Abstract—Nucleotide sequence variability of whole mitochondrial genomes (mtDNA) was analyzed and mutation spectra were reconstructed (by L-chain of mtDNA) in four regional groups of indigenous populations representing Northeastern and Southern Siberia, Western Asia, and the Americas. The pyrimidine transitions were found to be predominant in all groups; of these, the T→C substitutions were most frequent. The second most common in all regional groups (except Northeastern Siberia) are A→G substitutions. Of the transversions, in all the populations studied the C→A substitutions dominate. Between-regional differences in the distribution of nucleotide substitutions in mtDNA mutation spectra were not detected. However, a significant (4-fold) decrease in the number of mutations in mitochondrial gene pools was detected in the indigenous population of Northeastern Siberia compared to other regions. This may be due to the increased effect of negative selection on mtDNA in the Far North environment, which prevents the accumulation of new mutations, and genetic drift, which is most pronounced in isolated and small populations of Northeastern Siberia. Because of the lack of between-regional differences in mtDNA mutation spectra, the results we obtained do not allow us to confirm the hypothesis that the T→C substitution frequency is a molecular marker of the level of oxidative stress in mitochondria (at least for germline mutations).

摘要— 分析了代表西伯利亚东北部和南部、西亚和美洲的四个原住民区域群体的整个线粒体基因组 (mtDNA) 的核苷酸序列变异性并重建了突变谱（通过 mtDNA 的 L 链）。发现嘧啶转变在所有组中均占主导地位；其中，T→C 替换最为频繁。在所有区域组（西伯利亚东北部除外）中第二常见的是 A→G 替换。在所有研究的人群中，C→A 置换占主导地位。未检测到 mtDNA 突变谱中核苷酸取代分布的区域间差异。然而，与其他地区相比，西伯利亚东北部土著居民的线粒体基因库突变数量显着（4 倍）减少。这可能是由于远北环境中线粒体DNA负选择的影响增加，这阻止了新突变的积累，以及遗传漂变，这在西伯利亚东北部的孤立和小种群中最为明显。由于 mtDNA 突变谱缺乏区域间差异，我们获得的结果不允许我们证实 T→C 取代频率是线粒体氧化应激水平的分子标记的假设（至少对于种系突变）。这可以防止新突变的积累和遗传漂变，这在西伯利亚东北部孤立的小种群中最为明显。由于 mtDNA 突变谱缺乏区域间差异，我们获得的结果不允许我们证实 T→C 取代频率是线粒体氧化应激水平的分子标记的假设（至少对于种系突变）。这可以防止新突变的积累和遗传漂变，这在西伯利亚东北部孤立的小种群中最为明显。由于 mtDNA 突变谱缺乏区域间差异，我们获得的结果不允许我们证实 T→C 取代频率是线粒体氧化应激水平的分子标记的假设（至少对于种系突变）。