Characterization of the Spectrum of Mitochondrial DNA Nucleotide Substitutions in Human Populations in High Altitude Environments

Abstract

Using phylogenetic analysis of the nucleotide sequences of whole mitochondrial genomes (mtDNA), the spectra of germinal nucleotide substitutions (on the L-chain of mtDNA) were reconstructed in highland populations of the Pamirs and Tibet in comparison with regional indigenous groups of West Asia, Northeast Siberia, and South Siberia. No differences were found in the distribution of nucleotide substitution frequencies in the mtDNA spectra depending on the population distribution by altitude. Pyrimidine transitions dominate in all mtDNA spectra, and T → C substitutions are the most frequent among them. Next in frequency in most regional groups are A → G substitutions, but in the Pamir and northeast Asian groups G → A substitutions are prevalent. Of the transversions in all populations studied C → A replacements were found to be predominant, except for the Tibetan one, where A → C substitutions are more frequent. The lack of differences in the distribution of mtDNA mutations in high-altitude and non-highland populations indicates that the structure of mtDNA spectra in human populations is independent of the oxidative stress intensity in mitochondria.