Recently, it has been recognized that accessing information in the mitochondrial DNA (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 restricts the amount of additional sequence that can be obtained, and 2) the need for additional discrimination primarily arises when common hypervariable region 1 and hypervariable region 2 (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 SNP-based approach (Coble et al. 2004; Vallone et al. 2004) has been to identify specific bases that provide resolution in specific common HV1/HV2 types (and related sequences). We investigate several highly relevant datasets in which 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, in order to minimize the potential for problems arising from discovery of mutations that have reportedly been related to disease.
Citation: International Journal of Legal Medicine
Pub Type: Journals
increased forensic discrimination, mitochondrial DNA coding region, single nucleotide polymorphism