Mitochondrial DNA Polymorphisms

Abstract

The analysis of genetic variation occurring in human mitochondrial deoxyribonucleic acid (mtDNA) has characterised the field of human population genetics since this small molecule has been sequenced in 1981. First analyses were carried out by restriction analysis, and they immediately suggested that mtDNA polymorphisms could allow a phylogenetic reconstruction of the human populations. The technical improvements, which made subsequently easier sequence analyses, allowed to refine the previous results and to understand many aspects of the human origin and of the dispersal of human populations in the world. Interestingly, the variability of mtDNA turned out not to be neutral but to affect the adaptation to the environmental factors (such as climate and diet) and many complex traits such as aging and degenerative diseases. Key Concepts: The analysis of mitochondrial DNA polymorphisms has characterised the last three decades of human genetics. The lack of recombination in mitochondrial DNA leads mtDNA polymorphisms to accumulate sequentially along independent lineages. The availability of a great number of mitochondrial DNA sequences has allowed to find numerous mtDNA polymorphisms. The phylogenesis of mitochondrial DNA polymorphisms allowed to understand many aspects of human evolution and many aspects of the dispersal of human populations. The analysis of mitochondrial DNA polymorphisms in groups of subjects with different complex traits has allowed to highlight that mtDNA polymorphisms are not neutral but they affect many phenotypic traits.