The most recent scientific studies have also confirmed that Portugal has substantial sub-Saharan mtdna.
In Iberia the mean frequency reaches 3.83% and the frequency is higher in Portugal (5.83%) than in Spain (1.61%) and without parallel in the rest of Europe. Furthermore, in western Iberia, increasing frequencies are observed for Galicia (3.26%) and northern Portugal (3.21%), through the center (5.02%) and to
the south of Portugal (11.38%).[21]
Relatively high frequencies of 7.40% and 8.30% was also reported respectively in South Iberia (Spain and Portugal) and in the present population of Priego de Cordoba by
Casas et al. 2006[22]. Significant frequencies were also found in the Autonomous regions of Portugal, with
L haplogroups constituting about 13% of the lineages in Madeira and 3.4 % in the Azores. In the spanish archipelago of
Canary Islands, frequencies have been reported at 6.6%.[23]
http://goliath.ecnext.com/coms2/gi_0199-4707358/African-female-heritage-in-Iberia.html
African female heritage in Iberia: a reassessment of mtDNA lineage distribution in present times.
Publication: Human Biology
Publication Date: 01-APR-05
[...]
Sub-Saharan African Influence. The mean frequency for the sequences belonging to superhaplogroup L, typical for sub-Saharan populations, reaches 3.83% ([+ or -]0.59%) in Iberia, representing 40 sequences in the total sample of 1,045 individuals.
The frequency is clearly higher (Figure 1) in Portugal (32 sequences in 549 individuals; 5.83%) than in Spain (8 out of 496; 1.61%) and without parallel in the rest of Europe. Furthermore, in western Iberia, increasing frequencies are observed for Galicia and northern Portugal (3.26% and 3.21%, respectively--a value similar to the one found in the rest of Spain) through the center (5.02%) and to the south (11.38%). The overall geographic Iberian heterogeneity is highly significant (p = 0.0003 in the chi-square for the 2 X 9 contingency table), as is the heterogeneity for the four western populations (p = 0.0110).
This pattern is also consistent with historical reports referring to a predominant introduction of slaves in southern Portugal (Lahon 1999).
http://www.ncbi.nlm.nih.gov/pubmed/16685727
Am J Phys Anthropol. 2006 Dec;131(4):539-51.
Human mitochondrial DNA diversity in an archaeological site in al-Andalus: genetic impact of migrations from North Africa in medieval Spain.
Casas MJ, Hagelberg E, Fregel R, Larruga JM, González AM.
Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, Blindern, 0316 Oslo, Norway.
[email protected]
Mitochondrial DNA sequences and restriction fragment polymorphisms were retrieved from three Islamic 12th-13th century samples of 71 bones and teeth (with >85% efficiency) from Madinat Baguh (today called Priego de Cordoba, Spain). Compared with 108 saliva samples from the present population of the same area, the medieval samples show
a higher proportion of sub-Saharan African lineages that can only partially be attributed to the historic Muslim occupation. In fact, the unique sharing of transition 16175, in L1b lineages, with Europeans, instead of Africans, suggests
a more ancient arrival to Europe from Africa. The present day Priego sample is more similar to the current south Iberian population than to the medieval sample from the same area. The increased gene flow in modern times could be the main cause of this difference. 2006 Wiley-Liss, Inc.