lunes, 18 de julio de 2011

R1b frequencies in Spain and Europe

The paper from Belareseque et al. 2010 gives us new percentages of R1b1b2 from different countries of Europe, as we can see in the table below. There is also a map of frequencies. As we can see again, Spain has among the highest percentages of Europe, especially the Spanish Basques, with 87.1 %, second most in Europe after Wales with 92.3 %.

Here are the levels for the regions of Spain :
  • Spain Basques........................87.1 %
  • Catalonia, Spain .....................81.3 %
  • Andalucia East, Spain ............72.0 %
  • Castilla La Mancha, Spain..... 72.0 %
  • Galicia, Spain.........................58.0 %
  • Andalucia West, Spain...........55.0 %

 Complete table with all countries :

Map of frequencies : 

domingo, 17 de julio de 2011

Spaniards genetically similar to Western and Northern Europeans

Study from Gayán et al. 2010 , some extracts :
In this study we have sampled over 800 unrelated individuals from the population of Spain, and have genotyped them with a genome-wide coverage. We have carried out linkage disequilibrium, haplotype, population structure and copy-number variation (CNV) analyses, and have compared these estimates of the Spanish population with existing data from similar efforts. Conclusions: In general, the Spanish population is similar to the Western and Northern Europeans but has a more diverse haplotypic structure. These results suggest that the general Spanish population, as characterized in the present study by sampling from eight different cities widely-spaced across Spain, is generally similar to other European populations, although more genetically diverse than Western and Northern Europeans. Moreover, the Spanish population is remarkably homogeneous within itself in terms of global genetic structure. In view of these results, the population of Spain is sufficiently genetically similar to the CEU sample (White-Americans from Utah) so that the CEU HapMap dataset could be used to infer genotypes for the Spanish population.

North-African mtDNA in Spain...and Europe

The minor presence of the typical north-african mtDNA haplgroup U6  in Spain, even if at low levels, was tought to be higher than anywherelse in Europe. Interestingly we will see that this is not the case. The truth is that U6 is found everywhere in Europe, but it has been found at higher frequencies in France. Obviously these studies make sure the testees are natives, having the 4 grandparents from the same area, and their surnames native. We see now the studies :

In this study of Dubut et al. 2004 there is a total of 4.5% of U6 in Finistère (Brittany, France) and 1.4% in Périgord-Limousin.

In this very recent study of García et al. 2011 we find these frequencies for France :

  • U6a1/a2/a3 Perigord-Limousin (Limousin) 1.4 %
                       Finistère (Brittany) 0.7 %
  • U6a  France Miscellanea 0.6 %
Spain : 

Andalusians n=3/158    1.9%   Plaza 2003.

Asturias   n=1/89     1.1%    Garcia 2011.

Aragón     n=0/119    0.0%    Garcia 2011.

Catalonia-Aragón  n=2/164  1.2%  Garcia 2011.
Catalonia n=3/80    3.9%      Garcia 2011.
Catalonia n=78     0.0 %    Plaza 2003.

Central Spain   n=1/50  2.0%   Plaza 2003.

Basques    n=45  ??   0.6%    Maca-Meyer 2003.
Basques    n=0/377    0.0%    Garcia 2011.
Basques    n=1/85     1.2%    Garcia 2011.
Basques    n=173      0.0%    Plaza 2003.

Galicia      ??       2.3%    Maca-Meyer 2003.
Galicia    n=3/185    1.5%    Garcia 2011.
Galicia    n=2/103      1.9%    Plaza 2003.

Cantabria  n=1/105    1.0%    García 2011.
Potes      n=0/72     0.0%    Maca-Meyer 2003.

Lebaniegos n=0/72   0.0%      Maca-Meyer 2003.
Pasiegos   n=0/82   0.0%      Maca-Meyer 2003.

Valencia   n=0/30     0.0 %     Plaza 2003.

% M1 and U6a1a = 2/214 = 0.93%   Álvarez 2010

TOtal SPain = 18/2.022 = 0.89%

sábado, 16 de julio de 2011

Genetic continuity since pre-Roman times

In this study of Sampietro et al. 2005 have retrieved mitochondrial DNA (mtDNA) from a few of the scarce skeletal remains that have been preserved. 
Phylogeographic analyses show that the haplogroup composition of the ancient Iberians was very similar to that found in modern Iberian Peninsula populations, suggesting a long-term genetic continuity since pre-Roman times.

Here is the whole summary :

The Iberians developed a surprisingly sophisticated culture in the Mediterranean coast of the Iberian Peninsula from the 6th century BC until their conquest by the Romans in the 2nd century BC. They spoke and wrote a non-Indo-European language that still cannot be understood; their origins and relationships with other non-Indo-European peoples, like the Etruscans, are unclear, since their funerary practices were based on the cremation of bodies, and therefore anthropology has been unable to approach the study of this people. We have retrieved mitochondrial DNA (mtDNA) from a few of the scarce skeletal remains that have been preserved, some of them belonging to ritualistically executed individuals. The most stringent authentication criteria proposed for ancient DNA, such as independent replication, amino-acid analysis, quantitation of template molecules, multiple extractions and cloning of PCR products, have been followed to obtain reliable sequences from the mtDNA hypervariable region 1 (HVR1), as well as some haplogroup diagnostic SNPs. Phylogeographic analyses show that the haplogroup composition of the ancient Iberians was very similar to that found in modern Iberian Peninsula populations, suggesting a long-term genetic continuity since pre-Roman times. Nonetheless, there is less genetic diversity in the ancient Iberians than is found among modern populations, a fact that could reflect the small population size at the origin of the population sampled, and the heterogenic tribal structure of the Iberian society. Moreover, the Iberians were not especially closely related to the Etruscans, which points to considerable genetic heterogeneity in Pre-RomanWestern Europe.

Bioanthropology of the Ebro Valley

This is a study from José Luis Nieto Amada called "La biolantropologia del Valle del Ebro" (bioanthropology of the Valley of Ebro) from 1983. The studied populations are the valley of Ebro, that is, from the provinces of Navarra, Rioja, Huesca, Zaragoza, Teruel and part of Lleida. That is, in the Northeast area of Spain.

Here are some quotes from the study :

"In the lands of Ebro, there is a predominance of dark chestnut hair color".

"According to Sánchez Fernández, Zaragoza would be the province with the highest percentage of blondism, with more than 30%. The percentages of Huesca and La Rioja would also be among the highest "

"Our statistics are far from these frequencies, and we place in the Ribera Zaragozona and Navarra (20.5%) the highest concentration of blondism. " 

"In our study, the highest frequencies of blue eyes appear in the communities with also the highes percentage of azure iris. The distribution is very homogeneus between navarrese and aragonese, with a marked difference in the Ribera (21%) and the middle basin of Jiloca. Wheras in Rioja, the percentage is much lower."

Y-chrosome haplogroup R1b in Spain

Paternal Y-chromosome haplogroup R1b subclades frequency in Europe from the study of Myres et al. 2010. As we can see, the highest frequencies in Iberia are M269, M412 (all), L11 (all), S116 (all), and S116*.