Genetic and demographic characteristics of rural populations of Altai Republic: The marriage structure dynamics

The dynamics of population marriage structure in the period from 1951 to 1997 has been studied in three villages of Altai Republic: Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion). These populations have been found to differ from one another in the intensity and direction of migration, as well a its temporal pattern with respect to the birthplaces and ethnicity of persons contracting marriages. Periods of active incorporation of non-Altaian (mostly Slavic) ethnic components into the gene pools of the Beshpeltir and Kurmach-Baigol populations have been detected. The geographic distributions of the birthplaces of men and women contracting marriages are different. Therefore, migration has different effects on the genetic diversity of the Y-chromosomal and mitochondrial-DNA pools. No isonymic marriages have been found in the Altaian populations studied; however, an increase in the random component of inbreeding has been observed.Translated from Genetika, Vol. 41, No. 2, 2005, pp. 261–268.Original Russian Text Copyright © 2005 by Kucher, Tadinova, Puzyrev.     

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.     

Genetic and demographic structure of Russian populations from the Tver' and Rostov regions

Based on the data from 569 questionnaires collected in Udomlya and Ostashkov raions of Tver oblast and 436 questionnaires collected in Tsimlyansk and Dubovsk raions of Rostov oblast, genetic demographic characteristics and Crow's index for urban and rural populations of these regions were calculated. The data obtained were compared with those for other Russian populations obtained earlier.     

Genetic structure in urban and rural populations of Apodemus agrarius in Poland

The aims of this study were (i) to determine the genetic variability of the striped field mouse (Apodemus agrarius Pallas, 1771) population in the area of the Warsaw conurbation and the genetic differentiation among local populations of this species within the city, and (ii) to examine the influence of the degree of isolation on the appearance of such genetic structure. Comparison of the genetic structure of the urban population with that of populations inhabiting rural areas was intended to shed light on the depth of genetic changes in this species caused by life in an urban environment. Eight microsatellite loci were used for genotyping and these molecular analyses were successfully performed for 269 individuals. Genetic differentiation (F_ST) was much higher in the case of the urban population. STRUCTURE analysis indicated that this population was subdivided into several local populations, whereas for the rural locations, the highest likelihood was for a single genetic group (one genetically unstructured population). Moreover, in contrast to the rural population, we found no isolation by distance in the urban population. Despite clear subdivision of the urban population, the level of genetic variability was very similar in both analyzed groups. Our findings indicate the occurrence of an advanced process of differentiation of the urban population by microevolution, whereas populations from rural locations displayed very small and mainly insignificant genetic differentiation. Urban local populations, situated near the city borders or close to the natural ecological corridor (banks of the Vistula River), showed higher genetic variability and were less differentiated from populations inhabiting rural sites than from local populations in the city centre. These results provide support for the importance of ecological corridors in preserving the genetic variability of the urban striped field mouse population.     

Genetic and demographic dynamics of small populations of Silene latifolia

Small local populations of Silene alba, a short-lived herbaceous plant, were sampled in 1994 and again in 1999. Sampling included estimates of population size and genetic diversity, as measured at six polymorphic allozyme loci. When averaged across populations, there was very little change between samples (about three generations) in population size, measures of within-population genetic diversity such as number of alleles or expected heterozygosity, or in the apportionment of genetic diversity within and among populations as measured by F(st). However, individual populations changed considerably, both in terms of numbers of individuals and genetic composition. Some populations doubled in size between samples, while others shrank by more than 75%. Similarly, expected heterozygosity and allele number increased by more than two-fold in individual populations and decreased by more than three-fold in others. When population-specific change in number and change in measures of genetic diversity were considered together, significant positive correlations were found between the demographic and genetic variables. It is speculated that some populations were released from the demographic consequences of inbreeding depression by gene flow.     

Genetic structure of chimpanzee populations

Little is known about the history and population structure of our closest living relatives, the chimpanzees, in part because of an extremely poor fossil record. To address this, we report the largest genetic study of the chimpanzees to date, examining 310 microsatellites in 84 common chimpanzees and bonobos. We infer three common chimpanzee populations, which correspond to the previously defined labels of “western,” “central,” and “eastern,” and find little evidence of gene flow between them. There is tentative evidence for structure within western chimpanzees, but we do not detect distinct additional populations. The data also provide historical insights, demonstrating that the western chimpanzee population diverged first, and that the eastern and central populations are more closely related in time.     

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 structure and demographic history of brown trout (Salmo trutta) populations from the southern Balkans

1. The present study was designed to characterize the genetic structure of brown trout ( Salmo trutta ) populations from the southern Balkans and to assess the spread of non-native strains and their introgression into native trout gene pools. We analysed polymorphism at nine microsatellite loci in seven supposedly non-admixed and three stocked brown trout populations.
2. The analyses confirmed the absence of immigration and extraordinarily strong genetic differentiation among the seven non-introgressed populations in parallel with low levels of intrapopulation genetic variability. In contrast, analyses of the stocked populations revealed that the genetic integrity of the local populations had been substantially changed, and the populations must be characterized as hybrid swarms. The pattern of population differentiation observed at microsatellites contrasted to that depicted previously by mtDNA variation. However, the close relationships between populations from the Danube and Axios river systems proposed solely by microsatellites could be explained by palaeogeographic events.
3. Our research showed that most of the populations examined represent unique gene pools, whose existence is critically compromised. Therefore, appropriate management and conservation strategies should be developed urgently in order to protect the subspecific biodiversity and to reverse currently negative trends.     

Genetic demographic analysis of western Ukrainian populations: the marriage structure of populations from the Khmel'nitskii oblast with respect to ethnicity and birthplace

Ukrainians account for 85 and 91% of the populations of the city of Khmel'nitskii and the town of Starokonstantinov (Khmel'nitskii oblast, western Ukraine), respectively, and for 97% of the rural population of the Khmel'nitskii oblast. The proportions of Russians in the urban and rural populations of the Khmel'nitskii oblast are 7-10 and 1%, respectively. Between 1960 and 1995-1998, the proportions of Ukrainians in all populations studied increased and the proportion of interethnic marriages steadily decreased. The marriage association coefficient (K) with respect to ethnicity varied from 0.35 to 0.76 in different years. The highest assortative marriage indices (A') with respect to ethnicity were 75-98 and 71-84% in Ukrainians and Jews, respectively. The migration coefficient was 0.58-0.77. Western Ukrainian populations differ from eastern Ukrainian ones in a steadily decreasing outbreeding component.     

Genetic analysis reveals demographic fragmentation of grizzly bears yielding vulnerably small populations

Ecosystem conservation requires the presence of native carnivores, yet in North America, the distributions of many larger carnivores have contracted. Large carnivores live at low densities and require large areas to thrive at the population level. Therefore, if human-dominated landscapes fragment remaining carnivore populations, small and demographically vulnerable populations may result. Grizzly bear range contraction in the conterminous USA has left four fragmented populations, three of which remain along the Canada-USA border. A tenet of grizzly bear conservation is that the viability of these populations requires demographic linkage (i.e. inter-population movement of both sexes) to Canadian bears. Using individual-based genetic analysis, our results suggest this demographic connection has been severed across their entire range in southern Canada by a highway and associated settlements, limiting female and reducing male movement. Two resulting populations are vulnerably small (< or =100 animals) and one of these is completely isolated. Our results suggest that these trans-border bear populations may be more threatened than previously thought and that conservation efforts must expand to include international connectivity management. They also demonstrate the ability of genetic analysis to detect gender-specific demographic population fragmentation in recently disturbed systems, a traditionally intractable yet increasingly important ecological measurement worldwide.     

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).     

Genetic structure of two urban afro-brazilian populations

A total of 218 individuals living in the Brazilian cities of Porto Alegre (in the South) and Salvador (in the Northeast) were variously studied in relation to nine erythrocyte and four plasma protein systems. The results were compared with previous studies in some of these systems, and estimates of interethnic admixture obtained in subsamples according to morphological appearance. As a whole, Afro-Brazilians from Salvador show 42% of non-African genes, the corresponding figure for Porto Alegre being 59%. The Amerindian contribution to these individuals was estimated as null or negligible. Average heterozygosities are similar to those obtained for African groups, but the gene differentiation coefficient (GST') is small. The phylogenetic tree indicates a closer relationship of Salvador with the African subcluster, as would be expected by the admixture and istorical data. Analyses such as this one are important for the unraveling of the complex networks responsible for the present variability of human populations, and for the dispelling of racist concepts.     

Genetic demographic parameters of the marriage structure of the Yevpatoria population

Records on marriages contracted in the city of Yevpatoria, Ukraine in 1960/1961, 1985, 1993, and 1994/1995 were used to determine some parameters of the city population structure. The coefficients of correlation with respect to the age of marriage in reproductive-age couples contracting marriages in these years were 0.77, 0.81, and 0.80, respectively. Women that contracted marriages at reproductively unfavorable ages (under 20 and over 30 years) in the respective years constituted 28.3, 40.6, and 45.4% of the total sample. The proportions of interethnic marriages in these years were 39.4, 43.9, and 46.6%. The proportion of Slavs decreased from 94 to 91% during 35 years, but the proportion of Ukrainians increased from 23.1 to 26.5%. The proportion of other ethnic groups (Tatars, Armenians, Karaites, Poles, Germans, etc.) increased from 3 to 8.6%. The marriage contingency with respect to ethnicity (K = 0.26 in 1960/1961, K = 0.22 in 1985, and K = 0.28 in 1994/1995) was higher than with respect to education (K = 0.18 in 1985 and K = 0.23 in 1993) or occupation (K = 0.18 in 1960/1961, K = 0.17 in 1985, and K = 0.23 in 1993). The marriage assortativeness with respect to ethnicity was the highest in ethnic minorities (A′ = 55.1%); that with respect to education, in persons who had higher or primary education (A′ = 40.1% and A′ = 78.0%, respectively); and that with respect to occupation, in students, military personnel, and production workers (60.6, 58.7, and 30.9%).     

Genetic demographic parameters of the marriage structure of the Yevpatoria population

Records on marriages contracted in the city of Yevpatoria, Ukraine in 1960/1961, 1985, 1993, and 1994/1995 were used to determine some parameters of the city population structure. The coefficients of correlation with respect to the age of marriage in reproductive-age couples contracting marriages in these years were 0.77, 0.81, and 0.80, respectively. Women that contracted marriages at reproductively unfavorable ages (under 20 and over 30 years) in the respective years constituted 28.3, 40.6, and 45.4% of the total sample. The proportions of interethnic marriages in these years were 39.4, 43.9, and 46.6%. The proportion of Slavs decreased from 94 to 91% during 35 years, but the proportion of Ukrainians increased from 23.1 to 26.5%. The proportion of other ethnic groups (Tatars, Armenians, Karaites, Poles, Germans, etc.) increased from 3 to 8.6%. The marriage contingency with respect to ethnicity (K = 0.26 in 1960/1961, K = 0.22 in 1985, and K = 0.28 in 1994/1995) was higher than with respect to education (K = 0.18 in 1985 and K = 0.23 in 1993) or occupation (K = 0.18 in 1960/1961, K = 0.17 in 1985, and K = 0.23 in 1994/1995). The marriage assortativeness with respect to ethnicity was the highest in ethnic minorities (A' = 55.1%); that with respect to education, in persons who had higher or primary education (A' = 40.1% and A'= 78.0%, respectively); and that with respect to occupation, in students, military personnel, and production workers (60.6, 58.7, and 30.9%).     

Genetic structure of populations of Legionella pneumophila.

The genetic structure of populations of Legionella pneumophila was defined by an analysis of electrophoretically demonstrable allelic variation at structural genes encoding 22 enzymes in 292 isolates from clinical and environmental sources. Nineteen of the loci were polymorphic, and 62 distinctive electrophoretic types (ETs), representing multilocus genotypes, were identified. Principal coordinates and clustering analyses demonstrated that isolates received as L. pneumophila were a heterogeneous array of genotypes that included two previously undescribed species. For 50 ETs of L. pneumophila (strict sense), mean genetic diversity per locus was 0.312, and diversity was equivalent in ETs represented by isolates recovered from clinical sources and those collected from environmental sources. Cluster analysis revealed four major groups or lineages of ETs in L. pneumophila. Genetic diversity among ETs of the same serotype was, on average, 93% of that in the total sample of ETs. Isolates marked by particular patterns of reactivity to a panel of nine monoclonal antibodies were also genetically heterogeneous, mean diversity within patterns being about 75% of the total. Both Pontiac fever and the pneumonic form of legionellosis may be caused by isolates of the same ET. The genetic structure of L. pneumophila is clonal, and many clones apparently are worldwide in distribution. The fact that L. pneumophila is only 60% as variable as Escherichia coli raises the possibility that isolates recovered from clinical cases and man-made environments are a restricted subset of all clones in the species as a whole.     

Genetic and demographic structure of the yakut population: reproduction indices

Genetic and demographic information for the Yakut population living in the Republic of Sakha (Yakutia) is presented. The mean number of children per woman constituted 4.605. Crow's index and its components (Im and If) were 0.483, 0.104, and 0.343, respectively.     

Genetic structure of two Turkish brown trout populations

The genetic structure of two brown trout Salmo trutta populations living in Lake Abant in Bolu and Üzüm River in Antalya was determined by examining 15 enzyme coding loci ( AAT, ADH, LDH, MDH, MEP, GPI, PGM and SOD ) using starch gel electrophoresis. Population specific mobilities were observed for the fixed alleles of LDH-B2, mMEP-2 and SOD-1 loci. Polymorphisms in sAA T-4, GPI-B2 loci were observed within the populations. Average heterozygosity of Abant and Antalya populations was 0.0358 and 0.0224 respectively. For LDH-C which is the post glaciation marker locus, the ancestral allele * 105 was found to be fixed in both of the populations. Nei's genetic distance between the two populations was 0.2507 which is the level of genetic distance often found between different species. This difference seems to be due to the presence of unique alleles in the LDH-B2, mMEP-2 and SOD-1 loci of the Abant population, indicating that the conservation of the Abant population and its heterozygosity is of prime importance.