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 study of Shors in Tashtagolskiĭ district of the Kemerovo region: changes in the marriage migration structure

The changes in the marriage structure with respect to the age at marriage, ethnicity, and spouses' birthplaces during the period of time corresponding to two generations have been analyzed in the rural population of Shors of Tashtagolskii raion of Kemerovo oblast. In general, the Shor population had a high assortative marriage rate with respect to these parameters in the period studied, although there was a temporary tendency towards its decrease. The ages of marriage for both the male and the female Shor populations in the years 2000-2005 were significantly older than in 1940-1945 and 1970-1975. The age-assortative marriage rate was r = = 0.60 in 1940-1945, r = 0.73 in 1970-1975, and r = 0.66 in 2000-2005. The birthplace-assortative marriage rate decreased from 79.63% in 1970-1975 to 70.64% in 2000-2005. The ethnic assortative marriage rate of Shors steadily decreased during the time interval studied; it was 96.92, 89.95, and 80.98% in 1940-1945, 1970-1975, and 2000-2005, respectively, for the total rural population of Tashtagolskii raion.     

Host–parasitoid spatial models: the interplay of demographic stochasticity and dynamics

Host–parasitoid metapopulation models have typically been deterministic models formulated with population numbers as a continuous variable. Spatial heterogeneity in local population abundance is a typical (and often essential) feature of these models and means that, even when average population density is high, some patches have small population sizes. In addition, large temporal population fluctuations are characteristic of many of these models, and this also results in periodically small local population sizes. Whenever population abundances are small, demographic stochasticity can become important in several ways. To investigate this problem, we have reformulated a deterministic, host–parasitoid metapopulation as an integer-based model in which encounters between hosts and parasitoids, and the fecundity of individuals are modelled as stochastic processes. This has a number of important consequences: (1) stochastic fluctuations at small population sizes tend to be amplified by the dynamics to cause massive population variability, i.e. the demographic stochasticity has a destabilizing effect; (2) the spatial patterns of local abundance observed in the deterministic counterpart are largely maintained (although the area of ''spatial chaos'' is extended); (3) at small population sizes, dispersal by discrete individuals leads to a smaller fraction of new patches being colonized, so that parasitoids with small dispersal rates have a greater tendency for extinction and higher dispersal rates have a larger competitive advantage; and (4) competing parasitoids that could coexist in the deterministic model due to spatial segregation cannot now coexist for any combination of parameters.     

Genetic variation and structure of house sparrow populations: is there an island effect?

Population genetic structure and intrapopulation levels of genetic variation have important implications for population dynamics and evolutionary processes. Habitat fragmentation is one of the major threats to biodiversity. It leads to smaller population sizes and reduced gene flow between populations and will thus also affect genetic structure. We use a natural system of island and mainland populations of house sparrows along the coast of Norway to characterize the different population genetic properties of fragmented populations. We genotyped 636 individuals distributed across 14 populations at 15 microsatellite loci. The level of genetic differentiation was estimated using F‐statistics and specially designed Mantel tests were conducted to study the influence of population type (i.e. mainland or island) and geographic distance on the genetic population structure. Furthermore, the effects of population type, population size and latitude on the level of genetic variation within populations were examined. Our results suggest that genetic processes on islands and mainland differed in two important ways. First, the intrapopulation level of genetic variation tended to be lower and the occurrence of population bottlenecks more frequent on islands than the mainland. Second, although the general level of genetic differentiation was low to moderate, it was higher between island populations than between mainland populations. However, differentiation increased in mainland populations somewhat faster with geographical distance. These results suggest that population bottleneck events and genetic drift have been more important in shaping the genetic composition of island populations compared with populations on the mainland. Such knowledge is relevant for a better understanding of evolutionary processes and conservation of threatened populations.     

Has the transition to agriculture reshaped the demographic structure of prehistoric populations? New evidence from the Levant

This paper presents the demographic changes that followed the transition from a hunting-gathering way of life (Natufian) to an agricultural, food-producing economy (Neolithic) in the southern Levant. The study is based on 217 Natufian (10,500-8,300 BC) skeletons and 262 Neolithic (8,300-5,500 BC) skeletons. Age and sex identification were carried out, and life tables were constructed. A five-parameter competing hazard model developed by Siler ([1979] Ecology 60:750-757) was used to smooth life-table data. No indication of increased mortality with the advent of agriculture was noted. On the contrary, both life expectancy at birth (24.6 vs. 25.5 years) and adults' mean age at death (31.2 vs. 32.1 years) increased slightly from the Natufian to the Neolithic period (assuming stationary populations). Yet the transition to agriculture affected males and females differently: mean age at death in the Natufian was higher for adult females compared to adult males, while in the Neolithic, it was the reverse. One interpretation given to the distribution of female ages at death is that with the onset of the Neolithic period, maternal mortality increased as a result of a concomitant increase in fertility. If the adoption of agriculture in the Levant increased the rate of population growth at the beginning of the Neolithic, expectation of life may have increased dramatically.     

Genetic structure of natural populations of the grass endophyte Epichloë festucae in semiarid grasslands

Plants of red fescue (Festuca rubra), a commercially important turf grass, are infected by the fungal endophyte Epichloë festucae in semiarid natural grasslands, known as dehesas, in western Spain. We used amplified fragment length polymorphism (AFLP) markers to analyse the genetic polymorphism existing in two natural populations of Epichloë festucae. Linkage disequilibrium and the presence of clonal lineages indicated that nonrecombinant asexual reproduction predominates in both populations. However, most genetic variation detected was found to occur within populations, with only a moderate amount of genetic differentiation between populations (F_ST: 0.197). Overall, the study suggests that dehesa grasslands are useful reservoirs of Epichloë festucae endophytes, and provides information on population structure which is relevant to design sampling strategies.     

Genetic structure of fragmented populations of a threatened endemic percid of the Rhône river: Zingel asper

Zingel asper is an endemic percid of the Rh?ne basin considered to be critically endangered. This species was continuously distributed throughout the Rh?ne in 1900, but today only occupies 17% of its initial area. In the present study, five microsatellite loci were used to assess the level of genetic variability within and among populations localized in different sub-basins. Contrasting results were obtained for the three main populations from the Rh?ne. A reduced allelic diversity was observed for the two populations displaying the lowest patch sizes (length of the river system occupied); of these, a recent genetic bottleneck was detected for the population showing a particularly low density. However, the third population was characterized by a relatively large spatial extent, high local fish concentrations and an allelic diversity that was twice as high and associated with an equilibrium between mutation and drift. Thus, this population shows an apparently better evolutionary potential for long-term survival. Since 1930, a marked fragmentation of the whole Rh?ne system has appeared, related to the development of dams, and we assume that the significant genetic differentiation detected between the populations could mainly reflect the impact of this fragmentation. The high turnover of the Z. asper populations, and the major role of dispersal in population persistence (highlighted in a recent population dynamics study), indeed suggest that the differentiation observed could mainly have arisen from habitat fragmentation in recent history.     

Genetic and epidemiologic analysis of hereditary diseases of the nervous system in the cities of Volgograd and Volzhskiĭ

A genetic epidemiological study of hereditary diseases of the nervous system (HDNS) was conducted in the cities of Volgograd and Volzhsky for the first time. In total, 1 323 500 individuals were examined including the populations of Volgograd and Volzhsky (1 012 800 and 310 700 persons, respectively). The prevalence of neurological diseases with autosomal dominant (AD), autosomal recessive (AR), and X-linked recessive inheritance was estimated. These data were compared with the estimates previously obtained for different population of the Russian Federation. A decrease was found in general HDNS load in Volgograd and Volzhsky. The compared populations were shown to differ in a contribution of AD, AR, and X-linked recessive diseases into the HDNS load formation. The possible effect of population dynamics factors on the HDNS load structure is discussed.     

Ectoparasites of the zokor Myospalax myospalax (Rodentia) in northern Altaĭ

Following ectoparasites have been recorded on the zokor in the Northern Altay: specific fleas--Ctenophthalmus dilatatus, Rhadinopsylla ioffi, Brachyctenonotus myospalacis; a flea distributed on various rodents; ixodid ticks--Ixodes crenulatus, I. persulcatus; gamasid mites--Hirstionyssus myosplalacis. The C. dilatatus carried hypopi of acaroid mites.     

Genetic structure of the populations migrating from San Luis Potosi and Zacatecas to Nuevo León in Mexico

The Mexicans residing in the Monterrey metropolitan area in Nuevo León, Mexico, were grouped by generation and birthplace [Monterrey Metropolitan Area (MMA), San Luis Potosi (SLP), and Zacatecas (ZAC)] of the four grandparents to determine the extent of genetic variation within this population and the genetic differences, if any, between the natives living in the MMA and the immigrant populations from SLP and ZAC. Nine genetic marker systems were analyzed. The genetic distance analysis indicates that SLP and ZAC are similar to the MMA, irrespective of birthplace and generation. Gene diversity analysis (GST) suggests that more than 96% of the total gene diversity (HT) can be attributed to individual variation within the population. The genetic admixture analysis suggests that the Mexicans of the MMA, SLP, and ZAC, stratified by birthplace and generation, have received a predominantly Spanish contribution (78.5%), followed by a Mexican Indian contribution (21.5%). Similarly, admixture analysis, conducted on the population of Nuevo León and stratified by generation, indicates a substantial contribution from the MMA (64.6%), followed by ZAC (22.1%) and SLP (13.3%). Finally, we demonstrate that there is no nonrandom association of alleles among the genetic marker systems (i.e., no evidence of gametic disequilibrium) despite the Mestizo origin of this population.     

Genetic structure and gene flow in French populations of two Ostrinia taxa: host races or sibling species?

Most models of ecological speciation concern phytophagous insects in which speciation is thought to be driven by host shifts and subsequent adaptations of populations. Despite the ever-increasing number of studies, the current evolutionary status of most models remains incompletely resolved, as estimates of gene flow between taxa remain extremely rare. We studied the population genetics of two taxa of the Ostrinia genus--one feeding mainly on maize and the other on mugwort and hop--occurring in sympatry throughout France. The actual level of divergence of these taxa was unknown because the genetic structure of populations had been investigated over a limited geographical area and the magnitude of gene flow between populations had not been estimated. We used 11 microsatellite markers to investigate the genetic structure of populations throughout France and the extent of gene flow between the two Ostrinia taxa at several sites at which they are sympatric. We observed clear genetic differentiation between most populations collected on the typical respective hosts of each taxon. However, populations displaying intermediate allelic frequencies were found on hop plants in southern France. Individual assignments revealed that this result could be accounted for by the presence of both taxa on the same host. Gene flow, estimated by determining the proportion of hybrids detected, was low: probably<1% per generation, regardless of site. This indicates that the two Ostrinia taxa have reached a high level of genetic divergence and should be considered sibling species rather than host races.     

Genetic and karyotypic structure in the shrews of the Sorex araneus group: are they independent?

The species of the common shrew (Sorex araneus) group are morphologically very similar but exhibit high levels of karyotypic variation. Here we used genetic variation at 10 microsatellite markers in a data set of 212 individuals mostly sampled in the western Alps and composed of five karyotypic taxa (Sorex coronatus, Sorex antinorii and the S. araneus chromosome races Cordon, Bretolet and Vaud) to investigate the concordance between genetic and karyotypic structure. Bayesian analysis confirmed the taxonomic status of the three sampled species since individuals consistently grouped according to their taxonomical status. However, introgression can still be detected between S. antinorii and the race Cordon of S. araneus. This observation is consistent with the expected low karyotypic complexity of hybrids between these two taxa. Geographically based cryptic substructure was discovered within S. antinorii, a pattern consistent with the different postglaciation recolonization routes of this species. Additionally, we detected two genetic groups within S. araneus notwithstanding the presence of three chromosome races. This pattern can be explained by the probable hybrid status of the Bretolet race but also suggests a relatively low impact of chromosomal differences on genetic structure compared to historical factors. Finally, we propose that the current data set (available at http://www.unil.ch/dee/page7010_en.html#1) could be used as a reference by those wanting to identify Sorex individuals sampled in the western Alps.     

Genetic structure of species complex of the spined loach Cobitis auc. (Cypriniformes: Cobitidae) in Severskiĭ Donets river basin

Biochemical, genetic, cytometric and morphological analyses of spined loaches of the middle stream of Severskiy Donetz river revealed 3 bisexual species: Cobitis taenia s.l. (68% of the sample); C. melanoleuca (11%); Sabanejewia aurata (9%) and 2 hybrid forms: triploid C. taenia(2)-sp. (9%) and diploid C. taenia-melanoleuca (3%). Distinctive features of genetic structure of polyploid hybrids C. taenia(2)-sp. as well as taxonomic identity of diploid C. taenia s.l. of Severskiy Donetz river were discussed in regard to the Dnieper population ones.     

Genetic variation and structure in natural and reintroduced populations of the endangered legume,Pyne’s ground plum (Astragalus bibullatus)

Conservation Genetics - Rare species with limited geographic distributions and small census populations are particularly susceptible to genetic drift and inbreeding. Assessing genetic variation...     

Is the impact of environmental noise visible in the dynamics of age-structured populations?

Climate change has ignited lively research into its impact on various population-level processes. The research agenda in ecology says that some of the fluctuations in population size are accountable for by the external noise (e.g. weather) modulating the dynamics of populations. We obeyed the agenda by assuming population growth after a resource-limited Leslie matrix model in an age-structured population. The renewal process was disturbed by superimposing noise on the development of numbers in one or several age groups. We constructed models for iteroparous and semelparous breeders so that, for both categories, the population growth rate was matching. We analysed how the modulated population dynamics correlates with the noise signal with different time-lags. No significant correlations were observed for semelparous breeders, whereas for iteroparous breeders high correlations were frequently observed with time-lags of 71 year or longer. However, the latter occurs under red-coloured noise and for low growth rates when the disturbance is on the youngest age group only. It is laborious to find any clear signs of the (red) noise- and age group-specific fluctuations if the disturbance influences older age groups only. These results cast doubts on the possibility of detecting the signature of external disturbance after it has modulated temporal fluctuations in age-structured populations.     

Bryophyte diaspore bank: a genetic memory? Genetic structure and genetic diversity of surface populations and diaspore bank in the liverwort Mannia fragrans (Aytoniaceae)

Propagule banks are assumed to be able to store considerable genetic variability. Bryophyte populations are expected to rely more heavily on stored propagules than those of seed plants due to the vulnerability of the haploid gametophyte. This reliance has important implications for the genetic structure and evolutionary potential of surface populations. A liverwort, Mannia fragrans, was used to test whether the bryophyte diaspore bank functions as a "genetic memory." If a diaspore bank is capable of conserving genetic variability over generations, the levels of genetic diversity in the soil are expected to be similar or higher than at the surface. Surface and diaspore bank constituents of two populations of M. fragrans were investigated. Genetic structure and diversity measured as unbiased heterozygosity were analyzed using three ISSR markers. Similar genetic diversities were found in the soil (H(s) = 0.067) and at the surface (H(s)= 0.082). However, more haplotypes and specific haplotype lineages were present in soil samples. The results suggest that the bryophyte diaspore bank has an important role in accumulating genetic variability over generations and seasons. It is postulated that the role of the diaspore bank as a "genetic memory" is especially important in species of temporarily available habitats that have long-lived spores and genetically variable populations.     

Effect of glycerol–water binary mixtures on the structure and dynamics of protein solutions

We have performed 20?ns of fully atomistic molecular dynamics simulations of Hen Egg-White Lysozyme in 0, 10, 20, 30, and 100% by weight of glycerol in water to better understand the microscopic physics behind the bioprotection offered by glycerol to naturally occuring biological systems. The solvent exposure of protein surface residues changes when glycerol is introduced. The dynamic behavior of the protein, as quantified by the incoherent intermediate scattering function, shows a nonmonotonic dependence on glycerol content. The fluctuations of the protein residues with respect to each other were found to be similar in all water-containing solvents, but different from the pure glycerol case. The increase in the number of protein–glycerol hydrogen bonds in glycerol–water binary mixtures explains the slowing down of protein dynamics as the glycerol content increases. We also explored the dynamic behavior of the hydration layer. We show that the short length scale dynamics of this layer are insensitive to glycerol concentration. However, the long length scale behavior shows a significant dependence on glycerol content. We also provide insights into the behavior of bound and mobile water molecules.     

Hepatitis B markers in southern Altaĭ inhabitants of the village of Mendur-Sokkon (the Republic of Altaĭ). HBsAg subtyping in hepatitis B virus isolates with monoclonal antibodies

Blood samples taken from 231 native inhabitants of the village of Mendur-Sokkon located in the Republic of Altai (South-Western Siberia, Russia) were tested for the presence of virus hepatitis B (HBV) markers. 31 samples (13.4%) were found to contain HBsAg, 111 samples (48.05%) were found to contain total anti-HBc antibodies, 123 samples (53.24%) were found to contain anti-HBs antibodies and 15 blood samples (6.49%), anti-HBc antibodies without anti-HBs antibodies and HBsAg. The age-dependent distribution of the occurrence of HBV markers among the aboriginal population of the South Altal remained unchanged (69.9 +/- 7.9%) for the last 50 years. The vertical and horizontal routes of HBV transmissions were noted. The data obtained in this study are indicative of a highly endemic character of HBV of the territory of Mendur-Sokkon. HBsAg-positive blood samples were taken for HBsAg subtyping with the use of a panel of monoclonal antibodies. Two subtypes of HBsAg were detected: ayw1-2 and ayw3varB with the occurrence of 92.6% and 7.4%, i.e. distributed in the ratio 25/2.     

Molecular dynamics simulation of the reciprocal fused LiF–KBr mixture: local structure and self-diffusion coefficients

This paper describes the molecular dynamics simulation of the reciprocal fused LiF–KBr mixture, which is located above the critical mixing point, in the temperature range 1280–1450 K. The first coordination sphere is found to form as follows: a smaller ion is formed around a smaller counter-ion, and a larger ion is formed around a larger counter-ion. The calculated concentration dependence of the self-diffusion coefficients and the radial distribution functions of all ion pairs indicate that the degree of association of the Li–F pair increases as the lithium fluoride fraction in the mixture decreases.     

The effects of gene flow and population isolation on the genetic structure of␣reintroduced wild turkey populations: Are genetic signatures of source populations retained?

To counter losses of genetic diversity in reintroduced populations, species sometimes are reintroduced into networks of populations with the potential to exchange individuals. In reintroduced populations connected by gene flow, patterns of genetic structure initiated by the founding event may become obscured, and populations may eventually follow an isolation-by-distance model of genetic differentiation. Taking advantage of well-documented reintroduction histories of wild turkey populations in Indiana, we assessed the degree to which gene flow among reintroduced populations has obscured genetic signatures left by the founding events. Using a suite of nuclear microsatellite loci and sequence data from the mitochondrial control region, we characterized the level of genetic diversity and degree of genetic structure within and among: (1) reintroduced populations in isolated northern Indiana Fish and Wildlife Areas, (2) reintroduced populations in southern Indiana Fish and Wildlife Areas, where the distribution of populations is more continuous, and (3) source populations used for these reintroductions. We also utilized individual-based assignment tests to determine the relative contribution of source populations to the current distribution of alleles in reintroduced populations. Our results indicate that wild turkey reintroductions in Indiana have left distinct genetic signatures on populations that are detectable even after several decades. Although we found some case-specific evidence for gene flow, particularly in regions where populations are in close proximity, our data indicate on overall paucity of gene flow at a regional scale. Such post-reintroduction genetic monitoring has immediate implications for the design of optimal strategies to reintroduce wildlife for conservation and management.