New study about Zamora
There is a very interesting new study by Luis Alvarez 2010 about "Mitochondrial DNA patterns in the Iberian Northern plateau: Population dynamics and substructure of the Zamora province".
The authors found 10 L mtDna sub-saharan lineages out of 214 which gives 4.70% in the province of Zamora.
Quote from the authors :
"One of the distinctions between the mtDNA composition of the Iberian Peninsula with respect to other European populations is the presence of North African and sub-Saharan lineages [for revision, see Arroyo-Pardo et al. (2007)]. In Zamora, both North African and sub- Saharan mtDNA lineages were found"
L lineages mtDNA frequencies
So here are a new summary of the L lineages mtDNA frequencies found in Spain including this new study by Alvarez. This includes ALL the data ever published so far about Spain (1680 distinct individuals from continental Spain and 531 from Spanish Islands)
1) Continental Spain
Spain, northwestern : 8/216 =3.70%, Achilli 2007
Spain, central : 1/148 =0.68%, Achilli 2007
Spain, Andalusia: 2/114 =1.75%, Achilli 2007
Spain, northeastern : 3/179 =1.68%, Achilli 2007
Spain, Basque Country: 1/156 =0.64%, Achilli 2007
Spain, all regions : 9/312 =2.90%, Alvarez 2007
Spain, Pyreneans : 0/233 =0.00%, Lopez-Parra 2009
Spain, Cordoba : 9/108 =8.30%, Casas 2006 (highest frequency found in Spain)
Spain, Zamora: 10/214 =4.70%, Luis Alvarez 2010
Total continental Spain : 43/1680 = 2.55 %
2) Islands
Spain, Balearic : 5/231 =2.20%, Picornell 2005
Spain, Canaries : 20/300 =6.60%, Brehm 2003
3) All Spain
Of course it does not make sense at all to average regions with totally different histories like Basque Country (lowest frequency in Spain) or the province of Cordoba (highest frequency in Spain at 8.30%, almost similar to South Portugal) , and because northern populations are overrepresented in the studies, but if we want to do it we get :
All Spain (including Balearic and Canaries) : 68/2211= 3.07%
==Sources==
a) Achilli 2007 (Mitochondrial DNA Variation of Modern Tuscans Supports the Near Eastern Origin of Etruscans) aggregated data from the following sources :
Salas 1998, mtDNA analysis of the Galician population: a genetic edge of European variation.
Richards 2000, Tracing European founder lineages in the Near Eastern mtDNA pool
Crespillo 2000, Mitochondrial DNA sequences for 118 individuals from northeastern Spain
Larruga 2001, Mitochondrial DNA characterisation of European isolates: the Maragatos from Spain
Plaza 2003, Joining the pillars of Hercules: mtDNA sequences show multidirectional gene flow in the western Mediterranean.
González 2003, Mitochondrial DNA affinities at the Atlantic fringe of Europe
b) Others studies not included by Achilli 2007
Brehm 2003, Mitochondrial portraits of the Madeira and Açores archipelagos witness different genetic pools of its settlers
Picornell 2005, Mitochondrial DNA HVRI Variation in Balearic Populations
Casas 2006, Human Mitochondrial DNA Diversity in an Archaeological Site in al-Andalus: Genetic Impact of Migrations from North Africa in Medieval Spain
Alvarez 2007, Characterization of human control region sequences for Spanish individuals in a forensic mtDNA data set
Lopez-Parra 2009, Preliminary results of mitochondrial DNA sequence variation in Spanish Pyrenean populations
Luis Alvarez 2010, Mitochondrial DNA Patterns in the Iberian Northern Plateau: Population Dynamics and Substructure of the Zamora Province
Pereira 2005 (African Female Heritage in Iberia) analysed 496 samples from the studies above and did not include any new Spanish samples.
HLA Data
Hla data are also a good indicator of sub-saharan ancestry as they are transmitted by all lines
In Spain, the average figure for this African haplotype is 2.4%, whereas in other non-Mediterranean European populations that value is nearly eight times lower (0.3%)
1) Studies about HLA data found similar frequencies of HLA GM*1,17 23' 5* haplotype which is considered a genetic marker of sub-Saharan Africa. (HLA data are autosomal markers and can be inherited from any ancestors instead of only directly through the paternal or maternal line).
The 2 regions with highest frequencies are also Galicia and Andalusia as with mtDNA
Sub-saharan HLA haplotype GM*1,17 23' 5* in Spain (Reported by Calderon 2005) :
Spain, Galicia (357), 4.50%, Calderon et al. (2007)
Spain, Andalusia Huelva (252), 3.80%, Calderon et al. (2006)
Spain, Pyrenean Pallars Sobira (178), 3.70%, Giraldo et al. (2001)
Spain, Pas Mountains (98), 2.50%, Esteban et al. (1998)
Spain, Vizcaya Basques (86), 2.30%, Calderon et al. (1998)
Spain, Guipuzcoa Basques (97), 2.10%, Calderon et al. (1998)
Spain, Valencia (186), 1.90%, Schanfield et al. (1981)
Spain, Pyrenean Aran valley (210), 1.50%, Giraldo et al. (1998)
Spain, Navarre Basques (118), 1.30%, Calderon et al. (2000)
Spain, Alava Basques (122), 1.20%, Calderon et al. (1998)
According to Calderon 2005 about Galicia :
"The GM*1,17 23' 5* haplotype is considered a genetic marker of sub-Saharan Africa, where it shows frequencies of about 80% (Excoffier et al. 1991). A relatively moderate frequency (3.80%) of this haplotype, similar to that found in populations from Galicia (4.5%) and the Pyrenees (3.70%; Giraldo et al. 2001), was observed in Huelva.. this haplotype's frequency ranges between 1% and 3% in most Spanish populations".
According to Calderon 2007 about Andalusia :
"Galician population shows a genetic profile for GM haplotypes that is defined by the high presence of the European Mediterranean GM*3 23 5* haplotype, and the relatively high incidence of the African marker GM*1,17 23´ 5*... The GM*1,17 23´ 5* haplotype shows a peak in Galicia (4.5%), although values of around 4% have also been found in the Aran valley in the Pyrenees... In Spain, the average figure for this African haplotype is 2.4%, whereas in other non-Mediterranean European populations that value is nearly eight times lower (0.3%). Although some researchers have associated African traces in Iberia to Islamic invasions, the presence of GM*1,17 23´ 5* haplotype in the Galician population may in fact be due to more ancient processes"
==HLA data Sources==
Calderon et al. (2006), Genetic position of Andalusians from Huelva in relation to other European and North African populations: a study based on GM and KM allotypes.(genetic markers)
Calderon et al. (2007), GM and KM immunoglobulin allotypes in the Galician population: new insights into the peopling of the Iberian Peninsula
Autosomal DNA
In 2009 a study by Moorjani 2009, "Characterizing the history of sub-Saharan African gene flow into southern Europe" estimated the proportion of African admixture in southern Europe and found an autosomal sub-saharan proportion of 2.4% in whole Spain using hundred of thousands SNPs.
Characterizing the history of sub-Saharan African gene flow into southern Europe. P. Moorjani1, N. Patterson2, J. Hirschhorn1,3, D. Reich1,2 1) Department of Genetics, Harvard Medical School, Boston, MA; 2) Broad Institute, Cambridge, MA; 3) Divisions of Endocrinology and Genetics and Program in Genomics, Children's Hospital, Boston, MA.
Recent analyses of whole-genome SNP data sets have suggested a history of sub-Saharan African ancestral contribution into southern Europe but not in northern Europe, consistent with previous analyses based on the Y-chromosome and mitochondrial DNA. However, there has been no characterization of the proportion of African admixture in southern Europe, or of its date. Here we analyze data from ~450,000 autosomal SNPs in the Population Reference Sample, ~650,000 SNPs from the Human Genome Diversity Panel, and ~1.5 million SNPs from the HapMap Phase 3 Project, and studied patterns of correlation in allele frequencies across populations to confirm the evidence of African ancestry in many southern European populations but not in northern Europeans. Using methods that can infer admixture proportions in the absence of accurate ancestral populations, we estimated that the proportion of sub-Saharan African ancestry in Spain is 2.4 +/- 0.3%, in Tuscany 1.5 +/- 0.3%, and in Greece 1.9 +/- 0.7% (1 standard error). We also studied the decay of admixture linkage disequilibrium with genetic distance, which provided a preliminary estimate of the date of African gene flow into Spain of roughly 60 generations ago, or about 1,700 years ago assuming 28 years per generation. This date is consistent with the historically known movement of individuals of North African ancestry into Spain, although it is possible that this estimate also reflects a wider range of mixture times.
So again it is an average with probably wide ranging variation from 0% to 5% but it is interesting to see that all data (mtDna, HLA and Autosomal) found a similar average sub-saharan ancestry estimation of about 2.5% in Spain most likely due to indirect North African contribution (neolithic or historical) rather than direct sub-saharan through slave. trade.
