Larissa A. Tarskaia

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 Influence of Basal Metabolic Rate on Blood Pressure Among Indigenous Siberians

Hypertension is an important global health issue and is currently increasing at a rapid pace in most industrializing nations. Although a number of risk factors have been linked with the development of hypertension, including obesity, high dietary sodium, and chronic psychosocial stress, these factors cannot fully explain the variation in blood pressure and hypertension rates that occurs within and between populations. The present study uses data collected on adults from three indigenous Siberian populations (Evenki, Buryat, and Yakut [Sakha]) to test the hypothesis of Luke et al. (Hypertension 43 (2004) 555-560) that basal metabolic rate (BMR) and blood pressure are positively associated independent of body size. When adjusted for body size and composition, as well as potentially confounding variables such as age, smoking status, ethnicity, and degree of urbanization, BMR was positively correlated with systolic blood pressure (SBP; P < 0.01) and pulse pressure (PP; P < 0.01); BMR showed a trend with diastolic blood pressure (DBP; P = 0.08). Thus, higher BMR is associated with higher SBP and PP; this is opposite the well-documented inverse relationship between physical activity and blood pressure. If the influence of BMR on blood pressure is confirmed, the systematically elevated BMRs of indigenous Siberians may help explain the relatively high blood pressures and hypertension rates documented among native Siberians in the post-Soviet period. These findings underscore the importance of considering the influence of biological adaptation to regional environmental conditions in structuring health changes associated with economic development and lifestyle change.

Coalescent simulations of Yakut mtDNA variation suggest small founding population

The Yakuts are a Turkic-speaking population from northeastern Siberia who are believed to have originated from ancient Turkic populations in South Siberia, based on archaeological and ethnohistorical evidence. In order to better understand Yakut origins, we modeled 25 demographic scenarios and tested by coalescent simulation whether any are consistent with the patterns of mtDNA diversity observed in present-day Yakuts. The models consist of either two simulated demes that represent Yakuts and a South Siberian ancestral population, or three demes that also include a regional Northeast Siberian population that served as a source of local gene flow into the Yakut deme. The model that produced the best fit to the observed data defined a founder group with an effective female population size of only 150 individuals that migrated northwards approximately 1,000 years BP and who experienced significant admixture with neighboring populations in Northeastern Siberia. These simulation results indicate a pronounced founder effect that was primarily kin-structured and reconcile reported discrepancies between Yakut mtDNA and Y chromosome diversity levels.

Surnames in Siberia: A study of the population of Yakutia through isonymy

We studied the isonymic structure of the Republic of Sakha (Yakutia), in the Russian Federation, using the surname distributions of 491,259 citizens above 18 years registered as residents in 2002. These were distributed in 35 districts and 497 towns and settlements of the Republic. The number of different surnames was 44,625. Matrices of isonymic distances between the 35 districts were tested for correlation with the geographic distance between the population centers of gravity of the districts. We found that, for the whole of Yakutia, Neis distance was correlated with geographic distance (r = 0.693 +/- 0.027). A dendrogram of the 35 districts was built from the distance matrix, using the UPGMA method. The clusters identified by the dendrogram correlate with the geographic position of the districts. The correlation of random inbreeding calculated from isonymy, F(ST), with latitude was positive and highly significant but weak (r = 0.23). So, inbreeding was highest in the Arctic districts, and lowest in the South. Average alpha for 497 towns was 107, for 35 districts it was 311, and for the Republic 433. The value of alpha was higher for Russian than for the local languages. The geographical distribution of alpha, high in the Center and South-East and lower in the North-West, is compatible with the settlement of groups of migrants moving from the South-East toward the center and the North of Yakutia. It is proposed that low-density demic diffusion of human populations results in high inbreeding and may have been a general phenomenon in the early phases of human radiations.

Seasonal variation in basal metabolic rates among the yakut (Sakha) of Northeastern Siberia

Objectives: Previous research has shown that indigenous circumpolar populations have elevated basal metabolic rates (BMRs), yet few studies have explored whether metabolic rates increase during the winter. This study addresses this gap by examining seasonal variation in BMR and its associations with thyroid function and lifestyle factors among the Yakut (Sakha) of Siberia.

Circumpolar Adaptation, Social Change, and the Development of Autoimmune Thyroid Disorders Among the Yakut (Sakha) of Siberia

Alterations in thyroid function appear to play a central role in adaptation to Arctic environments. Increased thyroid activity in indigenous circumpolar populations is associated with upregulated metabolism, including elevated basal metabolic rate (BMR); however, little is known about the possible health consequences of these climate‐induced changes on thyroid function. The focus of the present study is to determine the prevalence of autoimmune thyroid disorders and their lifestyle and metabolic correlates among a sample of indigenous Yakut adults from northeastern Siberia.

Seasonal and Socioeconomic Influences on Thyroid Function Among the Yakut (Sakha) of Eastern Siberia

Previous research has shown that the extreme cold and short day lengths of polar winters promote increased production and uptake of thyroid hormones, resulting in marked declines in free triiodothyronine (fT3). However, this “polar T3 syndrome” has been documented almost exclusively on small samples of male sojourners and little is known about seasonal changes in thyroid function among indigenous circumpolar groups. The present study addresses this gap by examining seasonal changes in thyroid hormone levels among the indigenous Yakut (Sakha) of northeastern Siberia.

Polymorphisms at locus D1S80 and other hypervariable regions in the analysis of Eastern European ethnic group relationships

Background: It has been hypothesized that, whereas many loci are used to generate phylogenetic relationships, the utilization of those that yield the most information could increase the accuracy of any multilocus phylogenetic reconstruction. Among these is the D1S80 hypervariable minisatellite region, which has been shown to be highly polymorphic globally, and it was of interest to compare the nearest neighbours and distant populations of Eastern Europe using the D1S80 polymorphism. Aim: The study evaluated the capacity of the D1S80 locus to discriminate between populations from different ethnic groups in Russia and the Republic of Belarus, revealing the polymorphism parameters of the populations studied. Subjects and methods: Hypervariable D1S80 minisatellite polymorphism was studied in 15 populations, belonging to six distinct ethnic groups from the Russian Federation (Russians, Komis, Maris, Udmurts, Kalmyks, and Yakuts) and the Republic of Belarus (Byelorussians). The data were analysed with other results reported for D1S80 polymorphism among Eastern Europeans, and were analysed together with those previously reported for Eastern European populations for the 3′ApoB, DMPK, DRPLA, and SCA1 hypervariable loci. Genetic diversity analysis was carried out using multidimensional scaling (MDS) of Neis genetic distances. Results: The Eastern Slavonic populations (Russians, Ukrainians, and Byelorussians) are closely associated, and outermost from populations of Asian origin (Kalmyks and Yakuts). The populations that inhabit the Volga–Ural region (Udmurt, Komi, Mari, and Bashkir ethnic groups) revealed intermediate characteristics. Conclusion: The clustering of populations demonstrated here using D1S80 alone coincides with the analysis of five hypervariable region (HVR) loci, and is consistent with linguistic, geographic, and ethnohistorical data. These results are in agreement with most studies of mtDNA, Y-chromosomal, and autosomal DNA diversity in Eastern Europe. The D1S80 locus is convenient for population analyses, and may be used as part of a set of similar markers, which should allow the easy resolution of small differences in population structures.

Objectively measured physical activity and sedentary behaviour of Yakut (Sakha) adults.

Abstract Background: Circumpolar regions are undergoing social and economic transition, which often corresponds to a behavioural transition. Yet, physical activity and sedentary behaviour are rarely objectively measured within these groups. Aim: This study aimed to characterize objectively measured physical activity and sedentary behaviour in a sample of indigenous Siberians. Subjects and methods: Yakut (Sakha) adults (n = 68, 32 men) underwent anthropometry, interviews and wore a triaxial accelerometer for two days. Time spent in moderate-to-vigorous physical activity (MVPA) or sedentary behaviour was calculated using a single axis and also all three axes. Results: Men spent significantly more time in MVPA than women, although no sex difference was found in sedentary behaviour. Participants were far more active and less sedentary when classified using all three axes (vector magnitude) than a single axis. Television viewing time significantly related to sedentary behaviour in men only. Conclusion: The Yakut have gender differences in amount and predictors of physical activity and sedentary behaviour. Triaxial accelerometry is more sensitive to daily physical activity in free living populations than single axis.

The origins of the yakut people: Evidence from mitochondrial DNA diversity

Abstract The Yakuts are a Turkic-speaking population of northeastern Siberia and based on archaeological and ethnohistorical evidence are believed to have originated from Turkic populations in south Siberia. To investigate this model, the HVS-I of the mitochondrial DNA control region was sequenced for 144 Yakut individuals representing seven communities from central Yakutia and compared to HVS-I data for other Asian populations. Haplogroups C and D comprise 75.7% of the Yakut sample, with only 9.7% assigned to west Eurasian lineages. The Ewens-Watterson homozygosity test revealed a significant deviation (P = 0.045) in the observed frequencies of common haplotypes relative to the expected values, indicating the genetic effects of a founder event. This is supported by a fragmented MJ network dominated by high-frequency haplotypes within haplogroups C and D. Nested cladistic analysis identified subhaplogroup D5a as the product of a long distance colonization event and potential founder lineage for the Yakuts, dating to approximately 1,630 years BP. SAMOVA analyses and MDS plot of genetic distances show close genetic affinities between the Yakuts and south Siberian populations, and thus affirming the south origin model.