Genetic demographic characteristics of the rural population of the Tuva Republic: marriage structure and inbreeding]

Marriage structure was studied in three rural populations of the Tuva Republic: the Shinaan population and the populations of Todzhinskii and Bai-Taiginskii raions (districts). The Shinaan and Bai-Taiginskii populations had high levels of endogamy (0.6704 and 0.6050, respectively). In the Todzhinskii population, which was characterized by a mixed ethnic composition, endogamy was 0.3779 for the total population and 0.4626 for Tuvinians; interethnic marriages in this population were rare. The values of marriage assortativeness with respect to birthplace were 19.38, 40.75, 75.87, and 41.87% in the Shinaan, Bai-Taiginskii, all the Todzhinskii populations, and Tuvinian monoethnic marriages in the Todzhinskii raion, respectively. High marriage assortativeness with respect to ethnicity was found. Its values (A') were 91.85 and 93.49% in Tuvinians and Russians, respectively. Tuvinian populations were characterized by high inbreeding. The total (F(it)), random (Fst), and nonrandom inbreeding (Fis) estimated by isonymy were 0.004237, 0.002298, and 0.001944 in the Shinaan population, 0.007292, 0.009448, and -0.002177 in the Bai-Taiginskii population, and 0.003846, 0.004152, and -0.000307 in the Todzhinskii population, respectively (in the latter populations, the F(it), Fst, and Fis values for Tuvinian marriages alone were 0.005000, 0.007222, and -0.002238, respectively). The results obtained indicate that individual territorial groups of Tuvinians retain a high degree of genetic isolation from one another.     

Genetic-demographic characteristics of the rural population of the Republic of Tuva: reproductive indicators and the structure of Crow's indices]

The age limits of the female reproductive function, vital statistics, and Crow's indices were estimated in populations of three districts of the Tuva Republic that were remote from one another. These were the Kyzyl (the Shinaan population), Todzhinskii, and Bai-Taiginskii raions. The monoethnic Shinaan population was characterized by the longest reproductive period (15.88 years) but the lowest average number of pregnancies throughout the reproductive period (5.77); childbirth was an outcome of 86.72% of pregnancies. In the Bai-Taiginskii population, which was also monoethnic but lived in an industrial area of Tuva, these parameters were 12.99 years, 7.06 pregnancies, and 81.97%, respectively. The Todzhinskii population, which was ethnically mixed, exhibited the shortest actual reproductive period (10.72 years) and the greatest average number of pregnancies throughout the reproductive period (7.29), with the proportion of pregnancies ending in childbirth as low as 48.30%. The indices of potential selection and their components related to differential mortality and differential fertility were the following: in the Shinaan population, Itot = 0.59, Im = 0.19, and I(f) = 0.34; in the Bai-Taiginskii population, Itot = 0.48, Im = 0.18, and I(f) = 0.26; and in the Todzhinskii population, Itot = 0.90, Im = 0.23, and I(f) = 0.55. Thus, reproductive parameters in the studied populations of the Tuva Republic were largely determined by the ethnic composition of the population and social factors.     

Polymorphism of immunological and biochemical marker genes in rural populations of the Tuva Republic

This article continues the series of publications on the population genetic structure of the Tuva Republic. The polymorphism of immunological (ABO, MN, and the Dd locus of Rhesus) and biochemical (TF, GC, HP, PGD, PGM1, ACP1, and ESD) marker systems was studied in three rural populations of the Tuva Republic: the Shinaanskii, Todzhinskii, and Bai-Taiginskii populations (the Kungurtug, Toora-Khem, and Teeli villages, respectively). Genetic subdivision of the populations and genetic distances between the Tuvinian populations and the populations of neighboring regions were estimated. Tuvinians were demonstrated to be genetically heterogeneous. Data on their population-genetic structure with respect to several classical marker systems agree with the results obtained for quasigenetic (family names) and molecular (mtDNA) markers. Prolonged isolation of individual populations in the republic promoted formation of specific patterns of gene frequencies in some of them. These patterns account for differences between Tuvinians and other populations belonging to the Altaic language family. Tuvinians in general are genetically closer to Mongolian populations inhabiting the regions bordering the Tuva Republic than to southern Altaians.     

Population structure of rural settlements of Sakha Republic (Yakutia): Surname structure

The distributions of surnames have been studied in 12 rural ethnic territorial groups of Sakha Republic (Yakutia). The populations studied are characterized by considerable accumulation of individual surnames, the surname spectra of representative of different ethnic groups living in the same area substantially overlapping. The random isonymy, migration index, surname diversity, and the surname distribution redundancy index display geographic and ethnic differences. The isonymy relationship coefficients calculated for representatives of individual ethnic groups (Yakuts, Evens, and Russians) and for total populations of the settlements studied are determined by the geographic distances between the compared populations and the intensity of migrations.     

Restriction polymorphism of the major noncoding region of mtDNA in the indigenous population of the TUVA republic]

Mitochondrial DNA sequence variation was examined in three rural populations of the indigenous inhabitants from the Tuva Republic. The frequencies of restriction sites within the D-loop region of mtDNA were determined. The three populations studied demonstrated similar patterns of mtDNA polymorphism. Like other Siberian populations, Tuvinians were characterized by high frequencies of the HaeIII 16517 and AspS9I (Cfr13I) 16516 restriction sites (about 75%). Moreover, in Tuvinians, a relatively low (71 to 81%) frequency of the KpnI 16129 restriction site was observed. The frequency of the mitotype differing from the Cambridge sequence by the HaeIII 16517 and KpnI 16129 sites in Tuvinians was higher than in Mongols and Russians. The features of mtDNA polymorphism point to the similarity between Tuvinians and other Siberian ethnic groups (Sel'kups in particular). This can be explained by the contribution of the Samoyed component, along with the Turkic and Mongoloid ones, to the formation of the Tuvinian ethnic group.     

Analysis of distribution of "mongoloid" haplogroups of mitochondrial DNA among indigenous population of the Tuva Republic

Variation of Mongoloid-specific restriction sites of mitochondrial genome was analyzed in three territorial groups of Tuvinians. Distribution of mitochondrial DNA haplogroups A, B, C, and D on the territory of the Tuva Republic was estimated. The populations studied did not display distinct differentiation in respect to the mtDNA polymorphism. The specific feature of Tuvinian mitochondrial gene pool was the prevalence of only one haplogroup C (over 40%), mainly represented by two mitotypes. The high frequency of this haplogroup makes Tuvinians similar to more northern Siberian populations. On the other hand, the presence of haplogroup B indicates that Tuvinians have affinity to ethnic groups of Central Asia.     

Population structure of rural settlements of Sakha Republic (Yakutia): surname structure

The distributions of surnames have been studied in 12 rural ethnic territorial groups of Sakha Republic (Yakutia). The populations studied are characterized by considerable accumulation of individual surnames, the surname spectra of representative of different ethnic groups living in the same area substantially overlapping. The random isonymy, migration index, surname diversity, and the surname distribution redundancy index display geographic and ethnic differences. The isonymy relationship coefficients calculated for representatives of individual ethnic groups (Yakuts, Evens, and Russians) and for total populations of the settlements studied are determined by the geographic distances between the compared populations and the intensity of migrations.     

Distribution of “Mongoloid” Haplogroups of Mitochondrial DNA Among Indigenous Population of the Tuva Republic

Variation of Mongoloid-specific restriction sites of mitochondrial genome was analyzed in three territorial groups of Tuvinians. Distribution of mitochondrial DNA haplogroups A, B, C, and D on the territory of the Tuva Republic was estimated. The populations studied did not display distinct differentiation in respect to the mtDNA polymorphism. The specific feature of Tuvinian mitochondrial gene pool was the prevalence of only one haplogroup C (over 40%), mainly represented by two mitotypes. The high frequency of this haplogroup makes Tuvinians similar to more northern Siberian populations. On the other hand, the presence of haplogroup B indicates that Tuvinians have affinity to ethnic groups of Central Asia.     

Gene-pool structure of Tuvinians inferred from Y-chromosome marker data

The gene-pool structure of Tuvinians was examined in terms of the composition and frequency of Y-chromosome haplogroups in five geographically distanct populations. In the Tuvinian gene pool, a total of 22 haplogroups were identified with six of these, which were the most frequent (C3c, C3*, N1b, N1c1, Q1a3, and R1a1a). It was demonstrated that eastern regions of Tuva were most different from the other regions in haplotype frequencies. The evaluation of genetic diversity based on the frequencies of biallelic haplogroups and YSTR haplotypes revealed very high diversity values for all samples. In general, the genetic diversity values identified in Tuvinians were the highest for the indigenous ethnic groups of Siberia. The evaluation of the genetic differentiation of the samples examined using the analysis of molecular variance (AMOVA) showed that the gene pool of Tuvinians was relatively poorly differentiated with respect to haplogroup frequencies. Phylogenetic analysis within haplogroup N1b revealed strong founder effect, i.e., reduced diversity and star-like phylogeny of the median network of haplotypes, which formed a separate subcluster exclusive to Tuvinians. It was demonstrated that, in Tuvinians, haplogroup N1c1 was the most heterogeneous in haplotype profile and consisted of three different haplotype clusters, demonstrating considerable differences of western population from the rest of the Tuva populations. Phylogenetic analysis of haplogroups revealed common components for Tuvinians, Khakasses, Altaians, and Mongols.     

Microsatellite haplotypes of the Y-chromosome demonstrate the absence of subdivisions and presence of several components in the Tuvinian male gene pool

The haplotype analysis of seven Y-chromosome microsatellites in three regional populations of Tuvinians revealed high intrapopulation variation in the male gene pool of the modern population of the Tuva Republic. In total, 49 haplotypes were found in 111 individuals; only four haplotypes occurred at a frequency higher than 5%. High genetic diversity (H = 0.935) suggested a high power of discrimination for the Y-chromosome haplotypes. The analysis of molecular variance (AMOVA) and other data did not reveal subdivision of the Tuvinian population with respect to Y-chromosome haplotypes. Most haplotypes found in Tuvinians formed two lines. Line A included approximately 64% of the haplotypes found, line B, approximately 24%. A putative ancestral haplotype of line B was similar to a haplotype most common in modern Caucasoids (Md = 3), whereas a putative ancestral haplotype of line A proved to be distant from the ancestral haplotype of line A and haplotypes common for Caucasoids and Mongoloids. Estimates of the age of the Y-chromosome lines showed that the male gene pool of modern Tuvinians originated in the late Paleolithic or Neolithic period. With two methods, the age of line A was estimated at 3500 or 18,000 years and the age of line B was approximately at 5500 or 15,000 years. Considering the less conservative estimates to be more reliable, line B was assumed to originate from the ancient Caucasoid population of the Tuva region. The more widespread and evolutionarily younger line A was associated with the peopling region by ancient Mongoloid tribes of the Turkic language group in the Hun-Sarmatian period.     

新疆阿勒泰地区图瓦人与邻近人群遗传关系初探

在中国新疆阿勒泰地区哈纳斯景区内, 生活着一个特殊的人群—— 新疆图瓦人。他们在50年代初期第一次民族识别过程中被认定为蒙古族, 但他们自认为与蒙古人具有不同的历史渊源。为了探讨新疆图瓦人的族源问题和阐明其与邻近人群的遗传学关系, 文章采集了新疆阿勒泰地区150份男性图瓦人样本, 对其Y染色体非重组区的14个标记位点进行了分型, 构建了11种单倍型群。结果显示, 新疆图瓦人具有高频率的K^*-M9 和Q^*-M242单倍型群, 这两个单倍型群在俄罗斯图瓦人中也具有较高的频率, 而在蒙古人群和哈萨克人群中的频率则较低。主成分分析和多维尺度分析均显示新疆图瓦人与蒙古人和哈萨克人遗传上相隔较远。系统分子进化分析也表明新疆图瓦人位于与周围人群相隔较远的分化枝上。依据这些结果, 文章认为新疆图瓦人是与邻近人群如蒙古人和哈萨克人有较大遗传差异的人群。     

Genetic and demographic characteristics of rural populations of Altaĭ republic: sex-age composition, surname and tribal structure

The sex, age, tribal, and surname compositions of the populations of three villages of Altai Republic, Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion) have been studied. Altaian populations are characterized by a high proportion of persons under 20 years of age (35.3-46.1%); however, there is a tendency towards a narrow base of the sex-age pyramid. The sex ratios in the total populations and in individual age groups are unfavorable. The rural populations studied differ in the spectrum and pattern of surname accumulation. The Kurmach-Baigol population (which consists of Northern Altaians) considerably differs from the Beshpeltir and Kulada populations (which are mostly Southern Altaian) with respect to the calculated parameters characterizing the population structure (random isonymy, migration index, the parameter of tribe diversity, entropy, and the redundancy of surname distribution). Isonymy coefficients of relationship between individual populations have been calculated from the data on tribes (surnames). These coefficients for pairs of populations are the following: for the Beshpeltir and Kulada populations, 0.3035938 (0.0000443 and 0.0000378 for the Altaian and total populations, respectively); for the Beshpeltir and Kurmach-Baigol populations, 0.0026788 (0.0000172 and 0.0000121 for the Altaian and total populations, respectively); and for the Kulada and Kurmach-Baigol populations, 0.0054811 (no common surnames have been found).     

Genetic demographic description of the Ust-Aldan rural population of Sakha Republic (Yakutia): ethnic, sex, and age compositions, vital statistics, and surname structure

Information on the sex, age, and ethnic compositions; reproductive parameters; intensity of natural selection (Crow's indices); and surname diversity of three rural populations (the Byadi, Dyupsya, and Cheriktey villages) of the Ust-Aldan ulus (district) of Sakha Republic (Yakutia) has been analyzed. The rural Yakut population of the Ust-Aldan ulus is demographically young (the mean age 25-31 years) and characterized by low outbreeding, unfavorable sex ratio in both prereproductive and reproductive ages, and high fertility (3.58-5.45 children surviving until the reproductive age per woman that has completed the reproductive period), although the actual reproductively active period is shorter than half its physiological duration. In the structure of total selection, the differential-fertility component is considerably greater than the differential-mortality component (Itot = 0.625, Im = 0.093, and If = 0.487). In the villages studied, some surnames are accumulated (45-65% of the population have five most frequent surnames), which determines the low surname diversity (alpha = 11.62-25.19) and high random isonymy (Ir = 0.0391-0.0823).     

Population demographic structure of the city of Ulan Ude: Ethnic composition and age at marriage

The marriage structure of the population of Ulan Ude, the capital of Buryat Republic, which is characterized by a mixed ethnic composition, has been studied. Differences between Ulan Ude districts in a number of genetic demographic parameters have been found. In ethnic terms, the city district populations differ from one another in the number of ethnic groups and the proportions of the largest groups (Russians and Buryats). In the total Ulan Ude population, the proportions of Russian men and women among persons contracting marriages are 71.44 and 73.79%, respectively; those of Buryat men and women are 23.36 and 22.79%, respectively. The total proportion of all other ethnic groups among both men and women contracting marriages is no more than 5.2%. The mean ages at first marriage in both indigenous and immigrant populations of Ulan Ude are relatively old; these values are 25.9 and 24.72 years for Buryat men and women and 24.86 and 22.69 for non-indigenous men and women, respectively.     

Study of the most often encountered allele of the HLA-B27 gene in Tuvinian and Russian inhabitants of Western Siberia

HLA-B27 gene frequencies and allelic polymorphism were studied in two Siberian ethnic groups: Russians from Novosibirsk (western Siberia) and Tuvinians from Kyzyl (southern Siberia). The HLA-B27 frequencies were determined by means of serologic typing of HLA antigens in 198 Tuvinians and 288 Russians. Molecular typing was performed via hybridization of oligonucleotide probes with amplified DNAs obtained from 30 HLA-B27-positive Russians and 11 HLA-B27-positive Tuvinians. The HLA-B27 gene frequencies in Tuvinians and Russians were 5.5 and 10.4%, respectively. Molecular variants of the HLA-B27 gene were studied in Tuvinians for the first time. The proportions of the HLA-B2705 and HLA-B2704 alleles were found to be 64 and 36%, respectively, in the population studied. The presence of the HLA-B2704 allele indicates a Mongoloid origin of Tuvinians. In the Russian population of Novosibirsk, the HLA-B2704 allele was not found, whereas the proportions of the HLA-B2705 and HLA-B2702 alleles were 76.2 and 23.8%, respectively, which is characteristic of Caucasoid populations.     

Genetic differentiation of the Tuva population with respect to the Alu insertions]

Polymorphism of three rural populations of the Tuva Republic was examined using a set of five autosomal Alu insertions at the ACE, PLAT, PV92, APOA1, and F13B loci. The allele frequency distribution patterns revealed in Tuvinians were typical to Mongoloid populations of Asia and were characterized by relatively high frequency of the Alu-repeat insertion at the PV92 and F13B loci along with relatively low insertion frequency at the APOA1 locus. With respect to the test systems used, Tuvinian populations examined displayed high levels of genetic diversity. The mean expected heterozygosity values in the populations of Kugurtug, Toora-Khem, and Teeli were 0.433, 0.407, and 0.437, respectively. The level of genetic diversity in the pooled Tuvinian sample was 0.432. The coefficient of genetic differentiation in the three populations studied was 1.45 pointing to relatively low level of genetic subdivision of the indigenous Tuvinian populations. However, estimates of genetic differentiation of the Tuvinian gene pool made by use of the Alu-repeat system were higher compared to those performed using classical protein systems, mtDNA, or Y-chromosomal haplotypes. Even though Tuvinian populations were characterized by common gene pool, some features specific to Western Tuvinian population could be distinguished. These features could be associated with higher contribution of the Caucasian component to the gene pool of this population. Phylogenetic analysis demonstrated close genetic relationships between the Tuvinian and Altaic ethnic populations.     

Genetic demographic description of the Ust-Aldan rural population of Sakha Republic (Yakutia): migrations and marriage structure

Migrations, dynamics of the gametic structure of rural populations, and marriage structure with respect to birthplaces and inbreeding estimated from isonymy have been studied in the Ust-Aldan ulus (administrative district) of Sakha Republic (Yakutia). The villages studied (Byadi, Dyupsya, and Cheriktey) are characterized by intense migration; however, the migration radius is small (most migrations occur within the district). The rural populations studied differ in the intensities and directions of gamete flows and their dynamics. There is no substantial gamete flow into the Ust-Aldan population from outside Sakha Republic. About 50% of marriages contracted in this population are homolocal (between residents of the same district); the endogamy is low (15%). In most cases of heterolocal marriages (contracted between residents of different districts), one of the spouses is a local resident. The inbreeding estimated from isonymy is FTT = 0.002930 in Yakuts; it is mainly accounted for by the nonrandom component (FIS = 0.002232 and FST = 0.000700).     

A study of surnames in China through isonymy

The isonymy structure of 1.28 billion people registered in China's National Citizen Identity Information System was studied at the provincial, prefectural, and county administrative division levels. The isonymy was 0.026 for China as a whole. The average value of isonymy was 0.033 for the 30 provinces, 0.035 for the 334 prefectures, and 0.040 for the 2811 counties. The isonymy in China was much higher than in other countries. This finding may be partly explained by the low number of surnames in the Chinese language. Two regional features can be identified from the geographic distributions of isonymy. One feature is that the middle and lower reaches of the Yangtze River had the lowest values of isonymy at both the provincial and county levels. The second feature is that most counties with the highest values of isonymy were distributed in the provinces with high proportions of ethnic minorities. According to the dendrogram of surname distances, several clusters could be identified. Most provinces in a cluster were conterminous with one another. The one exception could be explained by demic migration called "braving the journey to the northeast of China." Isolation by distance could be detected because the correlation coefficients between Nei's distance and the geographic distances at the provincial, prefectural, and county levels were 0.64, 0.43, and 0.37, respectively. Human behaviors in Chinese history that may have caused these results have been discussed, including cultural origin, migration, residential patterns, and ethnic distribution.     

Analysis of allele frequency of seven microsatellite loci of Y chromosome in three Tuva populations

The allele frequency distribution of seven microsatellite loci of the nonrecombining region of the Y chromosome (Y-STRs) was analyzed in three geographically distant indigenous populations of the Tuva Republic. The populations did not differ in allele frequency distribution of the seven Y-STRs. The Y-chromosome microsatellite loci in Tuvinians showed a high diversity (H = 0.575) that was nearly identical in all three populations. The genetic distance Ddm between the three populations was low, suggesting no subdivision of the modern male population of Tuva. Estimates of the period of linear changes in Ddm showed that Y-chromosome microsatellites can be used to reconstruct evolutionary events dating back no more than 40,000-50,000 years. The problems of human population phylogeny are discussed on the basis of data on Y-chromosome STRs.     

Genetic and demographic characteristics of rural populations of Altai Republic: Sex-Age composition,surname and tribal structure

The sex, age, tribal, and surname compositions of the populations of three villages of Altai Republic, Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion) have been studied. Altaian populations are characterized by a high proportion of persons under 20 years of age (35.3–46.1%); however, there is a tendency towards a narrow base of the sex-age pyramid. The sex ratios in the total populations and in individual age groups are unfavorable. The rural populations studied differ in the spectrum and pattern of surname accumulation. The Kurmach-Baigol population (which consists of Northern Altaians) considerably differs from the Beshpeltir and Kulada populations (which are mostly Southern Altaian) with respect to the calculated parameters characterizing the population structure (random isonymy, migration index, the parameter of tribe diversity, entropy, and the redundancy of surname distribution). Isonymy coefficients of relationship between individual populations have been calculated from the data on tribes (surnames). These coefficients for pairs of populations are the following: for the Beshpeltir and Kulada populations, 0.3035938 (0.0000443 and 0.0000378 for the Altaian and total populations, respectively); for the Beshpeltir and Kurmach-Baigol populations, 0.0026788 (0.0000172 and 0.0000121 for the Altaian and total populations, respectively); and for the Kulada and Kurmach-Baigol populations, 0.0054811 (no common surnames have been found).Translated from Genetika, Vol. 41, No. 2, 2005, pp.254–260.Original Russian Text Copyright © 2005 by Kucher, Tadinova, Puzyrev.