Distribution of a deletion-insertion polymorphism in intergenic region V of mitochondrial DNA among the aboriginal population of Tuva

Mitochondrial DNA region V deletion-insertion polymorphism was examined in three Tuvinian populations inhabiting western, northeastern, and southeastern parts of the republic. The 9-bp deletion was characterized by nonrandom distribution across the Tuva territory: its frequency in the western population (13.37%) was statistically significantly higher than that in the northeastern (4.62%), and southeastern populations, as well as in Mongols, who are territorially and ethnically close to Tuvinians. The insertion mutation in the region V was detected with a frequency of about 3% in two out of the three populations tested.     

Structure of the gene pool of ethnic groups from the Altai-Sayan region from data on mitochondrial polymorphism]

Using the data on mitochondrial DNA (mtDNA) polymorphism, genetic structures of the four Turkic-speaking ethnic groups of Altai-Sayan highlands, Southern Altaians (Altai-Kizhi), Khakassians, Shorians, and Sojots, were described. Mitochondrial gene pools of the populations examined were characterized by different ratios between Mongoloid (M*, C, D, E, G, A, B, and F) and Caucasoid (H, U, T, J, and K) mtDNA lineages. All the populations studied had a strongly pronounced Mongoloid component, the frequency of which was 88.2% in Sojots, 75.9% in Khakassians, 67.4% in Altaians, and 64.3% in Shorians. Maximum frequency of the Caucasoid component (35.7%) was observed in Shorians. Phylogenetic and statistical analyses of the mtDNA group frequency distribution patterns in the gene pools of the ethnic populations of Altai-Sayan highlands and the adjacent territories showed that the populations of the region fell into three groups. The first group included Khakassians, Tuvinians and Altaians, the second group consisted of Sojots, Buryats, and Mongols, while the third group was composed of Uigurs, Kazakhs, and Kyrgyzes. The isolated position of Shorians among the populations examined can be explained by their different anthropological composition and their presumptive relatedness to Finno-Ugric populations of Siberia.     

Genogenography of the aboriginal population of Marii El (from data on immunobiochemical polymorphism)

The geographic distribution of the frequencies of genes related to the immunological and biochemical polymorphism was studied in the Maris, who are the indigenous population of the Marii El Republic. Data on the frequencies of 33 alleles of 10 loci (ABO, TF, GC, PI, HP, AHS, F13B, ACP1, PGM1, and GLO1) in five raions (districts) of Marii El were obtained. Computer interpolation maps were constructed for all alleles. The maps allows to predict the distribution of the alleles throughout Marii El. A map of the reliability of the cartographic prediction was drawn. For the first time, the reliability of predicted gene frequencies were taken into account in constructing and interpreting the maps of gene frequencies. For the entire set of the studied genes, parameters of heterozygosity (HS) and gene diversity (GST) were estimated. Cartographic correlation analysis was performed to reveal the relationship between gene frequencies and geographic coordinates. It was found that 42% of the studied genes predominantly correlated with latitude and 9% with longitude. It was assumed that the genetic structure of Mari populations had been mainly determined by latitude-related factors. A map of Nei's genetic distances between the overall Mari gene pool and the local populations revealed a central core, which was close to the "average Mari" gene pool, and a periphery, which was genetically distant from it. Suggestions on the microevolution of the Mari gene pool were advanced. Maps of the genes with the most characteristic genetic relief (ABO*B, ACP*A, TF*D, GC*1F, PI*M2, HP*1F, and F13B*3) are shown. These maps exhibit a high correlation with the maps of principal components.     

"Synthetic" maps of the Mari gene pool (from immunobiochemical polymorphism data)]

Models of geographic distribution of 33 alleles of 10 loci (AB0, TF, GC, PI, HP, AHS, F13B, ACP1, PGM1, GLO1) in the indigenous population of five raions (districts) of Marii El Republic were analyzed by cartographic statistical methods. Based on 33 maps for individual alleles, synthetic maps were constructed; they reflected the general characteristics of the spatial variability of the Mari gene pool. A map of reliability of the synthetic maps was also obtained. This study was the first to use estimates of the reliability of the gene-geographic prognosis for constructing and interpreting the maps of principal components. Synthetic maps of principal components reveal the geography of the main factors that determine the genetic diversity of the Maris. In the map of the first principal component (accounting for 25.5% of the total variation of the Mari gene pool), isolines clearly ran in the latitudinal direction; i.e., the variability exhibited a north-south gradient. The direction of changes reflects the characteristic features of the microevolution of the Mari gene pool, because it differs from the direction of the principal components of in the total Ural gene pool. The second principal component (24.3% of variation) also exhibited a latitudinal gradient in the western part of Marii El. In the eastern part of the republic, isolines drastically change their direction and display a marked west-east gradient. This longitudinal orientation of principal components is characteristic of the Maris in the synthetic maps of the Ural region. Contributions of individual genes in the variation of principal components were analyzed. In proceeding from the geographic space to the space of principal components, it was found that Highland Maris are separated from Meadow Maris not only geographically, but also genetically.     

Genetic diversity of Besermyans inferred from mitochondrial DNA polymorphism

The first data are presented on mtDNA diversity in Besermyans, the Finno-Ugric ethnic group related to Udmurts. An analysis of mtDNA polymorphism showed that Besermyans stood out from the other populations of Volga-Ural region due to the presence of a large proportion of the Mongoloid component. The sample of Besermyans contained East Eurasian haplotypes not detected in ethnic populations of the Volga region and Cisurals, while they were detected in South Siberia, mostly among Turkic-speaking populations. An analysis of the genetic distances between Besermyans and the neighboring ethnic groups showed that Besermyans were distant from other populations of Volga-Ural region and close to Turkic-speaking populations of South Siberia. Thus, the data obtained favor the suggestion on the mixed Udmurto-Turkic origin of Besermyans.     

Inferring population parameters from single-feature polymorphism data

This article is concerned with a statistical modeling procedure to call single-feature polymorphisms from microarray experiments. We use this new type of polymorphism data to estimate the mutation and recombination parameters in a population. The mutation parameter can be estimated via the number of single-feature polymorphisms called in the sample. For the recombination parameter, a two-feature sampling distribution is derived in a way analogous to that for the two-locus sampling distribution with SNP data. The approximate-likelihood approach using the two-feature sampling distribution is examined and found to work well. A coalescent simulation study is used to investigate the accuracy and robustness of our method. Our approach allows the utilization of single-feature polymorphism data for inference in population genetics.     

Decrypting the mitochondrial gene pool of modern Panamanians

The Isthmus of Panama--the narrow neck of land connecting the northern and southern American landmasses--was an obligatory corridor for the Paleo-Indians as they moved into South America. Archaeological evidence suggests an unbroken link between modern natives and their Paleo-Indian ancestors in some areas of Panama, even if the surviving indigenous groups account for only 12.3% of the total population. To evaluate if modern Panamanians have retained a larger fraction of the native pre-Columbian gene pool in their maternally-inherited mitochondrial genome, DNA samples and historical records were collected from more than 1500 volunteer participants living in the nine provinces and four indigenous territories of the Republic. Due to recent gene-flow, we detected ~14% African mitochondrial lineages, confirming the demographic impact of the Atlantic slave trade and subsequent African immigration into Panama from Caribbean islands, and a small European (~2%) component, indicating only a minor influence of colonialism on the maternal side. The majority (~83%) of Panamanian mtDNAs clustered into native pan-American lineages, mostly represented by haplogroup A2 (51%). These findings reveal an overwhelming native maternal legacy in today's Panama, which is in contrast with the overall concept of personal identity shared by many Panamanians. Moreover, the A2 sub-clades A2ad and A2af (with the previously named 6 bp Huetar deletion), when analyzed at the maximum level of resolution (26 entire mitochondrial genomes), confirm the major role of the Pacific coastal path in the peopling of North, Central and South America, and testify to the antiquity of native mitochondrial genomes in Panama.     

Interpreting ecological diversity indices applied to terminal restriction fragment length polymorphism data: insights from simulated microbial communities

Ecological diversity indices are frequently applied to molecular profiling methods, such as terminal restriction fragment length polymorphism (T-RFLP), in order to compare diversity among microbial communities. We performed simulations to determine whether diversity indices calculated from T-RFLP profiles could reflect the true diversity of the underlying communities despite potential analytical artifacts. These include multiple taxa generating the same terminal restriction fragment (TRF) and rare TRFs being excluded by a relative abundance (fluorescence) threshold. True community diversity was simulated using the lognormal species abundance distribution. Simulated T-RFLP profiles were generated by assigning each species a TRF size based on an empirical or modeled TRF size distribution. With a typical threshold (1%), the only consistently useful relationship was between Smith and Wilson evenness applied to T-RFLP data (TRF-E(var)) and true Shannon diversity (H'), with correlations between 0.71 and 0.81. TRF-H' and true H' were well correlated in the simulations using the lowest number of species, but this correlation declined substantially in simulations using greater numbers of species, to the point where TRF-H' cannot be considered a useful statistic. The relationships between TRF diversity indices and true indices were sensitive to the relative abundance threshold, with greatly improved correlations observed using a 0.1% threshold, which was investigated for comparative purposes but is not possible to consistently achieve with current technology. In general, the use of diversity indices on T-RFLP data provides inaccurate estimates of true diversity in microbial communities (with the possible exception of TRF-E(var)). We suggest that, where significant differences in T-RFLP diversity indices were found in previous work, these should be reinterpreted as a reflection of differences in community composition rather than a true difference in community diversity.     

Structure of the gene pool of eastern Ukrainians from Y-chromosome haplogroups

Y chromosomes from representative sample of Eastern Ukrainians (94 individuals) were analyzed for composition and frequencies of haplogroups, defined by 11 biallelic loci located in non-recombining part of the chromosome (SRY1532, YAP, 92R7, DYF155S2, 12f2, Tat, M9, M17, M25, M89, and M56). In the Ukrainian gene, pool six haplogroups were revealed: E, F (including G and I), J, N3, P, and R1a1. These haplogroups were earlier detected in a study of Y-chromosome diversity on the territory of Europe as a whole. The major haplogroup in the Ukrainian gene pool, haplogroup R1a1 (earlier designated HG3), accounted for about 44% of all Y chromosomes in the sample examined. This haplogroup is thought to mark the migration patterns of the early Indo-Europeans and is associated with the distribution of the Kurgan archaeological culture. The second major haplogroup is haplogroup F (21.3%), which is a combination of the lineages differing by the time of appearance. Haplogroup P found with the frequency of 9.6%, represents the genetic contribution of the population originating from the ancient autochthonous population of Europe. Haplogroups J and E (11.7 and 4.2%, respectively) mark the migration patterns of the Middle-Eastern agriculturists during the Neolithic. The presence of the N3 lineage (9.6%) is likely explained by a contribution of the assimilated Finno-Ugric tribes. The data on the composition and frequencies of Y-chromosome haplogroups in the sample studied substantially supplement the existing picture of the male lineage distribution in the Eastern Slav population.     

The population gene pool of Yakutia: cartographic analysis based on the polymorphism of immune and biochemical markers

The gene pool of the indigenous population of Sakha Republic (Yakutia) has been studied within the borders of this republic coinciding with the main area of Yakuts, which was formed by the end of the 19th century and have remained stable until the present time. Maps of the geographic variation of the integrated characteristics of the Yakut gene pool, including the principal components, parameters of genetic diversity, and genetic distances from the "average" Yakut population are presented. It has been demonstrated that ethnographers' reports on intense internal assimilation in modem Yakutia agree with genetic data. The stratification of the Yakut gene pool reflected in the maps of two principal components corresponds to the observed general (H(T)) and interpopulation (FST) gene diversities.     

Population structure of Volga Tatars inferred from the mitochondrial DNA diversity data

The data on mitochondrial DNA (mtDNA) variation in two populations of Volga Tatars, representing the population of Buinsk and Aznakaevo districts of the Republic of Tatarstan are presented. Comparative analysis of the data on mtDNA variation in the populations of Eastern Europe showed that Volga Tatars were characterized by low interpopulation differentiation (F _ST = 0.33%), while the level of interethnic differentiation in Eastern Europe is 1.8%. Genetic similarity of Tatars from the eastern regions of Tatarstan to Bashkirs, as well as of Tatars from western regions to Chuvashes, with whom they share territorial borders, was revealed. Positive correlation between population genetic structure in Eastern Europe and linguistic affiliation of the ethnic groups studied was observed.     

Estimating the strength of selective sweeps from deep population diversity data

Selective sweeps are typically associated with a local reduction of genetic diversity around the adaptive site. However, selective sweeps can also quickly carry neutral mutations to observable population frequencies if they arise early in a sweep and hitchhike with the adaptive allele. We show that the interplay between mutation and exponential amplification through hitchhiking results in a characteristic frequency spectrum of the resulting novel haplotype variation that depends only on the ratio of the mutation rate and the selection coefficient of the sweep. On the basis of this result, we develop an estimator for the selection coefficient driving a sweep. Since this estimator utilizes the novel variation arising from mutations during a sweep, it does not rely on preexisting variation and can also be applied to loci that lack recombination. Compared with standard approaches that infer selection coefficients from the size of dips in genetic diversity around the adaptive site, our estimator requires much shorter sequences but sampled at high population depth to capture low-frequency variants; given such data, it consistently outperforms standard approaches. We investigate analytically and numerically how the accuracy of our estimator is affected by the decay of the sweep pattern over time as a consequence of random genetic drift and discuss potential effects of recombination, soft sweeps, and demography. As an example for its use, we apply our estimator to deep sequencing data from human immunodeficiency virus populations.     

Comparing activated sludge fungal community population diversity using denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism

We compared the relative values of denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) for profiling fungal communities in wastewater treatment plants using both ITS and 18S rRNA gene fragments as phylogenetic markers. A similar number of fungal ribotypes was obtained with both methods for the same treatment plant when the ITS primer set was used, while a greater number of ribotypes was obtained with T-RFLP compared to DGGE with the 18S rRNA primer set. Non-metric multi-dimensional scaling of presence/absence data and analysis of similarity showed that both methods could distinguish between the different plant communities at a statistically significant level (p < 0.05), regardless of which phylogenetic marker was used. The data suggest that both methods can be used preferably together to profile activated sludge fungal communities. A comparison of profiles generated with both these phylogenetic markers based on the number of ribotypes/bands, suggests that the 18S rRNA region is more discriminatory than the ITS region. Detected differences in fungal community compositions between plants probably reflect differences in their influent compositions and operational parameters.     

Gene pool and gene geography of the USSR population]

Gene pool and gene geography are discussed from the point of view of their conceptual history beginning from the original concept of A.S. Serebrovski? (1928). Difference between the present-day gene geography and gene geography of gene pool is accentuated: the former only represents a portion of the latter. Historical and territorial integrity of the USSR population gene pool, in conjunction with its huge diversity, is the main problem being analysed by various means of computerized genetic cartography. Coupled with the gene frequency mapping, following methods were also used: mapping of average heterozygosity, of interpopulation differentiation, of principal component scores and mapping of geographical trend for each mapped genetic parameter. The work is based on 100 allelic genes and haplotypes from 30 independent loci studied on the average in 225 local populations. Statistical analysis of gene geographical maps is based on 3975 nodes of regular cartographic net for the USSR territory. The wind rose of systematic changes in the USSR gene pool has three main geographic orientations: W-E, SW-NE and S-N. At the same time, there are only two main systematic forces of gene pool evolution: the force of social history with predominant W-E orientation and the force of natural history with predominant S-N orientation of their actions. The heterozygosity level of gene pool declines strictly in accordance with the resultant in the SW-NE direction.     

Paleolithic and neolithic lineages in the European mitochondrial gene pool.

Phylogenetic and diversity analysis of the mtDNA control region sequence variation of 821 individuals from Europe and the Middle East distinguishes five major lineage groups with different internal diversities and divergence times. Consideration of the diversities and geographic distribution of these groups within Europe and the Middle East leads to the conclusion that ancestors of the great majority of modern, extant lineages entered Europe during the Upper Paleolithic. A further set of lineages arrived from the Middle East much later, and their age and geographic distribution within Europe correlates well with archaeological evidence for two culturally and geographically distinct Neolithic colonization events that are associated with the spread of agriculture. It follows from this interpretation that the major extant lineages throughout Europe predate the Neolithic expansion and that the spread of agriculture was a substantially indigenous development accompanied by only a relatively minor component of contemporary Middle Eastern agriculturalists. There is no evidence of any surviving Neanderthal lineages among modern Europeans.     

Species relationship in the Pennisetum gene pool: enzyme polymorphism

Summary Variation in leaf esterases (EST), 6-phosphogluconate dehydrogenase (PGD), shikimate dehydrogenase (SKDH), leucine aminopeptidase (AMP), phosphoglucomutase (PGM) and malate dehydrogenase (MDH) is reported in the Pennisetum gene pool. In the primary gene pool, polymorphism for EST, AMP, SKDH was very high, as compared to the near-monomorphic isozymes of PGD. Two loci controlling leaf esterases Est-1 and Est-2, were identified in the primary gene pool. Differences in allelic frequency distribution of the polymorphic Est-1 locus occur between the cultivated and wild pearl millet. The prevalent alleles of Est-1 are absent in P. purpureum Schumach (secondary gene pool). A monomorphic band of the -esterase-specific Est-2 locus was identified in most of the secondary gene pool accessions, P. squamulatum Fresen and an accession of P. pedicellatum. SKDH and EST revealed differences between most of the tertiary gene pool species. By contrast, a PGD zymogram was prevalent in several species of different sectional taxa. Gene duplication for PGD isozymes occurs in the diploid species, P. ramosum, of the tertiary gene pool. Heterodimers of PGD and EST were observed in the hybrid between pearl millet and P. squamulatum, whereas a monomeric structure characterized SKDH and AMP.     

Comparative characteristics of the gene pool of Teleuts inferred from Y-chromosomal marker data

The gene pool structure of Teleuts was examined and Y-chromosomal haplogroups composition and frequencies were determined. In the gene pool of Teleuts, five haplogroups, C3×M77, N3a, R1b*, R1b3, and R1a1, were identified. Evaluation of the genetic differentiation of the samples examined using analysis of molecular variance (AMOVA) with two marker systems (frequencies of haplogroups and Y-chromosomal microsatellite haplotypes) showed that Bachat Teleuts were equally distant from Southern and Northern Altaians. In Siberian populations, the frequencies and molecular phylogeny of the YSTR haplotypes within Y-chromosomal haplogroup R1a1 were examined. It was demonstrated that Teleuts and Southern Altaians had very close and overlapping profiles of R1a1 haplotypes. Population cluster analysis of the R1a1 YSTR haplotypes showed that Teleuts and Southern Altaians were closer to one another than to all remaining Siberian ethnic groups. Phylogenetic analysis of N3a haplotypes suggested specificity of Teleut haplotypes and their closeness to those of Tomsk Tatars. Teleuts were characterized by extremely high frequency of haplogroup R1b*, distinguished for highly specific profile of YSTR haplotypes and high haplotype diversity. The results of the comparative analysis suggested that the gene pool of Bachat Teleuts was formed on the basis of at least two heterogeneous genetic components, probably associated with ancient Turkic and Samoyedic ethnic components.     

Genogeographic analysis of subdivided population. The Adyge gene pool in the Caucasian gene pool system]

A gene geographic analysis of the indigenous population of the Caucasian historical cultural province was carried out with a set of genetic markers extensively studied in the Adyges (39 alleles of 18 loci): AB0, ACP, C3, FY, GC, GLO, HP, KEL, LEW, MN, MNS, P, PGD, PGM1, RH-C, RH-D, RH-E, and TF. Genetic information on 160 Caucasian populations was used (on average, 65 populations per locus). A synthetic map of the first principal component clearly showed a division into two gene geographic provinces: Northern Caucasus and Transcaucasia. The component significantly differed across the Greater Caucasian Ridge. One of the major regions of extreme values corresponded to the Adyge region. A map of the second component revealed two poles, Northwestern (the Adyges) and Caspian, in gene pool variation of the Caucasian population. The analysis of the maps and the space of principal components showed that the Adyge population is an important component of the Caucasian gene pool. A map of genetic distance from all Caucasian populations to the Adyges showed that the north Caucasian populations (excluding the Ossetes) are the most genetically similar to the Adyges, while Georgians from the Kolkhida Valley and Azerbaijanians from the lowlands near the Caspian Sea and highland steppes are the most genetically remote from the Adyges. The genetic diversity (GST x 10(2)) of the entire Caucasian gene pool was studied. The average diversity of subpopulation within a Caucasian ethnos was GS-E = 0.81, the diversity of ethnoses within a linguistic family was GE-L = 0.83, and the diversity of linguistic families was GL-T = 0.58. The race classification of the Caucasian populations (GS-E = 0.81, GS-R = 0.80, GR-T = 0.76) proved to be more genetically informative than the linguistic one. The major parameters of the Adyges (total diversity HT = 0.364, heterozygosity HS = 0.361, and subpopulation diversity within the ethnos GS-E = 0.69) were similar to those averaged over the entire Caucasian population. A comparison with the same set of genetic markers showed that the interethnic diversity in the Caucasian region was lower than in the other north Eurasian regions (GS-E was 1.24 in the European region, 1.42 in the Ural region, 1.27 in Middle Asia, and 3.85 in Siberia).     

African DNA lineages in mitochondrial gene pool of Europeans

Mitochondrial DNA (mtDNA) nucleotide sequences of African origin have been found at low frequency (1%, in average) in different European populations. In the present study, data on mtDNA variability in populations of Eurasia and Africa are analyzed and search of African-specific lineages present in Europeans is conducted. The results of analysis indicate that, despite a high diversity of African mtDNA haplotypes found in Europeans, monophyletic clusters of African mtDNA lineages, arisen in Europe and characterized by long-term diversity, are nearly absent in Europe. Only two respective clusters (belonging to haplogroups L1b and L3b), which evolutionary age does not exceed 6.5 thousands years, were revealed. Comparative analysis of distribution of frequencies of autosomal microsatellite alleles found in Russian individuals, carrying the African-specific mitochondrial haplotypes, in populations of Europe and Africa has indicated that autosomal genotypes of those Russian individuals are characterized by the presence of alleles characteristic mostly for Europeans.