Immunoglobulin allotypes (GM and KM) in Basques from Spain: approach to the origin of the Basque population.
ABSTRACT GM and KM immunoglobulin (Ig) allotypes have been tested in 310 autochthonous Basques from the three subpopulations of Vizcaya, Guipúzcoa, and Alava, Spain. They are compared with allotypes occurring in autochthonous French Basques, some Pyrenean subpopulations in France, and European populations. The analysis suggests that the Basque subpopulations show noticeable genetic distances between them and with other European populations. The genetic similarity between Basques and European populations is greater in the Basques from France than in the Basques from Spain. The genetic distances between Basque subpopulations in Spain fit well with the different historical levels of the spatial implantation of the Basque language. Guipúzcoa, the Basque province with the highest number of Basque-speaking people, shows the most genetic distinctiveness. The main underlying cause of this spatial genetic pattern seems to be admixture with surrounding populations. Our results do not support the hypothesis that Basques are a relict population of ancient Europeans. They might be a consequence of the colonization of the Basque area by a long-distance migrating group, probably a small Neolithic North Caucasian population that introduced agriculture in the region. They experienced early, rapid demographic growth, and they did not breed with the few hunter-gatherers wandering throughout the area. The North Caucasian migrants could have admixed with North Asian groups dating from many centuries before. Furthermore, Basques present polymorphic frequencies of a common African haplotype, suggesting that they have not been completely isolated from populations of Africa. However, another focus of the African haplotype has been detected in Central Asia, and the Basque frequencies alternatively might be due to North Asian groups.
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ABSTRACT: This study examines the genetic variation in Basque Y chromosome lineages using data on 12 Y-short tandem repeat (STR) loci in a sample of 158 males from four Basque provinces of Spain (Alava, Vizcaya, Guipuzcoa, and Navarre). As reported in previous studies, the Basques are characterized by high frequencies of haplogroup R1b (83%). AMOVA analysis demonstrates genetic homogeneity, with a small but significant amount of genetic structure between provinces (Y-short tandem repeat loci STRs: 1.71%, p = 0.0369). Gene and haplotype diversity levels in the Basque population are on the low end of the European distribution (gene diversity: 0.4268; haplotype diversity: 0.9421). Post-Neolithic contribution to the paternal Basque gene pool was estimated by measuring the proportion of those haplogroups with a Time to Most Recent Common Ancestor (TMRCA) previously dated either prior (R1b, I2a2) or subsequent to (E1b1b, G2a, J2a) the Neolithic. Based on these estimates, the Basque provinces show varying degrees of post-Neolithic contribution in the paternal lineages (10.9% in the combined sample).Human Biology 08/2011; · 1.31 Impact Factor
Article: Genetic position of Andalusians from Huelva in relation to other European and North African populations: a study based on GM and KM allotypes.[show abstract] [hide abstract]
ABSTRACT: 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.Human Biology 01/2007; 78(6):663-79. · 1.31 Impact Factor
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ABSTRACT: We have characterized 68 unrelated Basque individuals from Vizcaya, Spain, for 13 tetrameric short tandem repeat (STR) loci: CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, TH01, TPOX, and VWA. Interpopulational analyses were also performed for 21 European and North African population data sets for nine of the STRs typed in the Basque sample. Heterozygosity values for the Vizcayan Basques were found to be high, ranging from 0.662 to 0.882, and none of the STR loci significantly deviated from Hardy-Weinberg equilibrium. Based on the comparative population data set, the average G(ST) score is 0.7%, indicating a low degree of genetic differentiation. However, neighbor-joining trees and multidimensional-scaling plots of D(A) genetic distances indicate that the Vizcayan Basques are an outlier relative to both neighboring Iberians and North African populations.Human Biology 11/2006; 78(5):599-618. · 1.31 Impact Factor