The ins and outs of population relationships in west-Mediterranean islands: data from autosomal <Emphasis Type="Italic">Alu</Emphasis> polymorphisms and <Emphasis Type="Italic">Alu</Emphasis>/STR compound systems

The islands of the West Mediterranean have played a central role in numerous archaeological, historical and anthropological studies due to their active participation in the history of main Mediterranean civilisations. However, genetic data failed to fit in both their degree of internal differentiation and relationships. A set of 18 Alu markers and three short tandem repeats (STRs) closely linked to the CD4, F13B and DM Alu have been analysed in seven samples from Majorca, Corsica, Sardinia and Sicily to explore some of these issues. Our samples show a high genetic heterogeneity inside and among islands for the Alu data. Global differentiation among islands (F_ST 2.2%) is slightly higher than that described for Europeans and North Africans. Both the estimated divergence times among samples and the high population heterogeneity revealed by Alu data are compatible with population differences since the first islands’ settlement in the Paleolithic period. However, the high within-population diversities and the remarkable homogeneity observed in both STR and Alu/STR haplotype variation indicated that, at least since Neolithic times, gene flow has been acting in west Mediterranean. Genetic drift in west-coast Sardinia and gene flow in west Sicily have contributed to their general differentiation, whereas Corsica, Majorca and east Sicily seem to reflect more recent historical relationships from continental south Europe. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Short tandem repeat (STR) variation in eight village populations of the island of Korcula (Croatia)

The aim of this study was to analyse short tandem repeat (STR) variation using the data on nine loci (D3S1358, vWA, FGA, THO1, TPOX, CSF1PO, D5S818, D13S317, D7S820) in the populations from eight villages on the island of Korcula, Croatia, in order to analyse its genetic and population structure. The analysis of STR data in this study indicated an appreciable degree of genetic homogeneity among the studied village populations on the island, even though a so-called 'east-west dichotomy' and differentiation between the inhabitants of the most recent settlement and the remaining ones was indicated with respect to the loci CSF1PO and TPOX, respectively. The validity of STR markers in assessing genetic structure of small populations and especially in determining the relationships among geographically closely related but reproductively isolated groups remains to be further evaluated, especially in terms of a larger number of studied loci in order to possibly find specific markers useful for resolving genetic patterns of variability at regional levels.     

Origin and evolution of two Yugur sub-clans in Northwest China: a case study in paternal genetic landscape

Background: Yugur is an ethnic group that was officially identified by the Chinese Government in 1953. Within the population there are two sub-clans distinctly identified as the Eastern Yugur and Western Yugur, partly because they have different local languages.

Aim: A parentage comparison was conducted between the two sub-clans to investigate their genetic relationship.

Subjects and methods: Male subjects were chosen from the two clans to investigate their paternal genetic landscape through typing 14 single nucleotide polymorphisms (SNP) and 12 short tandem repeats (STR) of the Y chromosome.

Results: Significant differences were revealed between the sub-clans at the haplogroup level. Genetic divergence was also observed by analyses of multidimensional scaling (MDS) and principal components (PC). Genetically, the Eastern Yugur are closer to the Han Chinese and Mongolian people than the Western Yugur. The Uygur people, who share a common ancestor (ancient Huihu) with the Yugur, were genetically separate from both sub-clans of Yugur. Moreover, the constructed phylogenetic network for haplogroup O provided further evidence that the two Yugur sub-groups present an underlying genetic difference.

Conclusion: Overall, the diffusion of Mongolians during the Mongol Period has affected the Eastern Yugur more than the Western Yugur. The genetic contribution of the Han people to the Eastern Yugur seems to be more pronounced than to the Western Yugur. Besides the two different contributions referred to above, small population size and genetic drift have resulted in the genetic differentiation of the current sub-clans of Yugur.     

Genetic variability of diurnally sub-periodic <Emphasis Type="Italic">Wuchereria bancrofti</Emphasis> in Nicobarese tribe of Nicobar group of Islands,Andaman and Nicobar Islands,India

Sub-periodic form of Wuchereria bancrofti occurs in several well-isolated islands of Nicobar group of islands of Andaman Nicobar archipelago, India, presenting an interesting situation to study the genetic variability of its population. Microfilariae collected from 40 microfilaria (mf) carriers residing in eight locations on five islands (five carriers from each locality) were studied for genetic variability by generating random-amplified polymorphic DNA profiles. Phylognetic analysis of the profiles revealed a considerable genetic variability among parasite populations of different islands. The Nei’s gene diversity between populations of 40 individual mf carriers ranged from 0.0218 to 0.2400. It was highest (0.24) among the parasite populations of Car Nicobar island and lowest (0.0218) among those of Payuha area of Camorta island and Teressa island. The dendrogram constructed exhibited four distinct clusters, which are geographically localized, and the gene flow between them appears to be influenced by human migration pattern.     

Genetic characterisation of 19 autosomal STR loci in a population sample from the Southeastern Anatolia Region of Turkey

Background: Southeastern Anatolia is the smallest, yet the most densely populated region among the seven major geographic constituents of Turkey. Situated in the Upper Mesopotamia, Southeastern Anatolia was also the northernmost extension of the Fertile Crescent, which is often considered as the earliest cradle of civilisation.

Aim: To investigate the autosomal STR polymorphisms associated with a truly representative population sample pool from Southeastern Anatolia.

Subjects and methods: Samples from a total of 257 volunteers were analysed by 19-loci autosomal STRs using the commercially available COrDIS Plus Kit. Allele frequencies, statistical parameters of forensic interest and Nei’s D_A distances with respect to the nearby and distant populations were calculated, besides performing exact tests of population differentiation with the same populations.

Results: A combined matching probability of 1.49978?×?10^?23 and a combined power of exclusion of 0.999999961 were obtained for the novel Southeastern Anatolian autosomal STR dataset. Furthermore, the Southeastern Anatolia population was found to have close genetic affinities with the other regional populations from Turkey, along with those from an apparent genetic continuum extending from the Near East to Southeastern Europe.

Conclusions: The novel Southeastern Anatolian dataset is expected to be useful in regional forensic genetics investigations and molecular anthropology applications.     

Genetic polymorphisms of 20 autosomal STR loci in the Han population of Putian City,Southeastern China

Abstract

Background: Short tandem repeats (STRs) are genetic markers that are more informative than single nucleotide polymorphisms and they are widely used in forensic DNA analysis.

Aim: To carry out the genetic analysis of 20 autosomal STR loci in Han individuals of Putian City, Southeast China, to expand the available population information for human genetic databases and forensic analysis.

Subjects and methods: Saliva swabs from 1417 unrelated Chinese Han individuals from Putian City of Southeast China were collected and then genotyped using the SureID^® 21G Human STR Identification Kit. Moreover, phylogenetic analysis based on the Nei’s standard genetic distance was performed between the Han population and other relevant populations based on the shared autosomal STR genotyping.

Results: We found 272 alleles among 1417 unrelated individuals and the corresponding allelic frequencies ranged from 0.5409 to 0.0004. The combined power of exclusion (CPE) was 0.999999995514, and the combined power of discrimination (CPD) was 0.9999999999999999999999994061. Population comparison revealed that the Putian Han population makes a cluster with other Han populations from China while showing significant differences when compared with other worldwide populations.

Conclusions: Our results found that the SureID^® 21G Human STR Identification Kit panel was appropriate for forensic identity testing and paternity testing. Putian Han population had a closer genetic relationship with Han populations from other regions in China, while other minorities like Uighurs and Kazakhs from China showed significant differences.     

Population genetic polymorphism and mutation analysis of 19 autosomal STR loci in Jiangsu Han individuals in Eastern China

Aim: Genetic polymorphisms and the mutation ratio of 19 autosomal short tandem repeat (STR) loci were analysed in 10,000 individuals and 7755 families from Jiangsu Province in Eastern China.

Subjects and methods: Nineteen STR loci were amplified by a multiplex amplification system and genotyped on the ABI 3130 Genetic Analyser. Allele frequencies, forensic parameters and mutations for the 19 autosomal STR loci were statistically analysed.

Results: In total, 344 genotypes were discovered. No significant deviation from Hardy-Weinberg equilibrium was observed. The combined power of discrimination reached 0.9999999999999999984341, and the combined probability of paternity exclusion was 0.999999989. The pairwise genetic distance and p-values between the Jiangsu and 17 published populations depended on the F_ST value calculation and are shown by the neighbour-joining evolutionary tree. No statistically significant differences were found, except for the Xinjiang Altay Han (p?=?0.01802) population. The average mutation rate of the Jiangsu population across all 19 loci was 1.4?×?10^?3. The average mutation rate of the 13 core CODIS STR loci remained below 2?×?10^?3 and there was no difference and relatively high consistency (p?<?0.001) by correlation coefficient analysis among the six groups.

Conclusions: Allelic genetic polymorphisms and mutation data were obtained from a large number of samples, which indicated that the amplification kit is suitable for forensic application and that the Jiangsu population has its own genetic characteristics that are different from those of other ethnic populations.     

Mitochondrial DNA variation in an isolated area of Central Italy

Abstract

Background: The genetic variation in Italy is the result of ancient population movement, demographic change, and geography. The increasing possibility of studying the maternal genetic structure of selected Italian population samples at a high level of phylogenetic resolution provides a particularly useful model to assess the presence of genetic traces of the ancient people who lived in Italy in pre-Roman times in present populations

Aim: In this study we reconstructed the genetic maternal history of Jenne and Vallepietra, two mountain communities in the Aniene Valley in the Simbruini Mountains near Rome. Both communities have been spared external invasion due to their geographic location, which very likely preserved the genetic pool of these autochthonous populations.

Subjects and methods: The study population (124 individuals from Jenne and Vallepietra) were investigated for D-loop mtDNA hypervariable segments I (HVS-I) and II (HVS-II) and for informative single nucleotide polymorphisms (SNPs) within the coding region. The detected haplotypes were then compared with those of other Italian, European and Mediterranean populations.

Results: The distribution of mtDNA diversity in Jenne and Vallepietra, although similar to that found in other European populations, shows a basic variability and the typical signs of a certain degree of isolation between them and other populations analysed; in particular, the Vallepietra sample showed an unusually high frequency (71.3%) of mtDNA haplogroups which are typical of Near Eastern and South-Western Asian populations.

Conclusion: The high degree of differentiation between the two villages is intriguing, since it suggests a low level of gene flow between them, despite their close geographic proximity and shared linguistic features. The degree of their genetic isolation, also in comparison to other Italian, European and Mediterranean populations, is consistent with isolation among geographically separated populations.     

The landscape of Y chromosome polymorphisms in Russia

Abstract

Background: The pattern of diversity for the Y chromosome provides a view of male-driven processes of dispersal and settlement. By virtue of the broad geographic continuity, the genetic signature of movements from Asia to Europe can be detected in populations of north-eastern Europe.

Aim: To directly test previous hypotheses on the peopling of Russia, by considering a broader spectrum of potential diversity.

Subjects and methods: A total of 636 unrelated males (24 samples) from geographically and ethnically defined populations of Russia, Belarus, Azerbaijan and Georgia were analysed for 16 Y-STR loci. Some of the populations represent more or less distinct isolates.

Results: Microsatellites alone can have the power of detecting Asian contributions to the gene pool of populations now residing in Europe. Within Europe, a greater heterogeneity among populations sharing the same language than between populations sharing the same ethnic affiliation was found. There was low diversity and marked population differentiation in some Altaic speakers. Sympatry eroded inter-ethnic differentiation. No regular decline in genetic similarity with geography was seen.

Conclusion: Two layers of overall diversity represent a main feature of the genetic landscape of the population of the European portion of Russia.     

Origin and genetic differentiation of three Native Mexican groups (Purépechas,Triquis and Mayas): Contribution of CODIS-STRs to the history of human populations of Mesoamerica

Background: CODIS-STRs in Native Mexican groups have rarely been analysed for human identification and anthropological purposes.

Aim: To analyse the genetic relationships and population structure among three Native Mexican groups from Mesoamerica.

Subjects and methods: 531 unrelated Native individuals from Mexico were PCR-typed for 15 and 9 autosomal STRs (Identifiler? and Profiler? kits, respectively), including five population samples: Purépechas (Mountain, Valley and Lake), Triquis and Yucatec Mayas. Previously published STR data were included in the analyses.

Results: Allele frequencies and statistical parameters of forensic importance were estimated by population. The majority of Native groups were not differentiated pairwise, excepting Triquis and Purépechas, which was attributable to their relative geographic and cultural isolation. Although Mayas, Triquis and Purépechas-Mountain presented the highest number of private alleles, suggesting recurrent gene flow, the elevated differentiation of Triquis indicates a different origin of this gene flow. Interestingly, Huastecos and Mayas were not differentiated, which is in agreement with the archaeological hypothesis that Huastecos represent an ancestral Maya group. Interpopulation variability was greater in Natives than in Mestizos, both significant.

Conclusion: Although results suggest that European admixture has increased the similarity between Native Mexican groups, the differentiation and inconsistent clustering by language or geography stresses the importance of serial founder effect and/or genetic drift in showing their present genetic relationships.     

Evaluation of linkage disequilibrium on the Xq13.3 region: Comparison between the Azores islands and mainland Portugal

The design of genetic studies of complex diseases is dependent on the extent and distribution of linkage disequilibrium (LD) across the genome in different populations. Here, we characterize the extent of LD in the Azores (Western, Central, and Eastern island groups) and mainland Portugal populations. LD was evaluated in the Xq13.3 region by genotyping eight STR markers spanning 20.9 Mb. Standardized multiallelic disequilibrium coefficient (D′) analysis indicates that the Western group presents higher values when compared with the Central and Eastern groups. However, all island groups show values of D′ lower than 0.5 and 0.33, suggesting no extensive LD in these populations. Taken together, the data show that the Azorean population presents a lower D′ (0.142) than mainland Portugal (0.226). Although, both populations do not show extensive LD, the easy reconstruction of large pedigrees in the Azorean population is a valuable resource for the fine mapping of disease genes. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.     

3000 years of solitude: extreme differentiation in the island isolates of Dalmatia, Croatia

Communities with increased shared ancestry represent invaluable tools for genetic studies of complex traits. "1001 Dalmatians" research program collects biomedical information for genetic epidemiological research from multiple small isolated populations ('metapopulation') in the islands of Dalmatia, Croatia. Random samples of 100 individuals from 10 small island settlements (n<2000 inhabitants) were collected in 2002 and 2003. These island communities were carefully chosen to represent a wide range of distinct and well-documented demographic histories. Here, we analysed their genetic make-up using 26 short tandem repeat (STR) markers, at least 5 cM apart. We found a very high level of differentiation between most of these island communities based on Wright's fixation indexes, even within the same island. The model-based clustering algorithm, implemented in STRUCTURE, defined six clusters with very distinct genetic signatures, four of which corresponded to single villages. The extent of background LD, assessed with eight linked markers on Xq13-21, paralleled the extent of differentiation and was also very high in most of the populations under study. For each population, demographic history was characterised and 12 "demographic history" variables were tentatively defined. Following stepwise regression, the demographic history variable that most significantly predicted the extent of LD was the proportion of locally born grandparents. Strong isolation and endogamy are likely to be the main forces maintaining this highly structured overall population.     

Structure and genetic relationship of five populations from central India based on 15 autosomal STR loci

Aim: To estimate population parameters based on allele frequencies obtained for 15 polymorphic autosomal STR loci investigated in caste and tribal populations of central India (n?=?419).

Methods: Multiplexed PCR amplifications of the 15 Autosomal STR Loci were performed and amplified products were genotyped using multi-capillary electrophoresis on an ABI 3100 genetic analyser. Parameters of population genetics and forensic interest based on the allele frequencies were calculated. Genetic affinity of the studied populations among themselves and with previously reported populations of India was also analysed using distance-based NJ tree and using PCA plot.

Results: All the 15 STR loci were highly informative and discriminating, with CPD of 0.999 99. Except for Brahmins and Rajput, all other studied populations were in Hardy–Weinberg equilibrium (HWE). The only tribe (Gond) population studied showed significant variation with the other four caste populations (Brahmin, Yadav, Rajput and Muslim) studied and formed a cluster with other previously reported tribal populations of India. Nei’s genetic distance based clustering pattern of the NJ tree and the PCA plot showed the same pattern of genetic relationship, i.e. caste and tribal populations formed a distinct cluster.

Conclusions: With respect to the distribution of alleles at each STR locus, the studied loci were found to be substantially polymorphic in all the studied populations, indicating good informativeness of all 15 STR markers. The population data generated in this study are useful for forensic, anthropological and demographic studies.     

Investigation of the genetic structure of Kabyle and Chaouia Algerian populations through the polymorphism of Alu insertion markers

Abstract

Background: In Algeria, as in all North Africa, Berbers constitute the old background of the population. Today, Berber speakers account for only ～ 25% of Algerians. This decline is the product of a complex human settlement from pre-history to recent invaders.

Aim: This study aims to determine the genetic diversity level within a sample of five Algerian Berber speaking populations in order to contribute to resolving issues about the North African population settlement.

Subjects and methods: Two Algerian Berber groups (Kabyle and Chaouia), originated from five administrative regions from Algeria, were typed for 11 Alu Insertions. Analysis has been based on Fst genetic distance, AMOVA, NMDS and distance to the centroid model.

Results: No genetic differentiation has been observed between all Algerian Berbers discarding any geographical or ethnic effect. Comparative analyses based on Fst genetic distance did not show significant affinities between North Africans and either South Europeans or Middle Easterners, except genetic proximity between Algerians and Iberians. The amount of genetic diversity among Algerians and North African populations detected by the distance to the centroid model was significant compared with other North Mediterranean populations.

Conclusion: A strong genetic homogeneity has been found between Algerian Berbers. Global genetic diversity based on Alu markers is following the isolation by distance model, except for some European populations.     

Polymorphisms at locus D1S80 and other hypervariable regions in the analysis of Eastern European ethnic group relationships

Background: It has been hypothesized that, whereas many loci are used to generate phylogenetic relationships, the utilization of those that yield the most information could increase the accuracy of any multilocus phylogenetic reconstruction. Among these is the D1S80 hypervariable minisatellite region, which has been shown to be highly polymorphic globally, and it was of interest to compare the nearest neighbours and distant populations of Eastern Europe using the D1S80 polymorphism.

Aim: The study evaluated the capacity of the D1S80 locus to discriminate between populations from different ethnic groups in Russia and the Republic of Belarus, revealing the polymorphism parameters of the populations studied.

Subjects and methods: Hypervariable D1S80 minisatellite polymorphism was studied in 15 populations, belonging to six distinct ethnic groups from the Russian Federation (Russians, Komis, Maris, Udmurts, Kalmyks, and Yakuts) and the Republic of Belarus (Byelorussians). The data were analysed with other results reported for D1S80 polymorphism among Eastern Europeans, and were analysed together with those previously reported for Eastern European populations for the 3′ApoB, DMPK, DRPLA, and SCA1 hypervariable loci. Genetic diversity analysis was carried out using multidimensional scaling (MDS) of Nei's genetic distances.

Results: The Eastern Slavonic populations (Russians, Ukrainians, and Byelorussians) are closely associated, and outermost from populations of Asian origin (Kalmyks and Yakuts). The populations that inhabit the Volga–Ural region (Udmurt, Komi, Mari, and Bashkir ethnic groups) revealed intermediate characteristics.

Conclusion: The clustering of populations demonstrated here using D1S80 alone coincides with the analysis of five hypervariable region (HVR) loci, and is consistent with linguistic, geographic, and ethnohistorical data. These results are in agreement with most studies of mtDNA, Y-chromosomal, and autosomal DNA diversity in Eastern Europe. The D1S80 locus is convenient for population analyses, and may be used as part of a set of similar markers, which should allow the easy resolution of small differences in population structures.     

Society for the Study of Human Biology

Background: The present study examines genomic variation among eight endogamous groups (Bania, Kamboh, Lobana, Saini, Bishnoi, Sansi, Balmiki and Ramdasia) of Haryana, north-west India.

Aim: The present study examines the eight indel polymorphic loci in the population of Haryana. These loci were further used to compare the genomic diversity of the population in relation to other population groups of India.

Subjects and methods: DNA samples from 580 unrelated individuals belonging to eight endogamous groups were analysed at eight human-specific insertion/deletion polymorphic loci following standard protocols.

Results: All loci, except Alu CD4 and Alu APO, were found to be highly polymorphic. High average heterozygosity values (0.3886 among Kamboh to 0.4276 among Bishnoi) were observed. The overall coefficient of gene differentiation (0.0270) was found to be remarkably close to the Wahlund's variance (0.0258). Comparison with other Indian populations showed that populations of the same geographic region tend to cluster together, irrespective of their social status.

Conclusion: In various endogamous groups of Haryana, the time of divergence seems to be too small to reflect the genetic differences between them. It may be possible that gene flow occurred prior to the sub-division into the present endogamous groups or the present populations might have the same sources of genes resulting in a low level of genetic differentiation. Populations of Haryana were found to be more similar with populations of the neighbouring states of Punjab and Uttar Pradesh.     

Polymorphism analysis and evaluation of nine non-CODIS STR loci in the Han population of Southern China

Background: Knowledge of allele and genotype frequencies is an essential prerequisite to the use of any human polymorphism in forensic work.

Aim: To study the genetic polymorphism and evaluate the application value of nine STR loci.

Subjects and methods: Genotyping of nine STR loci, including D11S2368, D12S391, D13S325, D18S1364, D22-GATA198B05, D6S1043, D2S1772, D7S3048 and D8S1132, of 1050 unrelated individuals was performed with the STR_Typer_10_v1 kit and Genetic Analyzer 3100 and analyzed with PowerState V12.xls and Arlequin ver 3.11 analyzing software.

Results: Allele frequency distribution was statistically analyzed and Hardy–Weinberg equilibrium determined. Several common parameters used in forensic sciences were found: the heterozygosity (H) ranged from 0.827 to 0.892; the matching probability (MP) ranged from 0.029 to 0.074; the power of discrimination (PD) ranged from 0.926 to 0.971; the power of exclusion (PE) ranged from 0.649 to 0.779; the polymorphic information content (PIC) ranged from 0.77 to 0.86; and the typical paternity index (TPI) ranged from 2.88 to 4.62.

Conclusion: The results indicate that nine STR loci are high polymorphic among the Han population in Southern China. This set of polymorphic STR loci is a useful tool in forensic paternity testing and anthropological study.     

Comparative mtDNA phylogeographic patterns reveal marked differences in population genetic structure between generalist and specialist ectoparasites of the African penguin (Spheniscus demersus)

To address factors affecting genetic diversity and dispersal of ectoparasites, we compared mitochondrial DNA (mtDNA) population genetic structures of the generalist soft tick Ornithodoros capensis to the more host-specific nest flea Parapsyllus humboldti. A total of 103 ticks and 92 fleas were sampled at five distinct South African island/mainland African penguin (Spheniscus demersus) colonies. With its wide host range, O. capensis showed no evidence of significant cytochrome c oxidase subunit I (COI) mtDNA population differentiation among the five sampling sites (φ_st = 0.00 ± 0.004; p = 0.80), as well as a higher level of genetic diversity (π = 0.8% ± 0.06%) when compared to P. humboldti. In contrast, the flea showed significant population structure among most of the same sampling sites (φ_st = 0.22 ± 0.11; p ≤ 0.05) and a lower level of genetic diversity (π = 0.2% ± 0.01%). Our findings suggest that despite both parasites being mostly nest bound, O. capensis have few barriers to dispersal among island and mainland colonies. However, P. humboldti are more dependent on the African penguin for dispersal and thus have more impediments to gene flow among the same colonies. These findings broadly support the SGVH (specialist generalist variation hypothesis) and provide the first evidence for this hypothesis in parasites restricted to seabird colonies.

     

Genetic sub-structuring of Croatian island populations in the Southeastern European context: a meta-analysis

AimTo use the method of meta-analysis to assess the influence of island population isolation on the sub-structuring of the Croatian population, as well as the influence of regional population groups on the sub-structuring of the Southeastern European population with regard to basic population genetic statistical parameters calculated by using STR locus analysis.MethodsBio-statistical analyses were performed for 2877 unrelated participants of both sexes from Southeastern Europe. Nine autosomal STR loci (D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S82) were analyzed by using standard F-statistics and population structure analysis (Structure software).ResultsGenetic differentiation of Croatian subpopulations assessed with the F_ST method was higher at the level of the Croatian population (0.005) than at the level of Southeastern Europe (0.002). The island of Vis showed the most pronounced separation in the Croatian population, and Albanians from Kosovo in the population of Southeast Europe, followed by Croatia, Bosnia and Herzegovina, and Hungary.ConclusionThe higher structure of Croatian subpopulations in relation to Southeastern Europe suggest a certain degree of genetic isolation, most likely due to the influence of endogamy within rural island populations.

The island populations of the eastern Adriatic have been the subject of multidisciplinary anthropological research for almost 50 years, starting with the pioneering work of Rudan et al in 1972 (1). A number of specific features of these rural populations has been revealed, which make them exceptional models for studying ethno-cultural, historical, migratory, and demographic characteristics of this region. More specifically, evolutionary forces (bottleneck effect and genetic drift) increase genome homogeneity within the genetic structure of such island isolates by eliminating certain genetic traits in favor of others and increasing the likelihood of finding low-impact alleles (2,3). The reduced genetic and environmental diversity makes genetically isolated populations suitable for the study of different complex and rare Mendelian hereditary diseases, since the combined action of genetic drift, inbreeding, and founder effect increases the prevalence of such diseases when compared with the general population.Southeastern Europe was one of Europe’s glacial refugia during the ice age, and the origin of postglacial resettlement of Europe in the Paleolithic and Neolithic. Due to this specific role and its position at the crossroads of migrations to and from Europe, this area was extensively investigated in the field of population genetics (4-7). Different genetic markers have been used to investigate the genetic landscape of Europe and determine the patterns of population sub-structuring at the regional and continental level (8). As a part of the comprehensive anthropological research on the population structure of Croatian island isolates, microsatellite DNA from different subpopulations has been previously analyzed to determine genetic diversity, population structure, and the degree of isolation of island populations (9). Similar studies were also conducted on a representative sample of the general Croatian population and other isolated populations from Southeastern Europe (10-12).This study represents a continuation of previous anthropogenetic research (6,13-16). We used statistical and analytical methods of meta-analysis to synthesize data from previously conducted, mutually independent studies of island and continental populations of Croatia and Southeastern Europe (Figure 1) based on analyses of autosomal STR markers, and data analyzed in this study for the first time.Open in a separate windowFigure 1Division of the sample into two hierarchical groups (left) and geographical position of the investigated Croatian subpopulations (right). NDI – North Dalmatian islands.The aim of this study was to determine the genetic characteristics of populations from Southeastern Europe, with special reference to Croatian island populations, and to investigate the effect of specific intrapopulation genetic structure on interpopulation relationships. Namely, a specific aim was to investigate the influence of island population isolation on the sub-structuring of the Croatian population, and the influence of regional population groups on the sub-structuring of Southeastern Europe with regard to basic population genetic statistical parameters calculated by using STR locus analysis.     

Genetic variation and relationships at six VNTR loci in two distinct sample populations in Brazil

Background: The Brazilian population has been the focus of intensive genetic study due to admixture characteristics whereas there are few reports on the variability of VNTR loci in Brazil.

Primary objective: The aim of this study was to analyse genetic parameters in sample populations from two geographically distant regions: São Luís City, in Maranhão State and Campinas City, in São Paulo State. We investigated if distinct colonization influences could produce detectable differences in genetic background.

Subject and methods: DNA samples from peripheral drained blood were obtained from unrelated individuals who underwent paternity testing. Allelic variation in six VNTR loci (D2S44, D4S139, D5S110, D8S358, D10S28 and D17S79) was evaluated. The results were compared to reference databases available for general Latin-derived European and African–American populations as well as for other Brazilian groups.

Results: This study reveals that forensic population parameters did not show differences among regions, although we detected admixture values varying between the south-east and north-east of Brazil.

Conclusions: Differences between the two samples are probably due to different admixture proportions of European- and African-derived alleles in each region; both populations are in Hardy–Weinberg equilibrium. In addition, the allelic frequency for all loci, in both populations, can be used as database for forensic purposes.