Mitochondrial DNA analysis and typing
Mitochondrial DNA analysis and typing (Forensic Science)
Mitochondria are cellular organelles responsible for bodily energy production. Human mitochondria contain a circular genome of 16,569 bases, the bulk of which encodes thirty-seven RNA (ribonucleic acid)/proteins. The remaining segment, termed the control region, regulates DNA (deoxyribonucleic acid) replication and transcription.
The noncoding nature of the control region has allowed mutations (or polymorphisms) to accumulate over time, most of which are located in two hypervariable regions: HV1 and HV2. Scientists conduct mitochondrial DNA (mtDNA) typing by obtaining the HV DNA sequences and comparing them with the reference sequence known as the Anderson sequence or the Cambridge Reference Sequence. Differences between the sample mtDNA and the reference sequence are reported based on the type of polymorphism (base change, insertion/deletion) and its nucleotide position. For instance, if mtDNA from a hair has a C at position 152 while the reference sequence has a T, the DNA type (termed a haplotype) for that individual would be reported as 152C. Any other polymorphisms are reported as well, and the frequency of that haplotype in humans can be determined.
MtDNA typing does not have the discriminatory power of nuclear DNA analysis; however, there are instances in which mtDNA is the only DNA recoverable, particularly from materials of forensic interest. This can be the case for shed hair, aged bone or teeth, nails, and mummified...
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Further Reading (Forensic Science)
Butler, John M. Forensic DNA Typing: Biology, Technology, and Genetics of STR Markers. 2d ed. Burlington, Mass.: Elsevier Academic Press, 2005.
Cox, Margaret, et al. The Scientific Investigation of Mass Graves. New York: Cambridge University Press, 2008.
Hummel, Susanne. Ancient DNA Typing: Methods, Strategies, and Applications. New York: Springer, 2002.
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