Y Chromosome and Mitochondrial DNA Characterization of Pasiegos, a Human Isolate from Cantabria (Spain)

Abstract

SummaryMitochondrial DNA sequences and Y chromosome haplotypes were characterized in Pasiegos, a human isolate from Cantabria, and compared with those of other Cantabrian and neighbouring Northern Spain populations. Cantabria appears to be a genetically heterogeneous community. Whereas Lebaniegos do not differ from their eastern Basque and western Asturian and Galician neighbours, Pasiegos and other non-Lebaniego Cantabrians show significant differences with all of them. Pasiegos are peculiar for their high frequencies of Y chromosomal markers (E-M81) with North African assignation, and Y chromosomal (R-SRY2627) and mtDNA (V, I, U5) markers related to northern European populations. This dual geographic contribution is more in agreement with the complex demographic history of this isolate, as opposed to recent drift effects. The high incidence in Cantabrians with pre-V and V mtDNA haplotypes, considered as a signal of Postglacial recolonization in Europe from south-western refugees, points to such refugees as a better candidate population than Basques for this expansion. However, this does not discount a conjoint recolonization.

Using mitochondrial DNA to test the hypothesis of a European post-glacial human recolonization from the Franco-Cantabrian refuge

“…It has been previously suggested that the Pasiegos are a complex human isolate. On the basis of their high frequency for the North-African Y-chromosome E-M81 haplogroup and a relative abundance of other Y-chromosome and mtDNA haplogroups, of typical northern European ascription, dual gene-flow influences were assumed to affect this isolate (Maca-Meyer et al, 2003). In this study, again, the high frequency of H4 and the absence of H3 resembles the haplogroup H profile found for Moroccan Berbers (Ennafaa et al, 2009).…”

“…However, this should now be considered as due to sampling errors because when sample sizes were increased in posterior analyses, V frequencies in the Basque Country dropped to 12.4% (Torroni et al, 2001) and 10.2% (Maca-Meyer et al, 2003). In this study, haplogroup V frequencies in the Cornice are at their peak in Cantabria (19%), dropping westwards to 5.6% in Asturias and to 3.8% in Galicia.…”

“…Excluding the highly divergent Pasiego isolate (Maca-Meyer et al, 2003), there are also significant differences between the Basque provinces or between Catalonia at the north-eastern edge and Galicia-Asturias in the northwest. In fact, when these results were represented in an multidimensional scaling plot (Figure 2), the Pasiegos and Spanish Basques from Guipuzcoa and Alava were the most outstanding outliers, also followed by samples from Catalonia and Galicia, the French Basque sample and the British samples from Cornwall and Wales.…”

The place of the Basques in the European Y-chromosome diversity landscape

“…The latter is the most widespread haplogroup of the E cluster in Iberia, reaching its highest frequencies both in southern and northern parts of the Iberian Peninsula. 9,26 Relationships among the Basque samples To explore the hypothesis that the Basques might not constitute a homogeneous population, 27,28 we tested the pairwise F ST values among the individual Basque samples. For the binary markers, after Bonferroni correction (a ¼ 0.008), the hypothesis of a single Basque population is rejected (Supplementary Information 3).…”

A CXCL2 tandem repeat promoter polymorphism is associated with susceptibility to severe sepsis in the Spanish population

“…However, it has been shown that both continental and Island populations have suffered from North African influences at different levels. [17][18][19][20][21] The Canary Islanders, the populations from Castilla and the southern Spanish populations from Andalusia have been reported to have the highest percentage of North African influences in Spain. 19,20 In order to meet power requirements (see Materials and methods) while preserving the homogeneity of the population, we included 179 unrelated patients, which met severe sepsis criteria, 22 from different Spanish localities with as similar as possible genetic backgrounds: Tenerife, one of the major islands of the Canarian Archipelago (a total of 64 patients) and different localities from Castilla (a total of 115 patients).…”