MITOCHONDRIAL DNA PHYLOGEOGRAPHY AND HUMAN POPULATION GENETICS: INSIGHTS INTO MIGRATION, DEMOGRAPHY, AND EVOLUTION

Abstract

Mitochondrial DNA (mtDNA) has been widely used to trace maternal ancestry and investigate population structure, migration, and demographic changes. Its high copy number, predominantly maternal inheritance, and relatively rapid sequence evolution have also made it useful when DNA preservation is poor, including forensic and ancient samples. Much of what is known about the global distribution of maternal lineages initially came from control region sequences and haplogroup frequencies. Complete mitogenomes have improved the resolution of these studies. Modern sequencing has also changed the study of variations within individuals. Low-level heteroplasmy, once difficult to detect systematically, can now be examined across large datasets, raising new questions about maternal transmission, somatic mutations, and the influence of the nuclear genome on mitochondrial variation. In forensic genetics, the high copy number of mtDNA remains particularly useful when biological material is highly degraded, or nuclear DNA recovery is poor. At the same time, mtDNA reflects only a single maternal lineage and should not be considered a comprehensive account of population ancestry. Evolutionary interpretations can be influenced by factors like the founder effect, genetic drift, selection, heteroplasmy, NUMTs, and the calibration of molecular clocks. The analysis of mtDNA is being enhanced by integrating genome-wide and ancient DNA, archaeological findings, and supplementary data. The inclusion of data from underrepresented and indigenous groups, advancements in sequencing technology, and insights into mitonuclear interactions are expected to uncover aspects of maternal lineage that are not well-represented in existing mitochondrial reference datasets.​