Frequency of heteroplasmy in HVI and HVII mitocondrial genome regions in a population sample of Maracaibo, Venezuela

Abstract

Background: The study of the polymorphisms of the hypervariable regions I and II (HVI and HVII) of the mitochondrial DNA (DNAmt) has become an invaluable tool for forensic science, in some occasions a certain individual can present more than one type of mtDNA, this phenomenon is known as Heteroplasmy, this coexistence of two or more populations of DNAmt can occur in a single mitochondrion, cell or individual, which can increase the complexity in interpreting the results of forensic expertise. Objectives: Analyze the frequency of heteroplasmy in the HVI and HVII regions of the mitochondrial genome of 50 randomly selected DNA samples from the Maracaibo population. Methodology: The hypervariable regions were amplified by PCR, then sequenced using the Sanger method and the fragments were separated by capillary electrophoresis, differences were reported with respect to the Cambridge reference sequence. Results: 26% of the samples presented heteroplasmy in the HVI region, while in the HVII region it was 52%. Conclusions: The appearance of heteroplasmy in a certain sequence does not invalidate the use of mitochondrial DNA analysis for forensic purposes, depending on the complexity of the case to assess heteroplasmy can be of great help.