viernes, 25 de noviembre de 2011

North-African marker in Andalusia

We find the following percentages for the typcial north-african (Berber) paternal marker, the Y-DNA haplogroup E-M81, obtained from different sources :

Southern Spaniards  n=1/62    1.6%    Scozzari 2001.
Huelva, Andalusia   n=5/167   2.99%  Ambrosio 2010.
Huelva, Andalusia   n=1/22      4.5%   Flores et al.2004
Seville, Andalusia  n=7/155     4.5%    Flores et al.2004
Cadiz, Andalusia    n=0/28      0.0%    Flores et al.2004
Cordoba, Andalusia  n=2/27   7.4%    Flores et al.2004
Malaga, Andalusia   n=3/26    11.5%   Flores et al.2004
Andalusia East      n=2/95       2.1%    Adams et al.
Andalusia West      n=10/73   13.7%   Adams et al.
-------------------------
Total South Spain :  31/655 = 4.73%


It is a similar result to percentages found in  French  (3/73 = 4.1% , Scozzari et al. 2001) or in regions of France ( 5.6% in Auvergne (5/89) and Île-de-France 5/91 = 5.5% ). This suggests that the presence of Islamic rule, which was longer in the South of Spain than anywhere else in Iberia, had very limited or no impact in the genetic pool of the population. We can conclude that the moorish population in Andalusia was extremely minoritary, the place were Islamic rule was stronger and longer. We can't also rule out the possibily that the presence of this marker, or part of it, could have entered in much earlier times (Neolithic or earlier), which would make the presence of moors in Al-Andalus even more insignificant. So, in other words, we can safely say the Islamic rule was just that, a military and religious rule, with no impact on the demographics and genetics of the authoctonous populations.


Ambrosio et al. 


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.

lunes, 7 de noviembre de 2011

Sub-Saharan admixture in the Mediterranean basin

González-Pérez et al. (2010) have analyzed populations from the northern and southern shores of the Mediterranean, with Central Europeans and West Africans as external references. In the Discussion section, they admit that the inflated "Alu/STR estimate might be artefactual" and favor the estimate based on the Alu  loci set alone because it's consistent with previous mtDNA, Y-chromosome and 500,000-SNP structure data.
According to the more accurate latter method, Sub-Saharan African admixture is ~13% in North Africa and "imperceptible" or noise (~ 0.01%) in Southern Europe:


miércoles, 2 de noviembre de 2011

Pyrenean Y-DNA


In the pie charts, dark blue refers
to R1b1b2d, dark light to R1b1b2c, white to other R, orange
to I2a2, salmon to other I and pink to lineages that entered
Iberia from the Neolithic onwards. The light gray slice refers to
R plus I lineages.
From the study of  López-Parra et al. 2009 which analyses 5 pyrenean populations (25 males from Vall d'Arán (Lleida province), 34 from Alt Urgell (Lleida province), 37 from Cerdanya (Girona province), 31 from Jacetania (Huesca province) and 42 from Cinco Villas (Navarre province).


As expected, the vast majority by far of these populations belong to haplogroup R1b1b2-M269 (total 131/169 = 77.5%), especially the subhaplogroup R1b1b2*, and the second most common haplogroup among the total Pyrenean samples was haplogroup I which accounted for 12.4% (21/169) of paternal lineages, being I2a2 the most common clade. The rest of haplogroups are quite minoritary. Here are the distributions for each of the pyrenean populations sampled :

Cerdeña (n=37)
R1b: 75.7%  I: 16.2%  G : 2.7%  J: 2.7%  E: 0% 

Alt Urgell (n=34)
R1b: 76.5%  I: 8.8%  J: 8.8%  E: 2.9% 

Vall d'Arán (n=25)
R1b : 84%  I: 12%  E: 4%  J: 0%

Jacetania (N=31) :
R1b : 64.%  I: 16.1%   J: 9.7%  R1: 6.45%    G: 3.2%   E: 0%

Cinco Villas (n=42)
R1b: 85.7%  I:  14.3%

TOTAL (n=169) :  R1b (131/169) : 77.5%  I (21/169) : 12.4%  J (7/169) = 4.14%, G (3/169) = 1.78% E (3/169) = 1.78%,    R1 (2/169) = 1.18%  and  Other 2/169 = 1.18%.

Summary

The male-mediated genetic legacy of the Pyrenean population was assessed through the analysis of 12 Y-STR and 27 Y-SNP loci in a sample of 169 males from 5 main geographical areas in the Spanish Pyrenees: Cinco Villas (Western Pyrenees), Jacetania and Valle de Arán (Central Pyrenees) and Alto Urgel and Cerdaña (Eastern Pyrenees). In the Iberian context, the Pyrenean samples present some specificities, being characterizeded by a high proportion of chromosomes R1b1b2-M269 (including the usually uncommon R1b1b2d-SRY2627 and R1b1b2c-M153 types) or I2a2-M26 and low proportions of other haplogroups. Our results indicate that an old pre-Neolithic substrate is preponderant in populations of the whole Pyrenean fringe. However, AMOVA revealed a high level of substructure within Pyrenean populations, partially explained by drift effects as well as by the signature of an ancient genetic differentiation between Western and Eastern Pyrenees.

Other interesting extracts from the study : 

I2a2 is virtually absent east of the Italian Apennines and shows the highest incidences in north-eastern Iberia/southern France, with the exception of the isolated and dramatic peak of frequency (40.9%) in Sardinia (Rootsi et al. 2004).
This was well illustrated in the phylogram of I2a2 in Figure 1 from Rootsi et al. (2004) based upon the population data available at the moment, within which Basques (Spanish and French mixed) and Bearnais (in the French Atlantic Pyrenees) showed the highest continental frequencies (6% and 7.7% respectively). New data from Spanish Basques (Alonso et al. 2005) did not reproduce such elevated values; in Biscay I2a2 was not detected and its frequency was 1.3% in Gipuzkoa and 4.5% in Alava plus Navarra. From the new data presented here it seems that the Pyrenees might indeed have been the region where I2a2 arose and from which it initiated the spreading process after the LGM.

One of the signs comes from the concentration of high frequencies of I2a2 among populations from the entire Pyrenean range. Our data strongly reinforce previous evidence that I2a2 arose during Mesolithic times in a region close to or within the Pyrenees. The dispersal of I2a2 from its place of origin throughout the Pyrenees and beyond, implied not only gene exchange but also considerable movement of people. Very likely, the demographic event associated with the expansion of I2a2 was the Ice-age repopulation of
Europe from the Franco-Cantabrian refuge. A number of studies on human mtDNA diversity have already indicated that the Franco-Cantabrian glacial refuge was a major source for the European gene pool (Achilli et al. 2004), and our data on I2a2 seemingly lend support to the role of the region as a Mesolithic diffusion center of male lineages.

lunes, 31 de octubre de 2011

Celtiberia population estimate


From the book  ENTRE Celtas e Íberos. Las poblaciones protohistóricas de las Galias e Hispania/ editado por Luis Berrocal-Rangel y Philippe Gardes. — Madrid : Real Academia de la Historia : Casa de Velázquez, 2001. — 248 p. : il. ; 30 cm. —(Bibliotheca Archaeologica Hispana ; 8).

Note, the Celtiberia here refers only to the proper Celtiberian tribes, and not all the Celts of Iberia.

Abstract

The demographic analysis of the Celtiberian is a hard question. To solve it we have analysed the ethnoarchaeological data and we have contrasted it with archaeological data, as the surface of the known Celtiberian civitates and oppida. We have contrasted the results with the few informations transmitted by classical historians and geographers, as the numbers of warriors in Celtiberian armies and the extension of the populi and civitates of Celtiberia after Plinius and Ptolomeus. As conclusion of the analysis, we can consider that Celtiberia, extended about 45.000 km2 had a theoretical demographic density of about 5/6 h./km2 in mountain areas, but could reach 8/10 h./km2 in the best areas, as river valleys and peripheral plains. These results allow us a calculation of the total Celtiberian population between 250.000 h. and about 350.000/450.000 h., a bigger and more logical number. The first demographic anlysis of the Celtiberia offers a interesanting information and very useful for further studies on Archaeology and Ancient History and Geography, and also to better understand the territorial and urban planning, the demography and the sociology of the Celtiberians.

ADMIXTURE up to K=20 (Rasmussen et al. 2011)

The recently published paper by Rasmussen et al. is focused on the Aboriginal Australians, and inlcudes a massive ADMIXTURE analysis up to 20 ancestral components (K=20). The Spaniard sample (taken from Behar et al.) in this run is similar-looking to other Western-European populations, showing the dark-blue component (peaks in Lithuanians) at similar levels as the French, and the whiteish-blue component (peaks in Sardinians).

The original size can be found in the supplementary PDF here (page 159) :

martes, 16 de agosto de 2011

Sub-Saharan haplogroup mtDNA L in Spain and Europe

In the study of Rhouda et al. (2006) in a sample of 686 spaniards, not a single individual with haplogroup mtDNA L was found. In the rest of Western Europe, the recent study of García et al. 2011 finds L up to Northern Germany and Denmark . We observe the following percentages  :

Hérault (Languedoc) 2.4 %
Rhône (Lyonnais) 4.4 %
Vendée and Vienne (Poitou) 0.8 %
Calvados and Seine-Maritime (Normandy) 1.8 %
Somme (Picardie) 1.3 %
France Miscellanea 0.6 %
Scotland 0.1 %
England 0.7 %
Great Britain 0.9 %
North-Germany and Denmark 0.7 %



miércoles, 3 de agosto de 2011

Skin reflectance of selected world populations

From the study of Nina Jablonski and George Chaplin (Academy of Sciences of California).
We can see that Spaniards, from León (NW Spain) and Basques (N Spain), are as light or even lighter than other Western Europeans. Higher values indicate lighter skintone.

Country and population or area

Observed reflectance at 685 nm

EUROPE
Netherlands
67•37
Germany (Mainz)
66•90
United Kingdom (Northern)
66•10
Spain (Basques) 65•70
United Kingdom (Wales) 65•00
Ireland (Rossmore)
64•75
Spain (Leon)
64•66
Belgium
63•14
United Kingdom (London) 62•30
WEST ASIA
Iraq/Syria (Kurds) 61•12
Turkey
59•15
Israel
58•20
Lebanon
58•20
Jordan
53•00
Saudi Arabia 52•50
NORTH AFRICA
Algeria (Aures) 58•05
Tunisia
56•30
Morrocco
54•85
Libya (Tripoli)
54•40
Libya (Fezzan) 44•00
SOUTH ASIA
India (Northern) 53•26
Pakistan 52•30
India (Southern) 46•70
EAST ASIA
China (Southern) 59•17
Vietnam 55•90
Japan (Northern) 54•90
Philippines (Manila) 54•10
Cambodia 54•00
Japan (Southwest) 53•55
Nepal (Eastern) 50•42
AUSTRO-MELANESIA
Papua New Guinea 35•30
Australia (Darwin) 19•30
AMERICAS
Greenland (Southern) 55•70
Peru (Nunoa) 47•70
Peru (Maranon) 43•05
SUB-SAHARAN AFRICA
South Africa (Hottentot) 46•80
Botswana (San) 42•40
Zaire 33•20
Kenya 32•40
Ethiopia 31•70
Tanzania (Sandewe) 28•90
Namibia 25•55
Cameroon (Fali) 21•50
Mozambique (Chopi) 19•45


Source : "The Evolution of Human Skin Coloration". J Hum Evol, 2000; pp. 74-75