Heteroplasmy in Hair: Study of Mitochondrial DNA Third Hypervariable Region in Hair and Blood Samples
Mitochondrial DNA (mtDNA) analysis has proved useful for forensic identification especially in cases where nuclear DNA is not available, such as with hair evidence. Heteroplasmy, the presence of more than one type of mtDNA in one individual, is a common situation often reported in the first and second mtDNA hypervariable regions (HV1/HV2), particularly in hair samples. However, there is no data about heteroplasmy frequency in the third mtDNA hypervariable region (HV3). To investigate possible heteroplasmy hotspots, HV3 from hair and blood samples of 100 individuals were sequenced and compared. No point heteroplasmy was observed, but length heteroplasmy was, both in C-stretch and CA repeat. To observe which CA “alleles” were present in each tissue, PCR products were cloned and re-sequenced. However, no variation among CA alleles was observed. Regarding forensic practice, we conclude that point heteroplasmy in HV3 is not as frequent as in the HV1/HV2.
Document Type: Research Article
Affiliations: 1: UNESP, São Paulo State University, School of Pharmaceutical Sciences, Rodovia Araraquara-Jaú, Km 01, Campus, 14801-902 Araraquara, SP, Brazil. 2: USP, University of São Paulo, School of Pharmaceutical Sciences, Av. Prof. Lineu Prestes, 580 Bl. 17, Cidade Universitária, 05508900 São Paulo, SP, Brazil. 3: USP, University of São Paulo, School of Dentistry, Av. Prof. Lineu Prestes, 2227, Cidade Universitária, 05508900 São Paulo, SP, Brazil.
Publication date: May 1, 2010