective approaches for recovering additional discrimination in the coding region, bearing in mind that (1) DNA quality and quantity in typical mtDNA casework usually restrict the amount of additional sequence that can be obtained, and (2) the need for additional discrimination primarily arises when common HV1/HV2 types are encountered. Most investigators have sought additional discrimination by sequencing short segments of coding region that are thought to be particularly variable. Unfortunately, efforts in this regard have generally failed to appreciate that most variation in the coding region is redundant with information already present in HV1/HV2 and have therefore overvalued the potential of this approach for providing additional discrimination. An alternative single nucleotide polymorphism-based approach [Int J Legal Med 118:137-146, 2004] has been to identify specific bases that provide resolution in specific common HV1/HV2 types (and related sequences). We investigate several highly relevant data sets wherein the latter approach performs appreciably better than sequencing selected short portions of the coding region. This is true even when only synonymous variation is targeted to minimize the potential for problems arising from discovery of mutations that have reportedly been related to disease.

The gander disaster: dental identification in a military tragedy.

The authors record the contributions of dentistry to the identification of victims of one of the most significant disasters in aviation and U.S. military history--the December 1985 crash of a DC-8 charter airliner near Gander, Newfoundland (now known as Newfoundland and Labrador), Canada, which killed 248 Army personnel and 8 crewmembers. Most of the dental records of the military victims were destroyed in the crash, and, as a result, this loss hampered dental identification. Nevertheless, dental identification was the primary means of identification for many because a very high percentage of the bodies were severely burned and fragmented. Many phases of the U.S. identification efforts have been reported, but the dental-investigation aspects have been mentioned only in passing. Therefore, this article documents the dental team's organization, methodology, and a variety of remarkable problems that the team encountered.