A private allele ubiquitous in the Americas.

The three-wave migration hypothesis of Greenberg et al. has permeated the genetic literature on the peopling of the Americas. Greenberg et al. proposed that Na-Dene, Aleut-Eskimo and Amerind are language phyla which represent separate migrations from Asia to the Americas. We show that a unique allele at autosomal microsatellite locus D9S1120 is present in all sampled North and South American populations, including the Na-Dene and Aleut-Eskimo, and in related Western Beringian groups, at an average frequency of 31.7%. This allele was not observed in any sampled putative Asian source populations or in other worldwide populations. Neither selection nor admixture explains the distribution of this regionally specific marker. The simplest explanation for the ubiquity of this allele across the Americas is that the same founding population contributed a large fraction of ancestry to all modern Native American populations.

[The effect of marriage migration on the genetic structure of the Taimyr Nganasan population: genealogical analysis inferred from MtDNA markers].

The marriage structure of Nganasans during the time period from 1796 to 1991 and genealogy of carriers of mitochondrial DNA haplotypes was studied in a sample of 280 individuals. It was shown that, from the beginning of its formation to the late 1970s, the population exhibited high endogamy (1976, 83.8%; 1926, 88.4%; 1976, 74.3%). The main source of traditional marriage migration (preferentially female) was populations of Entsy and, indirectly, Nentsy. Intense assimilation of Nganasans by the immigrant population, and to a lesser extent, by Dolgans, in the second half of the 20th century resulted in a reduction of endogamy index in Avam Nganasans to 42.5% by 1991. Assimilation by the immigrants was predominantly paternal, promoting preservation of the historically formed genetic diversity of the Nganasan mitochondrial gene pool. Genealogical analysis of mtDNA haplotypes showed that a relatively high total frequency of Western Eurasian mtDNA haplogroups (20.4%) in the Mongoloid (according to anthropological type) Nganasan population is explained not only by the common ethnic origin with Entsy and Nentsy, but also by direct marriage migration from the Entsy population and indirect marriage migration, from the Nentsy population. This migration led to accumulation of Entsy-Nentsy maternal lineages in the genealogy of Avam Nganasans (38.9% of the total number). Of all mtDNA haplotypes, 28.6% were introduced to Avam Nganasans by female Entsy and Nentsy, whereas the total frequency of these haplotypes was 0.204. Genetic diversity of mitochondrial DNA haplotypes was 0.935.

[A method for estimating penetrance of pathogenic mutations in a mitochondrial genome]. / Metod otsenki penetrantnosti patogennykh mutatsii mitokhondrial'nogo genoma.

Variation in the manifestation age is typical of many mitochondrial diseases. The estimation of penetrance of pathogenic mutations causing such diseases is usually conducted on samples of individuals whose age exceeds the maximum age of the disease manifestation. In the case of rare diseases, samples of sufficient size sometimes cannot be formed. In this study, we propose a method for estimating penetrance involving individuals of any age. The efficiency of the method is demonstrated using Leber hereditary optic neuropathy as an example. It is shown that the method provides an unbiased estimate of penetrance and considerably reduces the error of this estimate in comparison with a sample including individuals whose age exceeds the maximum age of disease manifestation.