Principal component analysis of gene frequencies and the origin of Basques

Calafell, Francesc; Bertranpetit, Jaume

doi:10.1002/ajpa.1330930205

Cited by 106 publications

(65 citation statements)

References 17 publications

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“…One possible explanation for this effect is that the historical evidence for the timing of the establishment of the Sorbs (B9 th century AD) suggests a relatively recent origin in contrast to the potentially much more ancient Sardinian (at least 5000 years 32 ) and Basque populations (at least 18 000 years 33 ). Topography may also be relevant in the fact that Sardinians are isolated on an island and Basque live in a mountainous region.…”

Section: Discussionmentioning

confidence: 99%

Genetic variation in the Sorbs of eastern Germany in the context of broader European genetic diversity

et al. 2011

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Population isolates have long been of interest to genetic epidemiologists because of their potential to increase power to detect disease-causing genetic variants. The Sorbs of Germany are considered as cultural and linguistic isolates and have recently been the focus of disease association mapping efforts. They are thought to have settled in their present location in eastern Germany after a westward migration from a largely Slavic-speaking territory during the Middle Ages. To examine Sorbian genetic diversity within the context of other European populations, we analyzed genotype data for over 30 000 autosomal single-nucleotide polymorphisms from over 200 Sorbs individuals. We compare the Sorbs with other European individuals, including samples from population isolates. Despite their geographical proximity to German speakers, the Sorbs showed greatest genetic similarity to Polish and Czech individuals, consistent with the linguistic proximity of Sorbian to other West Slavic languages. The Sorbs also showed evidence of subtle levels of genetic isolation in comparison with samples from non-isolated European populations. The level of genetic isolation was less than that observed for the Sardinians and French Basque, who were clear outliers on multiple measures of isolation. The finding of the Sorbs as only a minor genetic isolate demonstrates the need to genetically characterize putative population isolates, as they possess a wide range of levels of isolation because of their different demographic histories.

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Section: Discussionmentioning

confidence: 99%

Genetic variation in the Sorbs of eastern Germany in the context of broader European genetic diversity

et al. 2011

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“…The samples were from unrelated individuals of both genders, born and resident in their countries of origin, as their relatives had been for at least three generations. Basque, Corsican, and Sardinian samples were analysed separately from Spanish, French, and Italian samples, because of their genetic peculiarities (Calafell and Bertranpetit 1994;Varesi et al 2000;Vona 1997). …”

Section: Methodsmentioning

confidence: 99%

Human CHIT1 gene distribution: new data from Mediterranean and European populations

et al. 2006

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A 24 bp duplication in the CHIT1 gene (H allele) is associated with a deficiency in the activity of chitotriosidase, an enzyme with the capability to hydrolyse chitin. A recent study in European and two sub-Saharan populations suggested a relationship between the presence of the mutation, improved environmental conditions, and the disappearance of parasitic diseases, including Plasmodium falciparum malaria. This result was not supported by the high frequency of the 24 bp duplication in a sample from Taiwan, an area with high malaria endemicity until 40 years ago. In this study, we analysed the frequency variability of the H allele in Mediterranean populations and its internal variability in Sardinia (Italy) with respect to malaria, which had been endemic on the island until its eradication during [1946][1947][1948][1949][1950]. The pattern of H frequency distributions is not consistent with the hypothesis of selective pressures acting on CHIT1 gene. The Moran's index coefficient and correlogram seem to indicate, indeed, that allele distribution was determined by random factors. The pattern of frequency distribution suggests a possible Asiatic origin of the H allele, but it could be possible also that the mutant allele had diffused out of Africa, and was subsequently lost from African populations.

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“…The most outstanding feature in the west Mediterranean genetic landscape is the outlier position of Sardinians and Basques shown by classical genetic markers (Cavalli-Sforza et al 1994;Calafell & Bertranpetit 1994;Cappello et al 1996) and Y-chromosome polymorphisms (Caglià et al 1997;Scozzari et al 2001;Bosch et al 2001), although not so pronounced in the Basques. Nevertheless, mtDNA data reveals no differences between these two populations and the rest of European populations.…”

Section: Sw European Mtdna Landscapementioning

confidence: 99%

Joining the Pillars of Hercules: mtDNA Sequences Show Multidirectional Gene Flow in the Western Mediterranean

Plaza

Calafell

Helal

et al. 2003

Annals of Human Genetics

122

115

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SummaryPhylogenetic analysis of mitochondrial DNA (mtDNA) performed in Western Mediterranean populations has shown that both shores share a common set of mtDNA haplogroups already found in Europe and the Middle East. Principal co-ordinates of genetic distances and principal components analyses based on the haplotype frequencies show that the main genetic difference is attributed to the higher frequency of sub-Saharan L haplogroups in NW Africa, showing some gene flow across the Sahara desert, with a major impact in the southern populations of NW Africa. The AMOVA demonstrates that SW European populations are highly homogeneous whereas NW African populations display a more heterogeneous genetic pattern, due to an east-west differentiation as a result of gene flow coming from the East. Despite the shared haplogroups found in both areas, the European V and the NW African U6 haplogroups reveal the traces of the Mediterranean Sea permeability to female migrations, and allowed for determination and quantification of the genetic contribution of both shores to the genetic landscape of the geographic area.Comparison of mtDNA data with autosomal markers and Y-chromosome lineages, analysed in the same populations, shows a congruent pattern, although female-mediated gene flow seems to have been more intense than male-mediated gene flow.

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Principal component analysis of gene frequencies and the origin of Basques

Cited by 106 publications

References 17 publications

Genetic variation in the Sorbs of eastern Germany in the context of broader European genetic diversity

Genetic variation in the Sorbs of eastern Germany in the context of broader European genetic diversity

Human CHIT1 gene distribution: new data from Mediterranean and European populations

Joining the Pillars of Hercules: mtDNA Sequences Show Multidirectional Gene Flow in the Western Mediterranean

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