The russian gene pool: the gene geography of Alu insertions (ACE, APOA1, B65, PV92, TPA25)

For the first time, an analysis of five Alu insertion loci (ACE, APOA1, B65, PV92, TPA25) has been carried out in 10 Russian populations (1088 individuals) covering the whole historical area of the Russian ethnos. Depending on the locus, Russian populations exhibit similarity to their Western (European populations) or Eastern (populations of the Ural region) neighbors. Considering the frequencies of the studied Alu-insertions, the Russian gene pool exhibits low variation: average interpopulation variation (d) was 0.007, whereas on classical markers, mtDNA and Y chromosome, heterogeneity of the Russian gene pool is essentially higher (0.013, 0.033, 0.142, respectively). Therefore, on the intra-ethnic level, this set of five Alu insertions has low variation. However, a clear pattern was obtained in inter-ethnic comparison of 13 East European ethnic groups, which formed three clusters in accordance with their historical and geographical position: East Slavic, Caucasian and South Ural clusters. The obtained data confirm the efficiency of using Alu insertions for studying genetic differentiation and gene pool history of East European populations.     

Pathogen-Driven Outbreaks in Forest Defoliators Revisited: Building Models from Experimental Data

Models of outbreaks in forest-defoliating insects are typically built from a priori considerations and tested only with long time series of abundances. We instead present a model built from experimental data on the gypsy moth and its nuclear polyhedrosis virus, which has been extensively tested with epidemic data. These data have identified key details of the gypsy moth-virus interaction that are missing from earlier models, including seasonality in host reproduction, delays between host infection and death, and heterogeneity among hosts in their susceptibility to the virus. Allowing for these details produces models in which annual epidemics are followed by bouts of reproduction among surviving hosts and leads to quite different conclusions than earlier models. First, these models suggest that pathogen-driven outbreaks in forest defoliators occur partly because newly hatched insect larvae have higher average susceptibility than do older larvae. Second, the models show that a combination of seasonality and delays between infection and death can lead to unstable cycles in the absence of a stabilizing mechanism; these cycles, however, are stabilized by the levels of heterogeneity in susceptibility that we have observed in our experimental data. Moreover, our experimental estimates of virus transmission rates and levels of heterogeneity in susceptibility in gypsy moth populations give model dynamics that closely approximate the dynamics of real gypsy moth populations. Although we built our models from data for gypsy moth, our models are, nevertheless, quite general. Our conclusions are therefore likely to be true, not just for other defoliator-pathogen interactions, but for many host-pathogen interactions in which seasonality plays an important role. Our models thus give qualitative insight into the dynamics of host-pathogen interactions, while providing a quantitative interpretation of our gypsy moth-virus data.     

Population distribution of the methionine allele at the PRNP codon 129 polymorphism in Europe and the Middle East

Methionine homozygosity at codon 129 of the prion protein gene is a risk factor for Creutzfeldt-Jakob disease. Knowledge of M129V polymorphism in normal populations may contribute to a better understanding of prion diseases. M129V polymorphism was studied in 2201 normal subjects, originating from 15 populations from Europe and the Middle East. Mean heterozygosity in these populations is 38.9%, and there is some significant geographic heterogeneity between them. A comparison of M129 allele frequencies in these 15 populations to those already published for 8 European countries plus Turkey shows significant correlations with both latitude (r = -0.77) and longitude (r = 0.69). The geographic map of methionine allele frequencies indicates an east-west gradient of decreasing methionine allele values from the Middle East to Western Europe.     

Microsatellite diversity among the primitive tribes of India

The present study was undertaken to determine the extent of diversity at 12 microsatellite short tandem repeat (STR) loci in seven primitive tribal populations of India with diverse linguistic and geographic backgrounds. DNA samples of 160 unrelated individuals were analyzed for 12 STR loci by multiplex polymerase chain reaction (PCR). Gene diversity analysis suggested that the average heterozygosity was uniformly high ( >0.7) in these groups and varied from 0.705 to 0.794. The Hardy-Weinberg equilibrium analysis revealed that these populations were in genetic equilibrium at almost all the loci. The overall G(ST) value was high (G(ST) = 0.051; range between 0.026 and 0.098 among the loci), reflecting the degree of differentiation/heterogeneity of seven populations studied for these loci. The cluster analysis and multidimensional scaling of genetic distances reveal two broad clusters of populations, besides Moolu Kurumba maintaining their distinct genetic identity vis-à-vis other populations. The genetic affinity for the three tribes of the Indo-European family could be explained based on geography and Language but not for the four Dravidian tribes as reflected by the NJT and MDS plots. For the overall data, the insignificant MANTEL correlations between genetic, linguistic and geographic distances suggest that the genetic variation among these tribes is not patterned along geographic and/or linguistic lines.     

Host heterogeneity in susceptibility and disease dynamics: tests of a mathematical model

Most mathematical models of disease assume that transmission is linearly dependent on the densities of host and pathogen. Recent data for animal diseases, however, have cast doubt on this assumption, without assessing the usefulness of alternative models. In this article, we use a combination of laboratory dose-response experiments, field transmission experiments, and observations of naturally occurring populations to show that virus transmission in gypsy moths is a nonlinear function of virus density, apparently because of heterogeneity among individual gypsy moth larvae in their susceptibility to the virus. Dose-response experiments showed that larvae from a laboratory colony of gypsy moths are substantially less heterogeneous in their susceptibility to the virus than are larvae from feral populations, and field experiments showed that there is a more strongly nonlinear relationship between transmission and virus density for feral larvae than for lab larvae. This nonlinearity in transmission changes the dynamics of the virus in natural populations so that a model incorporating host heterogeneity in susceptibility to the virus gives a much better fit to data on virus dynamics from large-scale field plots than does a classical model that ignores host heterogeneity. Our results suggest that heterogeneity among individuals has important effects on the dynamics of disease in insects at several spatial and temporal scales and that heterogeneity in susceptibility may be of general importance in the ecology of disease.     

Modeled global invasive potential of Asian gypsy moths, Lymantria dispar

Asian populations of gypsy moths, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), remain poorly characterized – indeed, they are not presently accorded any formal taxonomic status within the broader species. Their ecology is similarly largely uncharacterized in the literature, except by assumption that it will resemble that of European populations. We developed ecological niche models specific to Asian populations of the species, which can in turn be used to identify a potential geographic distributional area for the species. We demonstrated statistically significant predictivity of distributional patterns within the East Asian range of these populations; projecting the Asian ecological niche model to Europe, correspondence with European distributions was generally good, although some differences may exist; projecting the ecological niche model globally, we characterized a likely potential invasive distribution of this set of populations across the temperate zone of both Northern and Southern Hemisphere.     

STR Polymorphism in Indigenous Daghestan Populations

Genomic diversity of 21 STR loci has been studied in six ethnic populations of Daghestan (the Caucasus), namely, Avars, Dargins, Kubachians, Lezgins, Kumiks, and Nogais, and the results have been compared with these data for European, African, and East Asian ethnic groups. Daghestan is unique in its ethnic diversity, which is the greatest in the Caucasus: 26 out of approximately 50 autochthonous ethnic groups of the Caucasus live there. The genetic origin of this wide ethnic diversity of Daghestan and the Caucasus as a whole is still obscure. The genetic heterogeneity of Daghestan populations has been found to be lower than that of most other populations in the world. This is explained by a prolonged isolation and gene drift in their demographic history. Generalized genetic distances between ethnic groups calculated for the whole set of loci studied allow differentiating Asian populations from African ones, with European populations occupying intermediate positions. All Daghestan ethnic populations form a distinct common group together with some European populations (Finnish, Polish, and French). Nogais are genetically close to Southeast Asian populations. The genetic closeness and the apparently equal genetic diversity of Daghestan and European populations suggest that the ethnic differentiation of the ancestral populations of Daghestan and European ethnic groups occurred in the earliest populations of modern humans.     

STR polymorphism in populations of indigenous Daghestan ethnic groups

Genomic diversity of 21 STR loci has been studied in six ethnic populations of Daghestan (the Caucasus), namely, Avars, Dargins, Kubachians, Lezgins, and Nogais, and the results have been compared with these data for European, African, and East Asian ethnic groups. Daghestan is unique in its ethnic diversity, which is the greatest in the Caucasus: 26 out of approximately 50 autochthonous ethnic groups of the Caucasus live there. The genetic origin of this wide ethnic diversity of Daghestan and the Caucasus as a whole is still obscure. The genetic heterogeneity of Daghestan populations has been found to be lower than that of most other populations in the world. This is explained by a prolonged isolation and gene drift in their demographic history. Generalized genetic distances between ethnic groups calculated for the whole set of loci studied allow differentiating Asian populations from African ones, with European populations occupying intermediate positions. All Daghestan ethnic populations form a distinct common group together with some European populations (Finnish, Polish, and French). Nogais are genetically close to Southeast Asian populations. The genetic closeness and the apparently equal genetic diversity of Daghestan and European populations suggest that the ethnic differentiation of the ancestral populations of Daghestan and European ethnic groups occurred in the earliest populations of modern humans.     

Surprising diversity in the Pannonian populations of Marsh Fritillary (Euphydryas aurinia,Lepidoptera: Nymphalidae): Morphometric and molecular aspects

Since genetic variation is the basis of evolutionary potential of a species, its structure needs to be understood. Thus, the aim of this study was to analyze and contrast the structure of genetic and phenotypic variation in the Euphydryas aurinia populations of southeastern central Europe. Genetic variation was studied by two types of molecular genetic markers: mtDNA COI sequences and allozymes. As the great hiatus in the European distribution of E. aurinia is located in the central part of the Carpathian Basin, we expected that the populations East and West to this gap would be highly differentiated. Populations of Central Transdanubia actually represent the easternmost margin of the West European distribution of E. aurinia. In view of the peripheral position of these populations, we supposed to find some genetic sign of local adaptation, as a consequence of diversifying selection and an increased level of fluctuating asymmetry as a result of environmental stress. The analyses of the molecular genetic markers revealed a basic East–West differentiation among the populations of southeastern central Europe which was further structured in the western part of the study area. The results suggested that the genetic differentiation between the two western regions is probably the consequence of diversifying selection. The pattern of phenotypic differentiation among the western populations, however, was different. A geographic cline was revealed (decreasing wing size) toward the eastern margin of the distribution in parallel with increasing fluctuating asymmetry. The conservation inferences of the results are considered.     

Genetic split between coastal and continental populations of gypsy moth separated by Dinaric Alps

The gypsy moth, a polyphagous herbivore species, infests mainly deciduous trees in the northern hemisphere, being invasive in North America. In Croatia, gypsy moth is infesting both continental and coastal forests, with the Dinaric Alps posing a physical migratory barrier between two regions. During outbreaks, caterpillars cause severe damages in both regions, though with different outbreak dynamics, which suggests genetic differences between populations. Representative populations from these two regions were screened by sequencing a region of the mitochondrial COI gene. Ninety‐nine sequences resulted in seventeen haplotypes, and analyses revealed a significant genetic differentiation between coastal and continental populations, quite likely attributed to geographic isolation and post‐glacial history. This differentiation arises from significantly higher genetic variability in Mediterranean population, indicating their higher adaptability, an intriguing fact in case of possible northward range shift of gypsy moth.     

Underestimated mitochondrial diversity in gypsy moth Lymantria dispar from Asia

相似文献   

Genetic heterogeneity among three Adi tribes of Arunachal Pradesh, India

We studied the distribution of ABO blood groups among three little known subtribes of the Adi tribe, namely, the Panggi, Komkar, and Padam, of the East and Upper Siang districts of Arunachal Pradesh, India. Blood group O was the predominant group in the Komkar and Padam, whereas group A was the predominant group in the Panggi. Blood group AB was found to be the least frequent group in all three studied populations. The populations showed significant differences in blood groups A (43% in Panggi, 23% in Komkar, and 18% in Padam) and O (33% in Panggi, 54% in Komkar, and 61% in Padam). The chi-square test indicated significant deviation from Hardy-Weinberg equilibrium, suggesting high heterogeneity among the tribes.     

Population differentiation within and among Asian elephant (Elephas maximus) populations in southern India

Southern India, one of the last strongholds of the endangered Asian elephant (Elephas maximus), harbours about one-fifth of the global population. We present here the first population genetic study of free-ranging Asian elephants, examining within- and among-population differentiation by analysing mitochondrial DNA (mtDNA) and nuclear microsatellite DNA differentiation across the Nilgiris-Eastern Ghats, Anamalai, and Periyar elephant reserves of southern India. Low mtDNA diversity and 'normal' microsatellite diversity were observed. Surprisingly, the Nilgiri population, which is the world's single largest Asian elephant population, had only one mtDNA haplotype and lower microsatellite diversity than the two other smaller populations examined. There was almost no mtDNA or microsatellite differentiation among localities within the Nilgiris, an area of about 15,000 km2. This suggests extensive gene flow in the past, which is compatible with the home ranges of several hundred square kilometres of elephants in southern India. Conversely, the Nilgiri population is genetically distinct at both mitochondrial and microsatellite markers from the two more southerly populations, Anamalai and Periyar, which in turn are not genetically differentiated from each other. The more southerly populations are separated from the Nilgiris by only a 40-km-wide stretch across a gap in the Western Ghats mountain range. These results variably indicate the importance of population bottlenecks, social organization, and biogeographic barriers in shaping the distribution of genetic variation among Asian elephant populations in southern India.     

Genetic diversity in inter‐simple sequence repeat profiles across natural populations of Indian pomegranate (Punica granatum L.)

Pomegranate (Punica granatum L.), in the monogeneric family Punicaceae, is found in Iran, Afghanistan, India and Mediterranean countries. Iran is considered to be its primary centre of origin. In India, pomegranate occurs naturally only in the Western Himalayan regions of Jammu and Kashmir, Himachal Pradesh and Uttarakhand States. However, there is no information about genetic variation in wild pomegranate at population level. In this paper, we describe genetic diversity across natural populations of Indian pomegranate based on inter‐simple sequence repeat (ISSR) markers. Forty‐nine accessions representing eight populations from two regions were analysed using ISSR. Seventeen ISSR primers resulted in 268 polymorphic bands, with 87.01% polymorphism throughout the accessions. Pair‐wise population genetic distances ranged from 0.05 to 0.45, with a mean of 0.25 between populations. amova and Nei’s genetic diversity analyses revealed higher genetic variation within populations than among populations. A higher genetic differentiation (G_ST) was observed between the spatially distant populations, indicating a low level of genetic exchange (Nm) among these populations. However, clustering of populations was not in accordance with their geographical affiliations in the tree. The results indicate that the ISSR method is sufficiently informative and powerful to assess genetic variability in pomegranate, and that patterns of genetic variability observed among populations of wild pomegranate from the Western Himalaya differ. Estimation of genetic variation reported here provides a significant insight for in situ conservation and exploitation of genetic resources for this economically important species as potential breeding material.     

Russian ethnic history inferred from mitochondrial DNA diversity

With the aim of gaining insight into the genetic history of the Russians, we have studied mitochondrial DNA diversity among a number of modern Russian populations. Polymorphisms in mtDNA markers (HVS-I and restriction sites of the coding region) of populations from 14 regions within present-day European Russia were investigated. Based on analysis of the mitochondrial gene pool geographic structure, we have identified three different elements in it and a vast "intermediate" zone between them. The analysis of the genetic distances from these elements to the European ethnic groups revealed the main causes of the Russian mitochondrial gene pool differentiation. The investigation of this pattern in historic perspective showed that the structure of the mitochondrial gene pool of the present-day Russians largely conforms to the tribal structure of the medieval Slavs who laid the foundation of modern Russians. Our results indicate that the formation of the genetic diversity currently observed among Russians can be traced to the second half of the first millennium A.D., the time of the colonization of the East European Plain by the Slavic tribes. Patterns of diversity are explained by both the impact of the native population of the East European Plain and by genetic differences among the early Slavs.     

Joint effects of natural selection and recombination on gene flow between Drosophila ananassae populations

We estimated DNA sequence variation in a 5.7-kb fragment of the furrowed (fw) gene region within and between four populations of Drosophila ananassae; fw is located in a chromosomal region of very low recombination. We analyzed gene flow between these four populations along a latitudinal transect on the Indian subcontinent: two populations from southern, subtropical areas (Hyderabad, India, and Sri Lanka) and two from more temperate zones in the north (Nepal and Burma). Furthermore, we compared the pattern of differentiation at fw with published data from Om(1D), a gene located in a region of normal recombination. While differentiation at Om(1D) shows an isolation-by-distance effect, at fw the pattern of differentiation is quite different such that the frequencies of single nucleotide polymorphisms are homogenized over extended geographic regions (i.e., among the two populations of the northern species range from Burma and Nepal as well as among the two southern populations from India and Sri Lanka), but strongly differentiated between the northern and southern populations. To examine these differences in the patterns of variation and differentiation between the Om(1D) and fw gene regions, we determine the critical values of our previously proposed test of the background selection hypothesis (henceforth called F(ST) test). Using these results, we show that the pattern of differentiation at fw may be inconsistent with the background selection model. The data depart from this model in a direction that is compatible with the occurrence of recent selective sweeps in the northern as well as southern populations.     

Size at birth and some sociodemographic factors in gypsies in Hungary

In 10,108 babies born to gypsy parents, birth weight, birth length and gestational age are compared with a national reference sample, taking into account maternal education, age, and birth interval. The gypsy babies tend consistently to be smaller, and this difference is attributable to the circumstances in which the gypsies live as well as the poorer maternal education. There appears to be a vicious circle--poor hygiene and living conditions adversely affect birth size, which in turn puts the child at a disadvantage in terms of survival, health and development.     

Low levels of genetic divergence across geographically and linguistically diverse populations from India

Ongoing modernization in India has elevated the prevalence of many complex genetic diseases associated with a western lifestyle and diet to near-epidemic proportions. However, although India comprises more than one sixth of the world's human population, it has largely been omitted from genomic surveys that provide the backdrop for association studies of genetic disease. Here, by genotyping India-born individuals sampled in the United States, we carry out an extensive study of Indian genetic variation. We analyze 1,200 genome-wide polymorphisms in 432 individuals from 15 Indian populations. We find that populations from India, and populations from South Asia more generally, constitute one of the major human subgroups with increased similarity of genetic ancestry. However, only a relatively small amount of genetic differentiation exists among the Indian populations. Although caution is warranted due to the fact that United States–sampled Indian populations do not represent a random sample from India, these results suggest that the frequencies of many genetic variants are distinctive in India compared to other parts of the world and that the effects of population heterogeneity on the production of false positives in association studies may be smaller in Indians (and particularly in Indian-Americans) than might be expected for such a geographically and linguistically diverse subset of the human population.     

Allozyme Diversity and Interspecific Differentiation o the Two Diploid Bromegrass Species, Bromus tectorum L. and B. sterilis L (Poaceae)

Abstract: Genetic diversity among 50 accessions of Bromus tectorum and 43 of B. sterilis from different sites of their Eurasian ranges has been studied by electrophoretic analysis of ten enzymes encoded by 18 loci. The two species proved clearly differentiated by alternate allozymes at seven isozymes. Populations of both taxa showed differentiation into eleven (B. tectorum ) and six (B. sterilis ) multilocus allozyme lineages (MLALs). The extent of interspecific allozyme divergence estimated by Manhattan distance exceeded more than three times intraspecific differentiation between the multilocus lineages. Only two MLALs in each species have wide geographical distribution from the Near East to Europe. Other MLAL5 were found each for only one or two populations and were region-specific. Most geographically marginal European populations had widespread MLALs.     

Phylogeografic analysis of mitochondrial DNA Nogays: the high level of mixture of maternal lineages from Eastern and Western Eurasia

Analysis of markers mtDNA in a population of Nogays (n = 206), living on Nothern Caucasus and speaking on language of Turkic branch of the Altaic linguistic family, has shown, that the level of their genetic differentiation is high (H = 0.99). Among the found haplotypes there is all the basic Western Eurasian haplogroups, most often of which are clusters H (22%) and U (21%), however, the percentage of the lineages specific only for populations of East Eurasia (40%) is highest. In a population of Nogays there are also variants mtDNA, belonging to haplogroup M1, characteristic for North East Africa, and gaplogroup U2, typical for populations of India. This testifies about presence in a gene pool of Nogays people of components of a various parentage.