Sequence polymorphism and haplogroup distribution of mitochondrial DNA control regions HVS1 and HVS2 in Lagos State, Nigeria, population

Sequence polymorphism of mtDNA in a Lagos population

Abstract

Mitochondrial DNA (mtDNA) consists of circular DNA molecules with about 16.5kbp, with smaller fragments of 1200bp known as the control region. Knowledge of mtDNA variation within populations has been employed in forensic and molecular anthropology studies. This study investigated the polymorphic nature of the two hypervariable segments of the mtDNA i.e. HVS1 and HVS2, and determined the haplogroup distribution among individuals resident in Lagos, Nigeria. Peripheral blood was obtained from sixty maternally unrelated individuals. DNA was extracted and amplified using specific primers. DNA amplicons were sequenced, sequenced data were aligned and compared to the revised Cambridge Reference Sequence (rCRS) GenBank Accession number: NC_012920.1) using BioEdit 7.2 software. Results showed 61 and 52 polymorphic nucleotide positions for HVS1 and HVS2, respectively. While three indels mutation were recorded for HVS1, seven were recorded for HVS2. Transition mutations (49.2%) predominate nucleotide change was observed. Genetic diversity values for HVS1 and HVS2 were estimated to be 84.21 and 90.4%, respectively while, random match probability was 0.17% for HVS1 and 0.89% for HVS2. The study showed mixed haplogroups specific to the African (L1-L3) and the Eurasians (U and H) lineages. New polymorphic sites obtained from the study could be used for human identification purposes.