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Forensic identification by DNA fingerprinting and mitochondrial DNA typing
B Rerkamnuaychoke1, W Chantratita, U Jomsawat
1Human Genetics Unit, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Summary
Forensic identification using short tandem repeats (STRs) and mitochondrial DNA (mtDNA) typing proved effective for a postmortem sample. mtDNA sequencing provided 100% homology, confirming identity when STR analysis was incomplete.
Area of Science:
- Forensic Science
- Genetics
- Molecular Biology
Background:
- Short tandem repeats (STRs) are highly polymorphic markers in the human genome.
- Mitochondrial DNA (mtDNA) typing utilizes conserved sequences within maternal lineages.
- Polymerase chain reaction (PCR) facilitates DNA analysis for forensic identification.
Purpose of the Study:
- To evaluate the efficacy of STR and mtDNA typing for personal identification of a postmortem muscle biopsy sample.
- To compare DNA profiles with a relative's genotype for identification.
Main Methods:
- Analysis of 9 STR loci and mtDNA sequencing of hypervariable region I (HV I).
- Comparison of DNA profiles from a muscle biopsy (2 months postmortem) with a relative's genotype.
- Utilized polymerase chain reaction (PCR) for DNA amplification.
Main Results:
- The DNA profile shared common alleles with the relative, but only 60% of alleles were identifiable.
- mtDNA sequencing of HV I showed 100% homology with the relative's DNA.
- STR analysis alone provided incomplete identification, while mtDNA confirmed the relationship.
Conclusions:
- Personal identification can be precisely achieved by combining DNA profile data and mtDNA typing.
- mtDNA typing is a valuable tool for forensic identification, especially when nuclear DNA (STR) analysis is compromised.
- The study highlights the complementary roles of STR and mtDNA analysis in forensic casework.