Population structure of modern-day Italians reveals patterns of ancient and archaic ancestries in Southern Europe.

European populations display low genetic differentiation as the result of long-term blending of their ancient founding ancestries. However, it is unclear how the combination of ancient ancestries related to early foragers, Neolithic farmers, and Bronze Age nomadic pastoralists can explain the distribution of genetic variation across Europe. Populations in natural crossroads like the Italian peninsula are expected to recapitulate the continental diversity, but have been systematically understudied. Here, we characterize the ancestry profiles of Italian populations using a genome-wide dataset representative of modern and ancient samples from across Italy, Europe, and the rest of the world. Italian genomes capture several ancient signatures, including a non-steppe contribution derived ultimately from the Caucasus. Differences in ancestry composition, as the result of migration and admixture, have generated in Italy the largest degree of population structure detected so far in the continent, as well as shaping the amount of Neanderthal DNA in modern-day populations.

The Arabo-Islamic migrations in Madagascar: first genetic study of the GM system in three Malagasy populations.

The Antemoro are an ethnic group from the southeast coast of Madagascar who claims an Arab origin. Cultural signatures of an Arabo-Islamic influence have been found in this region. Nevertheless, their origins are very contentious. Through this study, we want to determine whether this ethnic group had a particular GM profile that differentiated it from other Malagasy populations, and whether there were detectable genetic traces of the Arabo-Islamic migration. The Gm polymorphisms of IgG immunoglobulins was analysed in a population of Antemoro (N = 85), two other Malagasy populations from northern Fiherena (N = 82) and southern Fiherena (N = 50) and in a Comorian population (N = 171). This last group was used to enlarge the database for genetic comparisons. Results revealed significant contributions from Africa (60%, 0.092 ≤F(ST) ≤ 0.280) and Southeast Asia (40%, 0.043 ≤ F(ST) ≤ 0.590) to the Antemoro genetic pool. No direct genetic relationships with the Middle East. These results bring new insights into the population history of Madagascar.

The Andalusian population from Huelva reveals a high diversification of Y-DNA paternal lineages from haplogroup E: Identifying human male movements within the Mediterranean space.

BACKGROUND: Gene flow among human populations is generally interpreted in terms of complex patterns, with the observed gene frequencies being the consequence of the entire genetic and demographic histories of the population. AIMS: This study performs a high-resolution analysis of the Y-chromosome haplogroup E in Western Andalusians (Huelva province). The genetic information presented here provides new insights into migration processes that took place throughout the Mediterranean space and tries to evaluate its impact on the current genetic composition of the most southwestern population of Spain. SUBJECTS AND METHODS: 167 unrelated males were previously typed for the presence/absence of the Y-chromosome Alu polymorphism (YAP). The group of YAP (+) Andalusians was genotyped for 16 Y-SNPs and also characterized for 16 Y-STR loci. RESULTS: The distribution of E-M81 haplogroup, a Berber marker, was found at a frequency of 3% in our sample. The distribution of M81 frequencies in Iberia seems to be not concordant with the regions where Islamic rule was most intense and long-lasting. The study also showed that most of M78 derived allele (6.6%) led to the V13* subhaplogroup. We also found the most basal and rare paragroup M78* and others with V12 and V65 mutations. The lineage defined by M34 mutation, which is quite frequent in Jews, was detected as well. CONCLUSIONS: The haplogroup E among Western Andalusians revealed a complex admixture of genetic markers from the Mediterranean space, with interesting signatures of populations from the Middle East and the Balkan Peninsula and a surprisingly low influence by Berber populations compared to other areas of the Iberian Peninsula.

The complex and diversified mitochondrial gene pool of Berber populations.

The mitochondrial DNA variation of 295 Berber-speakers from Morocco (Asni, Bouhria and Figuig) and the Egyptian oasis of Siwa was evaluated by sequencing a portion of the control region (including HVS-I and part of HVS-II) and surveying haplogroup-specific coding region markers. Our findings show that the Berber mitochondrial pool is characterized by an overall high frequency of Western Eurasian haplogroups, a somehow lower frequency of sub-Saharan L lineages, and a significant (but differential) presence of North African haplogroups U6 and M1, thus occupying an intermediate position between European and sub-Saharan populations in PCA analysis. A clear and significant genetic differentiation between the Berbers from Maghreb and Egyptian Berbers was also observed. The first are related to European populations as shown by haplogroup H1 and V frequencies, whereas the latter share more affinities with East African and Nile Valley populations as indicated by the high frequency of M1 and the presence of L0a1, L3i, L4*, and L4b2 lineages. Moreover, haplogroup U6 was not observed in Siwa. We conclude that the origins and maternal diversity of Berber populations are old and complex, and these communities bear genetic characteristics resulting from various events of gene flow with surrounding and migrating populations.

Uniparental (mtDNA, Y-chromosome) polymorphisms in French Guiana and two related populations--implications for the region's colonization.

Blood samples collected in four Amerindian French Guiana populations (Palikur, Emerillon, Wayampi and Kali'na) in the early 1980s were screened for selected mtDNA and Y-chromosome length polymorphisms, and sequenced for the mtDNA hypervariable segment I (HVS-I). In addition, two other Amerindian populations (Apalaí and Matsiguenga) were examined for the same markers to establish the genetic relationships in the area. Strong dissimilarities were observed in the distribution of the founding Amerindian haplogroups, and significant p-values were obtained from F(ST) genetic distances. Interpopulation similarities occurred mainly due to geography. The Palikur did not show obvious genetic similarity to the Matsiguenga, who speak the same language and live in a region from where they could have migrated to French Guiana. The African-origin admixture observed in the Kali'na probably derives from historical contacts they had with the Bushinengue (Noir Marron), a group of escaped slaves who now lead independent lives in a nearby region. This analysis has identified significant clues about the Amerindian peopling of the North-East Amazonian region.

Estimating sex-specific processes in human populations: Are XY-homologous markers an effective tool?

Homologous markers on the sex-specific regions of the X- and Y-chromosomes are differentially inherited through males and females, and have similar molecular characteristics. They may therefore be useful as a complement to the comparison of mtDNA and Y-chromosomal haplotypes for estimating sex-specific processes shaping human population structure. To test this idea, we analyzed XY-homologous microsatellite diversity in 33 human populations from Africa, Asia and Europe. Interpopulation comparisons suggest that the generally discordant pattern of genetic variation observed for X- and Y-linked markers could be an outcome of sex-specific migration processes (m(females)/m(males) approximately 3) or sex-specific demographic processes (N(females)/N(males) approximately 11) or a combination of both. However, intrapopulation diversity estimated by the X/Y ratio Watterson estimator (theta(H(Y))/theta(H(X))) suggests that the scenarios required to explain the global genetic variation of XY-homologous markers are many and complex, and that the sex-specific processes (effective population size and migration rate) shaping human population structures are likely to be specific to each population under study. XY-homologous markers provide an insight into the genuine complexity of sex-specific processes, and their further exploitation in human population studies seems worthwhile.

Study of GM immunoglobulin allotypic system in Berbers and Arabs from Morocco.

The GM immunoglobulin allotype polymorphism was investigated in four Moroccan populations: three Berber groups from Khenifra (Middle Atlas), Amizmiz (High Atlas), and Bouhria (Beni Snassen) and one Arabic-speaking sample from the Doukkala area (Abda, Chaouia, Doukkali, and Tadla districts in south-central Morocco). In order to characterize the genetic relationships between the populations, our results were compared with those obtained for other North African groups (from Morocco, Algeria, Tunisia, and Niger) and for Middle-East Africans, sub-Saharans, and Southwest Europeans. Based on GM haplotype frequencies, Factorial Correspondence Analyses, F(ST) significance testing, and hierarchical analyses of variance were performed. Our results reveal that Moroccan populations have heterogeneous GM profiles with high frequencies of GM haplotypes in Europeans (from 76% for Doukkala to 88% for Bouhria) and relatively high frequencies of GM haplotypes in sub-Saharans (from 11% for Bouhria to 23% for Amizmiz). The genetic diversity observed among Moroccans is not significantly correlated with either geographic or linguistic differentiation. In spite of their cultural and historical differentiation, we did not discover any significant genetic differences between Berbers and Arabic-speakers from Morocco. However, when large geographical areas are considered, our population samples are integrated in the North African GM variation, significantly distant from sub-Saharan groups but with a close relationship with Southwest European populations.

Genetic position of Andalusians from Huelva in relation to other European and North African populations: a study based on GM and KM allotypes.

An understanding of population relationships in the Mediterranean region is crucial to the reconstruction of recent human evolution. Andalusia, the most southern region of Spain, has been continuously and densely occupied since ancient times and has a rich history of contacts with many different Mediterranean populations. Thus, to understand the Mediterranean peopling process, investigators should analyze the population relationships between the Iberian peninsula and northern Africa based on an assessment of genetic diversity that takes Andalusia into consideration. The aim of this study was to address the extent of genetic variation in the Iberian peninsula between its geographic extremes (Huelva and the Basque area) and to explain the intensity of the phylogenetic relationships between Andalusians and other neighboring populations, such as those from North Africa. We present, for the first time, results on allotype markers (GM and KM) of human immunoglobulins in the Andalusian population from Huelva. The most frequent GM haplotypes in Andalusia correspond to those that are also the most common in Europe. A sub-Saharan haplotype was found at a relatively high frequency compared to other Iberian samples, and a North Asian marker did not reach polymorphic frequencies in the study sample. A hierarchical cluster analysis based on the first two principal components (94.1% of the total genetic variance) revealed an interesting geographic structure for the 49 populations selected from the literature. The Huelva sample showed a central position in the multivariate space--despite being geographically located at one of the extremes of the Mediterranean basin--and clustered with most Western European populations. Western Europe and Eastern Europe (the latter group paradoxically including Italy and the major islands of the western Mediterranean) were differentiated. North African populations were grouped in two clusters that did not separate either Arabs and Berbers or their present-day countries. Analysis of immunoglobulin allotype markers shows that gene flow among human populations should generally be interpreted in terms of complex patterns, with the observed frequencies being the consequence of the entire genetic and demographic history of the population. Single historical events rarely determine gene frequencies in large human populations. Analysis of the GM system has shown that the Andalusian population from Huelva, as a result of its complex history, is not simply an outstanding part of the Mediterranean world but rather the genetic center of gravity of that world.

An unexpected wide population variation of the G1733A polymorphism of the androgen receptor gene: data on the Mediterranean region.

The androgen receptor (AR) has been proposed as a candidate gene for several cancers (breast, prostate, uterine endometrium, colon, and esophagus). Ethnicity is considered an associated risk factor for some of these cancers. Several case-control genetic studies have been focused in samples of the main ethnic groups, but little is known about the distribution of risk polymorphisms in current populations with accurate ethnic and/or geographic origins. The A allele of the G1733A polymorphism of the AR gene has been associated with increased risk of prostate cancer. We provide data from this marker in 12 samples from 7 Mediterranean countries such as Spain, Italy (Sardinia), Greece, Turkey, Morocco, Algeria, and Egypt. A sample from Ivory Coast has also been analyzed. The A allele distribution shows a frequency in the Ivory Coast population (65.17%) that contrasts with the low values found in Northern Mediterraneans (mean average value of 13.98%). North African populations present two-times higher frequencies (average value of 27.19%) than Europeans. The wide population variation range found for the A allele strengthens the potential interest of further screening as a baseline to the design of future preventive and population health programs.

Allele variation of DYS19 and Y-Alu insertion (YAP) polymorphisms in Basques: an insight into the peopling of Europe and the Mediterranean region.

Two Y-chromosome DNA polymorphisms, the DYS19 microsatellite and the YAP (at locus DYS287), were tested in males from two autochthonous Basque populations from France and northern Navarre (Spain). The results are compared to those obtained for the same genetic markers in 32 populations from Europe, northern Africa, and western Asia. The high predominance of the DYS19*11 (190-base-pair) allele in Basques indicates that their genetic diversity for microsatellite DYS19 is around half that observed in Europeans, North Africans, and western Asians. The Y-Alu insertion (YAP+) was not detected in the Basque samples. This study attempts to throw some light on the importance of historically recent migratory movements, the main corridors of gene flow, and demographic sizes and their variations in shaping gene frequency patterns in contemporary human populations, particularly in the Mediterranean region. Historical processes may have had more significant effects on the genetic make-up of current human populations than those of prehistoric times.

Microsatellite DNA markers from HLA region (D6S105, D6S265 and TNFa) in autochthonous Basques from Northern Navarre (Spain).

BACKGROUND: The extent of the genetic polymorphism of the HLA complex is becoming well characterized in Basque population and their subpopulations. This level of knowledge mainly concerns HLA class I loci. However, Basque population surveys dealing with HLA class II genes and/or microsatellites in the HLA region are still very scarce. AIM: The population genetics of three highly polymorphic short tandem repeat (STR) loci, D6S105, D6S265 and TNFa, from HLA region has been analysed in autochthonous (indigenous) Basques from Northern Navarre (Spain). The same blood samples have been typed for HLA class II genes from DQ/DR/DP regions and some findings from that information can be found therein. SUBJECTS AND METHODS: Blood samples were taken from 107 unrelated autochthonous Basques from Northern Navarre. The criterion used to define Northern Navarrese identity was that of three generations of Basque surnames and birthplaces. RESULTS: The main features observed in Navarrese Basques were the rather high frequencies of alleles D6S105*4 and D6S265*7. A novel allele has been detected at the D6S265 locus (13: 145 bp). The most frequent haplotype was D6S105*8-D6S265*4 with a highly significant linkage disequilibrium being presented. The high frequency of allele TNFa*1 in Basques is noteworthy and this characteristic is not shared by other European populations, where TNFa*1 is absent or shows negligible values. The multidimensional scaling analysis (MDS) for TNFa allele frequencies has shown a high variability among populations and that alleles TNFa*1 (F(ST) = 0.0615) and TNFa*12 (F(ST) = 0.0424) seem to have significant influence over the spatial population configuration. TNFa*2 showed the lowest FST value (0.0077) because of its conspicuous homogeneous distribution all over the European populations. CONCLUSIONS: Findings shown here on HLA microsatellites and their relationships with other HLA class I and class II genes in Basques can be helpful for those studies mainly addressed at detecting associations between HLA genes and diseases in the Basque area as a whole, and particularly in its autochthonous population, settled there since remote times.

Molecular polymorphism of O alleles in five populations of different ethnic origins.

Sequences of exons 6 and 7 of the O allele of the ABO gene were studied in 317 individuals of the O phenotype from five different ethnic groups (Basques, Berbers, Akans from the Ivory Coast, and Amerindians: Cayapas from Ecuador and Aymaras from Bolivia). Twenty-one O alleles were characterized, among which 9 differed from all O alleles reported to date. The nine alleles differed from either the O01 allele (four out of nine) or O02 allele (five out of nine) by one to three point mutations. The number of different O alleles in population samples varied greatly: the highest number (13) was observed in Akans, and the lowest (5) in Amerindians. Some rare alleles previously reported by others at low frequencies were found with high frequencies in the Akans. The results also revealed a decreasing frequency of Ov7 alleles from south to north (Akans, Berbers, Basques). Berbers and Basques share two rare alleles, Ov6 and O03, which were not encountered in the other populations studied here.

A worldwide analysis of AG molecular diversity inferred from serology.

Ten population samples from different geographic origins were tested serologically for the AG polymorphism of human beta-lipoproteins. Their haplotype frequencies were used with previously published data to perform a wide analysis of AG genetic differentiations throughout the world. Coancestry coefficients were computed from weighted F(ST)s among populations by using a matrix of molecular distances among AG haplotypes, which is here determined on the basis of DNA studies. Coancestry coefficients derived from unweighted F(ST)s and more classical Prevosti distances were computed on the same data and used for a comparison. In all cases a highly significant correlation was found between genetics and geography on a worldwide scale, while the significance of the correlation with linguistics differed. A test of significance of the pairwise F(ST)s among populations also gave different results depending on whether the molecular distance matrix among AG haplotypes was included. Globally, this study shows that in spite of being highly significantly correlated to each other, different genetic distance measures can lead to different interpretations of the same data set. Moreover, the elucidation of the molecular models related to the presently known serological polymorphisms may represent an additional tool for analyzing such polymorphisms in human population genetics studies.

Gm and Km alleles in two Spanish Pyrenean populations (Andorra and Pallars Sobirà): a review of Gm variation in the Western Mediterranean basin.

Two Spanish eastern Pyrenean populations, Andorra and Pallars Sobirà, have been tested for G1m(1,2,3,17), G2m(23), G3m(5,6,10,11,13,14,15,16,21,24,28) and Km(1) immunoglobulin allotypes. Km allele and Gm haplotype frequencies in both samples fit well into the Western Mediterranean and, more strictly, Pyrenean ranges with some peculiarities: Andorra showed an elevated frequency (14.7%) of the typical Asian and European Gm21,28;1,2,17;. haplotype, while Pallars Sobirà was characterized by high values (3.7%) of Gm5*;1,17;., a typical sub-Saharan Gm haplotype. Gm diversity assessed through genetic distance and variance analyses revealed a significant geographic partition (4.3%) of Mediterraneans among south, north-east, and north-west groups. It is interesting to note the relatively low genetic variance (2.1%) found between south and north-western Mediterraneans that could reflect ancient population relationships. More locally, genetic boundaries and diversity analyses failed to indicate any geographic pattern and/or genetic differentiation related with the political border in the Pyrenees. The present pattern of variation in this area is probably the result of genetic isolation processes, in addition to some specific demographic phenomena, in the Pyrenean valleys.

A study of Gm allotypes and immunoglobulin heavy gamma IGHG genes in Berbers, Arabs and sub-Saharan Africans from Jerba Island, Tunisia.

The Gm polymorphism of human IgG immunoglobulins was investigated in three different ethnic groups--Arabs, Berbers and 'dark-skinned people'--on Jerba Island, Tunisia. The genetic relationships among these groups and several populations from North Africa, sub-Saharan Africa, west Asia and Europe were analysed by principal coordinate analysis, Fst significance testing, and analysis of molecular variance based on haplotype frequencies. The results revealed a non-significant genetic differentiation between Arabs and Berbers from Jerba. However, the Jerbian population of sub-Saharan African origin was close to Ethiopians. Gene flow among the three Jerbian populations, as well as an East African origin of the dark-skinned individuals, is proposed to account for the observed genetic pattern. However, the genetic diversity observed among the different Tunisian populations did not show any significant correlation with either geographic or linguistic differentiation. A preliminary analysis of the restriction fragment length polymorphism of the IGHG genes in Arabs and Berbers from Jerba confirmed the close genetic relationship between the two populations. However, it also indicated a lower level of genetic diversity in the Berbers, which may be explained by more rapid genetic drift due to longer isolation on the island.

The genetic position of the autochthonous subpopulation of Northern Navarre (Spain) in relation to other basque subpopulations. A study based on GM and KM immunoglobulin allotypes.

GM and KM immunoglobulin (Ig) allotypes were tested in 118 autochthonous Basques from northern Navarre. The results are compared to those obtained for the same genetic markers in 6 other Basque subpopulations, 3 from Spain (Guipúzcoa, Vizcaya, and Alava) and 3 from France: Macaye, Saint-Jean Pied de Port, and Mauleon. The northern Navarrese appear genetically closer to the Alava and Saint-Jean Pied de Port subpopulations. The Basques present 3 GM haplotypes that are uncommon in Caucasian populations, suggesting that they have not been completely isolated either from Asian or African populations. The GM*1,17 23' 10,11,13,15,16 north Asian haplotype was probably the first to be introduced into the Basque area. The GM*1,17 23' 5* haplotype, considered an African genetic marker although also detected in Central Asia, would have reached the Iberian Peninsula through consecutive historic migrations from North Africa. The rare haplotype GM*1,17 23 21,28 results probably from a genetic recombination or crossing-over between the 2 common haplotypes GM*1, 17 23' 21,28 and GM*3 23 5*. It is also found with a low frequency in other neighboring regions and countries; but the possibility of its having been introduced through the main passage connecting western France and Spain during the Roman Empire and Middle Ages cannot be ruled out.

HLA-Gm/kappam interaction in sarcoidosis. Suggestions for a complex genetic structure.

The aetiology of sarcoidosis is still unknown. Environmental exposures are believed to interact with genetic factors in determining the pattern of sarcoidosis presentation, progression and prognosis. The frequency of serological polymorphism of immunoglobulin G heavy chain (Gm) and kappa light chain (kappam) markers in 107 patients with biopsy-proven sarcoidosis and in 227 controls, and their interactions with histocompatibility leukocyte antigen (HLA) class I, II, and III markers, were studied. A "protective" effect of the Gm(3 5*) phenotype in the sarcoid group versus controls (p-value for number of specificities tested (p(c))=0.05, odds ratio 0.15) and a reduced frequency of Gm(3 23 5*) in patients with advanced chest radiographic stage (Chi-squared (two degrees of freedom)(chi2(2df) 17.61, p(c)=0.0058) were observed. With reference to epistatic interactions, the combination Gm(3 23 5*)/BfS had a "protective" effect towards stage II (chi2(2dt) 13.86, p(c)=0.043). Finally, correspondence analysis defined two clusters: HLA-DR4, C4BQ0, Gm(1, 3, 17 23 5*, 21, 28) and BfF associated with stage II, and HLA-DR3, C4AQ0, kappam(1) and Gm(3 23 5*) associated with stage I. These data further support the hypothesis that sarcoidosis results from an interplay of environmental factors and genes, each contributing to the susceptibility/resistance to and/or the clinical heterogeneity of the disease. In addition, these data provide the first evidence of an interaction between immunoglobulin G heavy chain/kappa light chain markers and histocompatibility leukocyte antigen class III genes in a disease.

GM, KM immunoglobulin allotypes and other serum genetic markers (HP, GC, PI, and TF) among South American populations living at different altitudes (Jujuy Province, Argentina): admixture estimates.

A total of 154 individuals belonging to three populations located at different altitude levels in northwest Argentina (San Salvador de Jujuy, 1,200 m; Tilcara, 2,500 m; Abra Pampa, 3,500 m) were studied for the GM, KM, HP, GC, PI and TF genetic systems. Individuals were selected on the basis of ethnocultural affiliation. Gene frequency values were found to be comparable to those reported for other South American populations. The populations studied showed a close genetic identity and an absence of interpopulation heterogeneity. Distribution of the GM phenotypes and haplotypes corresponds to historical data on human settlements in Jujuy Province. The presence of some alleles and the anthropological significance of the allele distribution are discussed, as are the effects of the admixture with Africans and Spaniards. The genetic pattern appears to be the result of a varying admixture due to the genetic isolation in populations located at various altitude levels.

Genetic markers of immunoglobulins and diabetes mellitus in the multiracial population of New Caledonia. The CALDIA Study Group.

GM and KM immunoglobulin allotypes, which are the markers, respectively, of the constant parts of the heavy and the light chains of the IgG1, IgG2 and IgG3 subclasses, have been analysed in diabetic mellitus patients and controls living in New Caledonia. We tested 40 Europeans, 256 Melanesians and 44 Polynesians, as well as their 340 matched controls, in order to search for a genetic susceptibility at those polymorphic loci. All the subjects were tested for G1M (1, 2, 3, 17), G2M (23), G3M (5, 6, 10, 11, 13, 14, 15, 16, 21, 24, 28) and KM (1) by the classical hemagglutination method. The frequencies of GM haplotypes and KM alleles have been estimated by a maximum likelihood method. The results are in favour of no influence of the GM and KM loci. The prevalence of diabetes mellitus varies in the populations of New Caledonia: Polynesians are at much higher risk than Melanesians or Europeans. The GM haplotype distribution differs among ethnic groups; so they provide a useful marker to measure genetic admixture. The higher prevalence of diabetes observed among New Caledonians of European origin compared to the prevalence in Europe may be explained by genetic admixture with neighbouring Pacific populations, notably Polynesians (Asian haplotypes are present at a frequency of 9.4%). So, the genetic admixture should be measured in any genetic epidemiological study.

Gel test assay for IgG subclass detection by GM typing: application to hemolytic disease of the newborn.

The gel test assay was evaluated for IgG subclass detection by GM typing of antibodies and compared to the classical inhibition agglutination method on slides or microtiter plates. We used a panel of 5 murine monoclonal antibodies directed against G1M(1), G1M(3), G1M(17), G2M(23), and G3M(21) and 1 human polyclonal anti-G3M(5) antibody. Eleven polyclonal antisera (of immunized women) directed against red blood cells were tested for the GM allotypes carried by their alloantibodies. We controlled the specificity of the gel test reaction using a panel of anti-RH(D) monoclonal antibodies. All reagents exhibited a good reactivity and specificity. They can be used for routine typing. The gel test assay for IgG subclass detection is a specific, simple, and low-cost technique for the detection and management of severe forms of diseases in alloimmunized pregnancies.