A complex medico-genetic study of West Siberian populations. I. Formulation of a problem. Goals and objectives of the study. Population genetic characteristics of Northern Khanty

Purposes and tasks of the complex medical and genetic study of West-Siberian inhabitants were formulated. Demographic parameters for the North Khanty inhabitants, such as size, dynamics of the tertiary sex ratio, marriage structure and migration processes were presented. Mating and intrapopulation migration patterns are determined by spatial subdivision, because of the vast territory and the traditional way of life, and by isolation by distance. Index of the isolocal endogamy equals to 0.364. The portion of mixed marriages is 22.7% and that of the gametic contribution of immigrants - 7.3%. Inbreeding coefficient by isonymy is 0.00097. Effective population size of the five subpopulations studied as a whole is 25% of their total number.     

"Mixed" endocrine gland cells of the duodenal epithelium in various vertebrate animals and man

Epithelium of the duodenal mucous membrane has been studied in frog, rat and man by means of electron microscopy. Together with typical endocrinocytes, incretory cells of "mixed" type are revealed in the epithelium. They are classified into two types: 1. exo-endocrinic containing in their cytoplasm simultaneously: a) mucous and EC-granules, b) mucous and S-granules, c) granules specific for Paneth's cells and S-granules, d) granules specific for Paneth's cells and L-granules; 2. endocrinocytes with incretory granules of various types: with D and I, with D and EC, with D and L granules. Various ultramicroscopic organization of the "mixed" exo-endocrinic cells is demonstrated. It can be considered as various stages of their differentiation. In cytoplasm of the "mixed" cells of the second type (endocrinic) a constant presence of D-granules is revealed, that is, evidently, characteristic, within the limits of the gastro-entero-pancreatic system, for the cells with two types of the endocrinic granules.     

Prevalence of alleles of polymorphic variants Leu33Pro and Leu66Arg gene ITGB3 among inhabitants of Siberia

The frequency of the polymorphic variant T196C (Leu33Pro, rs5918) of ITGB3 gene was studied in several groups of inhabitants of Siberia, including women with reproductive disorders (n = 186), patients with acute coronary syndrome (n = 330), and population control (n = 858). The frequency of the rare PLA2 allele among residents of Tomsk and Kemerovo was 14.7% and 15.0% respectively. There were no differences in the allele and genotype frequencies of polymorphic variant between patients with acute coronary syndrome and the control group (p = 0.925, p = 0.622). The highest frequency of abnormal PLA2 allele (22.1%) and the PLA2/PLA2 genotype (8.8%) was observed among women who had miscarried, which was significantly different from the frequency of this allele and genotype in the control group (14.7%, p = 0.017; 2.1%, p = 0.0009). Sequencing showed that all samples with the nonspecific band had the polymorphic rs5918 variant and rs36080296 mutations (T216G, Leu66Arg). The frequency of the rs36080296 mutation among the residents of Siberia was 0.51%. Among the women with reproductive disorders, the frequency of rs36080296 was 2.7%, while in the group who suffered from miscarriages, it was 4.4%; this was different from the frequency in the control group (0.08%, p = 0.2 × 10^?6). The accumulation of mutations was also observed among men with acute coronary syndrome (0.6%), but the differences from the control group (0%) had no statistical significance. Thus, the rs36080296 mutation may be a factor in predisposition to miscarriage, especially in combination with the PLAII allele. In addition, the rs36080296 variant among men may be associated with acute cor onary syndrome, which requires further study.     

Association between 242C>T polymorphism of NADPH oxidase p22phox gene (CYBA) and longevity in Russian population

Life span depends on many factors, including the level of reactive oxygen species, like superoxide radical. Superoxide radical is produced from oxygen in the course of the oxidation of NADPH to NADP⁺. The process is catalyzed by NADPH oxidase. In this study, genotype and allele distributions of the C242T (rs4673) polymorphism in the CYBA gene, which encodes the α subunit of NADPH oxidase (p22phox), were examined in the sample of long livers and in the population sample of the city of Tomsk. Statistically significantly higher frequency of T allele among female long livers (34.625%), compared to the females from Russian population (26.32%) was demonstrated (χ² = 5.226; p = 0.022; OR = 1.48). Thus, the T allele is associated with a high life expectancy in females from the Russian population. No such association was observed for males from the same population.     

Haplotype of Y-chromosomes in the Central Asia population

The distribution of alleles and haplotypes of three diallellic Y-specific loci (YAP, DYF155S2, and Tat) in the populations of Kyrgyz, Uzbeks and Tajiks was analyzed. In Kyrgyzes and Uzbeks, a relatively high frequency of the DYF155S2 deletion (20 and 12.5%, respectively) and the C allele at the Tat locus (11.2 and 8.3%, respectively) were revealed. In the populations of southern Kyrgyzes and Uzbeks, two chromosomes carrying the YAP+ allele were detected. In both cases the YAP+ allele was found within the YAP+/DYF155S2+/TatT haplotype. The Tajik population was monomorphic in respect to the polymorphisms studied. The Tajiks demonstrated the presence of only the YAP-/DYF155S2+/TatT haplotype. This haplotype appeared to be most frequent in Kyrgyz (78.8%) and Uzbeks (83.3%). The question on the origin and the distribution of Y-chromosome variants in Eurasia are discussed.     

Genetic demographic characteristics of the rural population of the Tuva Republic: ethnic and tribal composition and sex and age structure]

The ethnic, tribal, sex, and age composition was studied in populations of three districts of the Tuva Republic that were remote from one another. These were the Kyzylskii (the Shinaan population), Todzhinskii, and Bai-Taiginskii raions. The Todzhinskii population was characterized by a mixed ethnic composition dominated by Tuvinians and Russians (62.35 and 35.52%, respectively); the other two districts were only inhabited by Tuvinians. The studied populations differed from one another in the set and proportions of tribal groups--in the Todzhinskii raion, Turkic tribal groups were prevalent, whereas in the Shinaan and Bai-Taiginskii populations, many tribal groups of Mongolian origin were found. The estimations of relationship by isonymy indicated a considerable contribution of geographic isolation to the genetic differentiation of the populations: the estimated relationship between the highland Shinaan and Todzhinskii populations, which are difficult of access, was the minimum (Ri = 0.00262); the coefficients of the relationship by isonymy between the Shinaan and Bai-Taiginskii populations and between the Todzhinskii and Bai-Taiginskii populations were 0.00336 and 0.00483, respectively. All the studied populations were characterized by a "growing" age pyramid; however, the Bai-Taiginskii and Todzhinskii populations showed a tendency to narrowing its base. In addition, these two populations exhibited an unfavorable sex ratio at the reproductive age. The obtained results suggest that the Tuva population is genetically heterogeneous, which is accounted for by the tribal characteristics, the history of populations, and the geographic characteristics of the region.     

Disuniting uniformity: a pied cladistic canvas of mtDNA haplogroup H in Eurasia

It has been often stated that the overall pattern of human maternal lineages in Europe is largely uniform. Yet this uniformity may also result from an insufficient depth and width of the phylogenetic analysis, in particular of the predominant western Eurasian haplogroup (Hg) H that comprises nearly a half of the European mitochondrial DNA (mtDNA) pool. Making use of the coding sequence information from 267 mtDNA Hg H sequences, we have analyzed 830 mtDNA genomes, from 11 European, Near and Middle Eastern, Central Asian, and Altaian populations. In addition to the seven previously specified subhaplogroups, we define fifteen novel subclades of Hg H present in the extant human populations of western Eurasia. The refinement of the phylogenetic resolution has allowed us to resolve a large number of homoplasies in phylogenetic trees of Hg H based on the first hypervariable segment (HVS-I) of mtDNA. As many as 50 out of 125 polymorphic positions in HVS-I were found to be mutated in more than one subcluster of Hg H. The phylogeographic analysis revealed that sub-Hgs H1*, H1b, H1f, H2a, H3, H6a, H6b, and H8 demonstrate distinct phylogeographic patterns. The monophyletic subhaplogroups of Hg H provide means for further progress in the understanding of the (pre)historic movements of women in Eurasia and for the understanding of the present-day genetic diversity of western Eurasians in general.     

MtDNA and Y-Chromosome Lineages in the Yakut Population

The structure of female (mtDNA) and male (Y-chromosome haplotypes) lineages in the Yakut population was examined. To determine mtDNA haplotypes, sequencing of hypervariable segment I and typing of haplotype-specific point substitutions in the other parts of the mtDNA molecule were performed. Y haplogroups were identified through typing of biallelic polymorphisms in the nonrecombining part of the chromosome. Haplotypes within haplogroups were analyzed with seven microsatellite loci. Mitochondrial gene pool of Yakuts is mainly represented by the lineages of eastern Eurasian origin (haplogroups A, B, C, D, G, and F). In Yakuts haplogroups C and D showing the total frequency of almost 80% and consisting of 12 and 10 different haplopypes, respectively, were the most frequent and diverse. The total part of the lineages of western Eurasian origin (Caucasoid) was about 6% (4 haplotypes, haplogroups H, J, and U). Most of Y chromosomes in the Yakut population (87%) belonged to haplogroup N3 (HG16), delineated by the T–C substitution at the Tat locus. Chromosomes of haplogroup N3 displayed the presence of 19 microsatellite haplotypes, the most frequent of which encompassed 54% chromosomes of this haplogroup. Median network of haplogroup N3 in Yakuts demonstrated distinct starlike phylogeny. Male lineages of Yakuts were shown to be closest to those of Eastern Evenks.     

Comparative phylogenetic study of native north Eurasian populations from a panel of autosomal microsatellite loci

Genetic relationships among eighth Siberian and Central Asian ethnic groups were examined using autosomal microsatellite loci. Genetic similarity of Buryats and Evenks, as well as close relationships between Tuvinians and Kyrgyzes, most likely resulting from the Altai-Slavic co-ancestry of their gene pools, was demonstrated. Studies of gene flow in these populations demonstrated that, in general, Turkic ethnic groups of Southern Siberia (Altaians and Tuvinians) were the recipients of more intense gene flow compared to Eastern Siberian populations belonging to Altaic family. The local Buryat populations displayed substantial differences in the direction and the level of deviation of the observed gene diversity from the expected one, which was probably caused by the differences in the degree of isolation and/or in effective population sizes.     

Association of polymorphisms in the human IL4 and IL5 genes with atopic bronchial asthma and severity of the disease

Two polymorphisms in the IL4 (G/C 3'-UTR) and IL5 (C-703T) genes were studied in a sample of families whose probands had atopic bronchial asthma (BA) (66 families, n = 183) and in a group of non-cognate individuals with the severe form of the disease (n = 34). The samples were collected from the Russian population in the city of Tomsk (Russia). Using the transmission/disequilibrium test (TDT), a significant association of allele C-703 IL5 with BA was established (TDT = 4.923, p = 0.007 +/- 0.0007). The analysis of 40 individuals with mild asthma and 49 patients with the severe form of the disease revealed a negative association of genotype GG IL4 (OR = 0.39, 95% CI = 0.15-0.99, p = 0.035), and also a trend towards a positive association of the GC IL4 genotype (OR = 2.52, 95% CI = 0.98-6.57, p = 0.052) with mild BA. There was a concordance of the clinical classification of BA severity with the 'genotype' (McNemar's chi(2) test with continuity correction constituted 0.03, d.f. = 1, p = 0.859). These results suggest that polymorphisms in the IL4 and IL5 genes contribute to the susceptibility to atopic BA and could determine the clinical course of the disease.