Contemporary paternal genetic landscape of Polish and German populations: from early medieval Slavic expansion to post-World War II resettlements

The Spectrum of Disease-Associated Alleles in Countries with a Predominantly Slavic Population

There are more than 260 million people of Slavic descent worldwide, who reside mainly in Eastern Europe but also represent a noticeable share of the population in the USA and Canada. Slavic populations, particularly Eastern Slavs and some Western Slavs, demonstrate a surprisingly high degree of genetic homogeneity, and, consequently, remarkable contribution of recurrent alleles associated with hereditary diseases. Along with pan-European pathogenic variants with clearly elevated occurrence in Slavic people (e.g., ATP7B c.3207C>A and PAH c.1222C>T), there are at least 52 pan-Slavic germ-line mutations (e.g., NBN c.657_661del and BRCA1 c.5266dupC) as well as several disease-predisposing alleles characteristic of the particular Slavic communities (e.g., Polish SDHD c.33C>A and Russian ARSB c.1562G>A variants). From a clinical standpoint, Slavs have some features of a huge founder population, thus providing a unique opportunity for efficient genetic studies.

Evidence for dynastic succession among early Celtic elites in Central Europe

The early Iron Age (800 to 450 BCE) in France, Germany and Switzerland, known as the 'West-Hallstattkreis', stands out as featuring the earliest evidence for supra-regional organization north of the Alps. Often referred to as 'early Celtic', suggesting tentative connections to later cultural phenomena, its societal and population structure remain enigmatic. Here we present genomic and isotope data from 31 individuals from this context in southern Germany, dating between 616 and 200 BCE. We identify multiple biologically related groups spanning three elite burials as far as 100 km apart, supported by trans-regional individual mobility inferred from isotope data. These include a close biological relationship between two of the richest burial mounds of the Hallstatt culture. Bayesian modelling points to an avuncular relationship between the two individuals, which may suggest a practice of matrilineal dynastic succession in early Celtic elites. We show that their ancestry is shared on a broad geographic scale from Iberia throughout Central-Eastern Europe, undergoing a decline after the late Iron Age (450 BCE to ~50 CE).

Genetic diversity in Kashubs: the regional increase in the frequency of several disease-causing variants

Differential distribution of genetic variants’ frequency among human populations is caused by the genetic drift in isolated populations, historical migrations, and demography. Some of these variants are identical by descent and represent founder mutations, which — if pathogenic in nature — lead to the increased frequency of otherwise rare diseases. The detection of the increased regional prevalence of pathogenic variants may shed light on the historical processes that affected studied populations and can help to develop effective screening and diagnostic strategies as a part of personalized medicine. Here, we discuss the specific genetic diversity in Kashubs, the minority group living in northern Poland, reflected in the biased distribution of some of the repetitively found disease-causing variants. These include the following: (1) c.662A > G (p.Asp221Gly) in LDLR, causing heterozygous familial hypercholesterolemia; (2) c.3700_3704del in BRCA1, associated with hereditary breast and ovarian cancer syndrome; (3) c.1528G > C (p.Glu510Gln) in HADHA, seen in long-chain 3-hydroxy acyl-CoA dehydrogenase (LCHAD) deficiency, and (4) c.1032delT in NPHS2, associated with steroid-resistant nephrotic syndrome.

The Ancestry of Eastern Paraguay: A Typical South American Profile with a Unique Pattern of Admixture

Immigrants from diverse origins have arrived in Paraguay and produced important demographic changes in a territory initially inhabited by indigenous Guarani. Few studies have been performed to estimate the proportion of Native ancestry that is still preserved in Paraguay and the role of females and males in admixture processes. Therefore, 548 individuals from eastern Paraguay were genotyped for three marker sets: mtDNA, Y-SNPs and autosomal AIM-InDels. A genetic homogeneity was found between departments for each set of markers, supported by the demographic data collected, which showed that only 43% of the individuals have the same birthplace as their parents. The results show a sex-biased intermarriage, with higher maternal than paternal Native American ancestry. Within the native mtDNA lineages in Paraguay (87.2% of the total), most haplogroups have a broad distribution across the subcontinent, and only few are concentrated around the Paraná River basin. The frequency distribution of the European paternal lineages in Paraguay (92.2% of the total) showed a major contribution from the Iberian region. In addition to the remaining legacy of the colonial period, the joint analysis of the different types of markers included in this study revealed the impact of post-war migrations on the current genetic background of Paraguay.

Phylogeographic review of Y chromosome haplogroups in Europe

The Y chromosome has been widely explored for the study of human migrations. Due to its paternal inheritance, the Y chromosome polymorphisms are helpful tools for understanding the geographical distribution of populations all over the world and for inferring their origin, which is really useful in forensics. The remarkable historical context of Europe, with numerous migrations and invasions, has turned this continent into a melting pot. For this reason, it is interesting to study the Y chromosome variability and how it has contributed to improving our knowledge of the distribution and development of European male genetic pool as it is today. The analysis of Y lineages in Europe shows the predominance of four haplogroups, R1b-M269, I1-M253, I2-M438 and R1a-M420. However, other haplogroups have been identified which, although less frequent, provide significant evidence about the paternal origin of the populations. In addition, the study of the Y chromosome in Europe is a valuable tool for revealing the genetic trace of the different European colonizations, mainly in several American countries, where the European ancestry is mostly detected by the presence of the R1b-M269 haplogroup. Therefore, the objective of this review is to compile the studies of the Y chromosome haplogroups in current European populations, in order to provide an outline of these haplogroups which facilitate their use in forensic studies.

Y-Chromosome Genetic Analysis of Modern Polish Population

The study presents a full analysis of the Y-chromosome variability of the modern male Polish population. It is the first study of the Polish population to be conducted with such a large set of data (2,705 individuals), which includes genetic information from inhabitants of all voivodeships, i.e., the first administrative level, in the country and the vast majority of its counties, i.e., the second level. In addition, the available data were divided into clusters corresponding to more natural geographic regions. Genetic analysis included the estimation of F_ST distances, the visualization with the use of multidimensional scaling plots and analysis of molecular variance. Y-chromosome binary haplogroups were classified and visualized with the use of interpolation maps. Results showed that the level of differentiation within Polish population is quite low, but some differences were indicated. It was confirmed that the Polish population is characterized by a high degree of homogeneity, with only slight genetic differences being observed at the regional level. The use of regional clustering as an alternative to counties and voivodeships provided a more detailed view of the genetic structure of the population. Those regional differences identified in the present study highlighted the need for additional division of the population by cultural and ethnic criteria in such studies rather than just by geographical or administrative regionalization.

Y-chromosomal connection between Hungarians and geographically distant populations of the Ural Mountain region and West Siberia

Hungarians who live in Central Europe today are one of the westernmost Uralic speakers. Despite of the proposed Volga-Ural/West Siberian roots of the Hungarian language, the present-day Hungarian gene pool is highly similar to that of the surrounding Indo-European speaking populations. However, a limited portion of specific Y-chromosomal lineages from haplogroup N, sometimes associated with the spread of Uralic languages, link modern Hungarians with populations living close to the Ural Mountain range on the border of Europe and Asia. Here we investigate the paternal genetic connection between these spatially separated populations. We reconstruct the phylogeny of N3a4-Z1936 clade by using 33 high-coverage Y-chromosomal sequences and estimate the coalescent times of its sub-clades. We genotype close to 5000 samples from 46 Eurasian populations to show the presence of N3a4-B539 lineages among Hungarians and in the populations from Ural Mountain region, including Ob-Ugric-speakers from West Siberia who are geographically distant but linguistically closest to Hungarians. This sub-clade splits from its sister-branch N3a4-B535, frequent today among Northeast European Uralic speakers, 4000-5000 ya, which is in the time-frame of the proposed divergence of Ugric languages.

Mitochondrial DNA variability of the Polish population

The aim of the present study was to define the mtDNA variability of Polish population and to visualize the genetic relations between Poles. For the first time, the study of Polish population was conducted on such a large number of individuals (5852) representing administrative units of both levels of local administration in Poland (voivodeships and counties). Additionally, clustering was used as a method of population subdivision. Performed genetic analysis, included F_ST, MDS plot, AMOVA and SAMOVA. Haplogroups were classified and their geographical distribution was visualized using surface interpolation maps. Results of the present study showed that Poles are characterized by the main West Eurasian mtDNA haplogroups. Furthermore, the level of differentiation within the Polish population was quite low but the existing genetic differences could be explained well with geographic distances. This may lead to a conclusion that Poles can be considered as genetically homogenous but with slight differences, highlighted at the regional level. Some patterns of variability were observed and could be explained by the history of demographic processes in Poland such as resettlements and migrations of women or relatively weaker urbanisation and higher rural population retention of some regions.

Whole Y-chromosome sequences reveal an extremely recent origin of the most common North African paternal lineage E-M183 (M81)

E-M183 (E-M81) is the most frequent paternal lineage in North Africa and thus it must be considered to explore past historical and demographical processes. Here, by using whole Y chromosome sequences from 32 North African individuals, we have identified five new branches within E-M183. The validation of these variants in more than 200 North African samples, from which we also have information of 13 Y-STRs, has revealed a strong resemblance among E-M183 Y-STR haplotypes that pointed to a rapid expansion of this haplogroup. Moreover, for the first time, by using both SNP and STR data, we have provided updated estimates of the times-to-the-most-recent-common-ancestor (TMRCA) for E-M183, which evidenced an extremely recent origin of this haplogroup (2,000-3,000 ya). Our results also showed a lack of population structure within the E-M183 branch, which could be explained by the recent and rapid expansion of this haplogroup. In spite of a reduction in STR heterozygosity towards the West, which would point to an origin in the Near East, ancient DNA evidence together with our TMRCA estimates point to a local origin of E-M183 in NW Africa.

High prevalence of carriers of variant c.1528G>C of HADHA gene causing long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) in the population of adult Kashubians from North Poland

Background/Objectives

The mitochondrial β-oxidation of fatty acids is a complex catabolic pathway. One of the enzymes of this pathway is the heterooctameric mitochondrial trifunctional protein (MTP), composed of four α- and β-subunits. Mutations in MTP genes (HADHA and HADHB), both located on chromosome 2p23, cause MTP deficiency, a rare autosomal recessive metabolic disorder characterized by decreased activity of MTP. The most common MTP mutation is long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency caused by the c.1528G>C (rs137852769, p.Glu510Gln) substitution in exon 15 of the HADHA gene.

Subjects/Methods

We analyzed the frequency of genetic variants in the HADHA gene in the adults of Kashubian origin from North Poland and compared this data in other Polish provinces.

Results

We found a significantly higher frequency of HDHA c.1528G>C (rs137852769, p.Glu510Gln) carriers among Kashubians (1/57) compared to subjects from other regions of Poland (1/187). We found higher frequency of c.652G>C (rs71441018, pVal218Leu) polymorphism in the HADHA gene within population of Silesia, southern Poland (1/107) compared to other regions.

Conclusion

Our study indicate described high frequency of c.1528G>C variant of HADHA gene in Kashubian population, suggesting the founder effect. For the first time we have found high frequency of rs71441018 in the South Poland Silesian population.

Updated 24-year trend of Type 1 diabetes incidence in children in Poland reveals a sinusoidal pattern and sustained increase

AIMS

To present the incidence trend for Type 1 diabetes in Polish children aged 0-14 years, updated using data collected during 2005-2012, and assess the reliability of the predictive model constructed previously using the 1989-2004 database.

METHODS

Children aged < 15 years with newly diagnosed Type 1 diabetes are recorded prospectively (EURODIAB criteria) in several regional registers in Poland. Age- and gender-standardized incidence rates for Type 1 diabetes were calculated per 100 000 persons/year. Incidence rates were analysed in terms of the dependency on age, gender, geographical region and population density. Incidence rate trends over time were modelled using generalized linear models.

RESULTS

The mean standardized incidence for 1989-2012 was 12.72 per 100 000 persons/year [95% confidence interval (CI), 11.35 to 14.21]. Over the 24-year observation period, the incidence increased from 5.36 to 22.74 per 100 000 persons/year. The lowest incidence rate was in children aged 0-4 years (8.35, 95% CI 7.27 to 9.57 per 100 000 persons/year). There was no difference between genders, or urban and rural regions. Incidence rates were higher in northern compared with southern Poland [14.04 (95% CI 12.59 to 15.63) vs. 11.94 (95% CI 10.62 to 13.39) per 100 000 persons/year]. The new data corrected the earlier predictive model by changing the estimates of some factors related to patient age, gender and their interactions with the remaining factors. The incidence rate shows periodic 5.33-year fluctuations. The periodicity component allows for a more accurate prediction of the incidence rate over time.

CONCLUSIONS

This cohort study reveals a sustained increase in Type 1 diabetes incidence in Polish children aged 0-14 years with regular, sinusoidal fluctuations and a slight levelling off in past few years. It is of concern that are the highest increases in incidence are found in children aged 0-4 years.

Analysis of the R1b-DF27 haplogroup shows that a large fraction of Iberian Y-chromosome lineages originated recently in situ

Haplogroup R1b-M269 comprises most Western European Y chromosomes; of its main branches, R1b-DF27 is by far the least known, and it appears to be highly prevalent only in Iberia. We have genotyped 1072 R1b-DF27 chromosomes for six additional SNPs and 17 Y-STRs in population samples from Spain, Portugal and France in order to further characterize this lineage and, in particular, to ascertain the time and place where it originated, as well as its subsequent dynamics. We found that R1b-DF27 is present in frequencies ~40% in Iberian populations and up to 70% in Basques, but it drops quickly to 6–20% in France. Overall, the age of R1b-DF27 is estimated at ~4,200 years ago, at the transition between the Neolithic and the Bronze Age, when the Y chromosome landscape of W Europe was thoroughly remodeled. In spite of its high frequency in Basques, Y-STR internal diversity of R1b-DF27 is lower there, and results in more recent age estimates; NE Iberia is the most likely place of origin of DF27. Subhaplogroup frequencies within R1b-DF27 are geographically structured, and show domains that are reminiscent of the pre-Roman Celtic/Iberian division, or of the medieval Christian kingdoms.

Forensic genetic analyses in isolated populations with examples of central European Valachs and Roma

Isolated populations present a constant threat to the correctness of forensic genetic casework. In this review article we present several examples of how analyzing samples from isolated populations can bias the results of the forensic statistics and analyses. We select our examples from isolated populations from central and southeastern Europe, namely the Valachs and the European Roma. We also provide the reader with general strategies and principles to improve the laboratory practice (best practice) and reporting of samples from supposedly isolated populations. These include reporting the precise population data used for computing the forensic statistics, using the appropriate θ correction factor for calculating allele frequencies, typing ancestry informative markers in samples of unknown or uncertain ethnicity and establishing ethnic-specific forensic databases.

Male Lineages in Brazil: Intercontinental Admixture and Stratification of the European Background

The non-recombining nature of the Y chromosome and the well-established phylogeny of Y-specific Single Nucleotide Polymorphisms (Y-SNPs) make them useful for defining haplogroups with high geographical specificity; therefore, they are more apt than the Y-STRs to detect population stratification in admixed populations from diverse continental origins. Different Y-SNP typing strategies have been described to address issues of population history and movements within geographic territories of interest. In this study, we investigated a set of 41 Y-SNPs in 1217 unrelated males from the five Brazilian geopolitical regions, aiming to disclose the genetic structure of male lineages in the country. A population comparison based on pairwise FST genetic distances did not reveal statistically significant differences in haplogroup frequency distributions among populations from the different regions. The genetic differences observed among regions were, however, consistent with the colonization history of the country. The sample from the Northern region presented the highest Native American ancestry (8.4%), whereas the more pronounced African contribution could be observed in the Northeastern population (15.1%). The Central-Western and Southern samples showed the higher European contributions (95.7% and 93.6%, respectively). The Southeastern region presented significant European (86.1%) and African (12.0%) contributions. The subtyping of the most frequent European lineage in Brazil (R1b1a-M269) allowed differences in the genetic European background of the five Brazilian regions to be investigated for the first time.

Y-Chromosomal Lineages of Latvians in the Context of the Genetic Variation of the Eastern-Baltic Region

Variations of the nonrecombining Y-chromosomal region were investigated in 159 unrelated Baltic-speaking ethnic Latvians from four different geographic regions, using 28 biallelic markers and 12 short tandem repeats. Eleven different haplogroups (hgs) were detected in a regionally homogeneous Latvian population, among which N1c, R1a, and I1 cover more than 85% of its paternal lineages. When compared its closest geographic neighbors, the composition of the Latvian Y-chromosomal gene pool was found to be very similar to those of Lithuanians and Estonians. Despite the comparable frequency distribution of hg N1c in Latvians and Lithuanians with the Finno-Ugric-speaking populations from the Eastern coast of the Baltic Sea, the observed differences in allelic variances of N1c haplotypes between these two groups are in concordance with the previously stated hypothesis of different dispersal ways of this lineage in the region. More than a third of Latvian paternal lineages belong specifically to a recently defined R1a-M558 hg, indicating an influence from a common source within Eastern Slavic populations on the formation of the present-day Latvian Y-chromosome gene pool.

Genetic Heritage of the Balto-Slavic Speaking Populations: A Synthesis of Autosomal, Mitochondrial and Y-Chromosomal Data

The Slavic branch of the Balto-Slavic sub-family of Indo-European languages underwent rapid divergence as a result of the spatial expansion of its speakers from Central-East Europe, in early medieval times. This expansion–mainly to East Europe and the northern Balkans–resulted in the incorporation of genetic components from numerous autochthonous populations into the Slavic gene pools. Here, we characterize genetic variation in all extant ethnic groups speaking Balto-Slavic languages by analyzing mitochondrial DNA (n = 6,876), Y-chromosomes (n = 6,079) and genome-wide SNP profiles (n = 296), within the context of other European populations. We also reassess the phylogeny of Slavic languages within the Balto-Slavic branch of Indo-European. We find that genetic distances among Balto-Slavic populations, based on autosomal and Y-chromosomal loci, show a high correlation (0.9) both with each other and with geography, but a slightly lower correlation (0.7) with mitochondrial DNA and linguistic affiliation. The data suggest that genetic diversity of the present-day Slavs was predominantly shaped in situ, and we detect two different substrata: ‘central-east European’ for West and East Slavs, and ‘south-east European’ for South Slavs. A pattern of distribution of segments identical by descent between groups of East-West and South Slavs suggests shared ancestry or a modest gene flow between those two groups, which might derive from the historic spread of Slavic people.

Y-chromosome diversity in Catalan surname samples: insights into surname origin and frequency

The biological behavior of the Y chromosome, which is paternally inherited, implies that males sharing the same surname may also share a similar Y chromosome. However, socio-cultural factors, such as polyphyletism, non-paternity, adoption, or matrilineal surname transmission, may prevent the joint transmission of the surname and the Y chromosome. By genotyping 17 Y-STRs and 68 SNPs in ~2500 male samples that each carried one of the 50 selected Catalan surnames, we could determine sets of descendants of a common ancestor, the population of origin of the common ancestor, and the date when such a common ancestor lived. Haplotype diversity was positively correlated with surname frequency, that is, rarer surnames showed the strongest signals of coancestry. Introgression rates of Y chromosomes into a surname by non-paternity, adoption, and transmission of the maternal surname were estimated at 1.5-2.6% per generation, with some local variation. Average ages for the founders of the surnames were estimated at ~500 years, suggesting a delay between the origin of surnames (twelfth and thirteenth centuries) and the systematization of their paternal transmission. We have found that, in general, a foreign etymology for a surname does not often result in a non-indigenous origin of surname founders; however, bearers of some surnames with an Arabic etymology show an excess of North African haplotypes. Finally, we estimate that surname prediction from a Y-chromosome haplotype, which may have interesting forensic applications, has a ~60% sensitivity but a 17% false discovery rate.

The place of Slovakian paternal diversity in the clinal European landscape

BACKGROUND

Several demographic events have been postulated to explain the contemporaneous structure of European genetic diversity. First, an initial settlement of the continent by anatomically modern humans; second, the re-settlement of northern latitudes after the Last Glacial Maximum; third, the demic diffusion of Neolithic farmers from the Near East; and, fourth, several historical events such as the Slavic migration.

AIM

The aim of this study was to provide a more integrated picture of male-specific genetic relationships of Slovakia within the broader pan-European genetic landscape.

SUBJECTS AND METHODS

This study analysed a new Y-chromosome data-set (156 individuals) for both SNP and STR polymorphisms in population samples from five different Slovakian localities.

RESULTS

It was found that the male diversity of Slovakia is embedded in the clinal pattern of the major R1a and R1b clades extending over the continent and a similar pattern of population structure is found with Y-specific SNP or STR variation.

CONCLUSION

The highly significant correlation between the results based on fast evolving STRs on one hand and slow evolving SNPs on the other hand suggests a recent timeframe for the settlement of the area.

Traces of medieval migrations in a socially stratified population from Northern Italy. Evidence from uniparental markers and deep-rooted pedigrees

Social and cultural factors had a critical role in determining the genetic structure of Europe. Therefore, socially stratified populations may help to focus on specific episodes of European demographic history. In this study, we use uniparental markers to analyse the genetic structure of Partecipanza in San Giovanni in Persiceto (Northern Italy), a peculiar institution whose origins date back to the Middle Ages and whose members form the patrilineal descent of a group of founder families. From a maternal point of view (mtDNA), Partecipanza is genetically homogeneous with the rest of the population. However, we observed a significant differentiation for Y-chromosomes. In addition, by comparing 17 Y-STR profiles with deep-rooted paternal pedigrees, we estimated a Y-STR mutation rate equal to 3.90 * 10(-3) mutations per STR per generation and an average generation duration time of 33.38 years. When we used these values for tentative dating, we estimated 1300-600 years ago for the origins of the Partecipanza. These results, together with a peculiar Y-chromosomal composition and historical evidence, suggest that Germanic populations (Lombards in particular) settled in the area during the Migration Period (400-800 AD, approximately) and may have had an important role in the foundation of this community.

The phylogenetic and geographic structure of Y-chromosome haplogroup R1a

R1a-M420 is one of the most widely spread Y-chromosome haplogroups; however, its substructure within Europe and Asia has remained poorly characterized. Using a panel of 16 244 male subjects from 126 populations sampled across Eurasia, we identified 2923 R1a-M420 Y-chromosomes and analyzed them to a highly granular phylogeographic resolution. Whole Y-chromosome sequence analysis of eight R1a and five R1b individuals suggests a divergence time of ∼25,000 (95% CI: 21,300-29,000) years ago and a coalescence time within R1a-M417 of ∼5800 (95% CI: 4800-6800) years. The spatial frequency distributions of R1a sub-haplogroups conclusively indicate two major groups, one found primarily in Europe and the other confined to Central and South Asia. Beyond the major European versus Asian dichotomy, we describe several younger sub-haplogroups. Based on spatial distributions and diversity patterns within the R1a-M420 clade, particularly rare basal branches detected primarily within Iran and eastern Turkey, we conclude that the initial episodes of haplogroup R1a diversification likely occurred in the vicinity of present-day Iran.

Northern Slavs from Serbia do not show a founder effect at autosomal and Y-chromosomal STRs and retain their paternal genetic heritage

Studies on Y-chromosomal markers revealed significant genetic differentiation between Southern and Northern (Western and Eastern) Slavic populations. The northern Serbian region of Vojvodina is inhabited by Southern Slavic Serbian majority and, inter alia, Western Slavic (Slovak) and Eastern Slavic (Ruthenian) minorities. In the study, 15 autosomal STR markers were analysed in unrelated Slovaks, Ruthenians and Serbs from northern Serbia and western Slovakia. Additionally, Slovak males from Serbia were genotyped for 17 Y-chromosomal STR loci. The results were compared to data available for other Slavic populations. Genetic distances for autosomal markers revealed homogeneity between Serbs from northern Serbia and Slovaks from western Slovakia and distinctiveness of Serbian Slovaks and Ruthenians. Y-STR variation showed a clear genetic departure of the Slovaks and Ruthenians inhabiting Vojvodina from their Serbian neighbours and genetic similarity to the Northern Slavic populations of Slovakia and Ukraine. Admixture estimates revealed negligible Serbian paternal ancestry in both Northern Slavic minorities of Vojvodina, providing evidence for their genetic isolation from the Serbian majority population. No reduction of genetic diversity at autosomal and Y-chromosomal markers was found, excluding genetic drift as a reason for differences observed at autosomal STRs. Analysis of molecular variance detected significant population stratification of autosomal and Y-chromosomal microsatellites in the three Slavic populations of northern Serbia, indicating necessity for separate databases used for estimations of frequencies of autosomal and Y-chromosomal STR profiles in forensic casework. Our results demonstrate that regarding Y-STR haplotypes, Serbian Slovaks and Ruthenians fit in the Eastern European metapopulation defined in the Y chromosome haplotype reference database.

Genome-wide and paternal diversity reveal a recent origin of human populations in North Africa

The geostrategic location of North Africa as a crossroad between three continents and as a stepping-stone outside Africa has evoked anthropological and genetic interest in this region. Numerous studies have described the genetic landscape of the human population in North Africa employing paternal, maternal, and biparental molecular markers. However, information from these markers which have different inheritance patterns has been mostly assessed independently, resulting in an incomplete description of the region. In this study, we analyze uniparental and genome-wide markers examining similarities or contrasts in the results and consequently provide a comprehensive description of the evolutionary history of North Africa populations. Our results show that both males and females in North Africa underwent a similar admixture history with slight differences in the proportions of admixture components. Consequently, genome-wide diversity show similar patterns with admixture tests suggesting North Africans are a mixture of ancestral populations related to current Africans and Eurasians with more affinity towards the out-of-Africa populations than to sub-Saharan Africans. We estimate from the paternal lineages that most North Africans emerged ∼15,000 years ago during the last glacial warming and that population splits started after the desiccation of the Sahara. Although most North Africans share a common admixture history, the Tunisian Berbers show long periods of genetic isolation and appear to have diverged from surrounding populations without subsequent mixture. On the other hand, continuous gene flow from the Middle East made Egyptians genetically closer to Eurasians than to other North Africans. We show that genetic diversity of today's North Africans mostly captures patterns from migrations post Last Glacial Maximum and therefore may be insufficient to inform on the initial population of the region during the Middle Paleolithic period.

Mutational analysis in podocin-associated hereditary nephrotic syndrome in Polish patients: founder effect in the Kashubian population

Hereditary nephrotic syndrome is caused by mutations in a number of different genes, the most common being NPHS2. The aim of the study was to identify the spectrum of NPHS2 mutations in Polish patients with the disease. A total of 141 children with steroid-resistant nephrotic syndrome (SRNS) were enrolled in the study. Mutational analysis included the entire coding sequence and intron boundaries of the NPHS2 gene. Restriction fragment length polymorphism (RFLP) and TaqMan genotyping assay were applied to detect selected NPHS2 sequence variants in 575 population-matched controls. Twenty patients (14 %) had homozygous or compound heterozygous NPHS2 mutations, the most frequent being c.1032delT found in 11 children and p.R138Q found in four patients. Carriers of the c.1032delT allele were exclusively found in the Pomeranian (Kashubian) region, suggesting a founder effect origin. The 14 % NPHS2 gene mutation detection rate is similar to that observed in other populations. The heterogeneity of mutations detected in the studied group confirms the requirement of genetic testing the entire NPHS2 coding sequence in Polish patients, with the exception of Kashubs, who should be initially screened for the c.1032delT deletion.