AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 131:539–551 (2006)
Human Mitochondrial DNA Diversity in an Archaeological Site in al-Andalus: Genetic Impact of Migrations from North Africa in Medieval Spain
Marı´a Jose´ Casas,1* Erika Hagelberg,1 Rosa Fregel,2 Jose´ M. Larruga,2 and Ana M. Gonza´ lez2
1Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, B l i n d e r n , 0 3 1 6 O s l o , N o r w a y Departamento de Gene´tica, Universidad de La Laguna, 38271 La Laguna, Tenerife, Spain 2
aDNA; haplotypes; Andalusia; Iberia
Mitochondrial DNA sequences and restric-
tion fragment polymorphisms were retrieved from three Is- lamic 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 sam- ples from the present population of the same area, the me- dieval 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 sam- ple from the same area. The increased gene flow in modern times could be the main cause of this difference. Am J Phys Anthropol 131:539–551, 2006. V C 2 0 0 6 W i l e y - L i s s , I n c .
The origin of the genetic diversity of human popula- tions in Europe is still very controversial, despite the multidisciplinary approach of the research being used to address this question. At this point, ancient DNA studies can contribute by providing at least a piece of the genetic landscape at a precise time in the past, and so they can help shed light on the origin of the genetic com- position of present populations.
Most of the research regarding the origin and evolu- tion of the Iberian population is based on modern DNA analysis of autosomic markers, Y-chromosome, and mito- chondrial DNA (Coˆrte-Real et al., 1996; Comas et al., 2000; Flores et al., 2000; Bosch et al., 2001; Gonza´lez et al., 2003). For mitochondrial DNA, it shows a high similarity with other European populations (Richards et al., 1996), although perhaps the most important dif- ference is due to the presence, though at low frequen- cies, of haplogroups U6 and M1 (Macaulay et al., 1999; Gonza´lez et al., 2003), which were probably introduced from North Africa, where U6 and M1 are predominant (Rando et al., 1998). This distribution indicates moderate levels of gene flow from North Africa to the Iberian Pen- insula (Coˆrte-Real et al., 1996; Rando et al., 1998) that would have occurred during the Muslim occupation of the Peninsula (Bosch et al., 2001; Larruga et al., 2001), but also in prehistoric times (Gonza´lez et al., 2003) in proportions that remain unknown.
The frequency of African lineages in Iberia is highest in Andalusia (7.7%), and the frequency of the European haplogroup H is also more similar to North Africa than to the North of the Iberian Peninsula.
Iberia was conquered by Muslims of northwest (NW) African and Arab origin at the beginning of the eighth century A.D., and their political domination over part of the Peninsula extended until the 15th century. During these eight centuries the limits of the area under their political control changed considerably, with the South, and in particular Andalusia, being the region where the
occupation lasted the longest. The historical records describe how Arabs and Berbers settled the conquered territory. Arabs were a minority who arrived mainly dur- ing the conquest, while Berbers immigrated throughout during the whole period of Muslim domination in signifi- cantly higher numbers. Berbers, together with the mainly Christian, but also Jewish, local population, adopted the Islamic religion and culture, although at dif- ferent rates and degrees depending on the areas. It has been proposed that by the 10th century, Islam would have been the religion of 50% of the population (Car- rasco et al., 2002). The last important military efforts for the Islamic control of the area occurred during the 11th and the 13th centuries when al-Andalus (the Arabic term for the territory under Muslim domination) became a part of the Almoravide and Almohade empires. Both political movements originated in Berber regions of North Africa and were probably accompanied by new waves of Berber immigrants.
The archaeological excavations held between 1995 and 2000 in Priego de Cordoba (Andalusia, Spain) (Carmona and Luna, 1996; Carmona et al., 1998; Carmona, 1999) enabled us to obtain human remains from three different
Grant sponsor: The Spanish Ministerio de Educacio´n; Grant num- ber: 2002 EX 9/30/02; Grant sponsor: Ministerio de Ciencia y Tecno- logı´a; Grant number: BMC2001-3511; Grant sponsor: Gobierno de Canarias; Grant number: COF2002-015.
*Correspondence to: Marı´a Jose´ Casas, c/ Ramo´n Pe´rez de Ayala 112, 1A, 28015 Madrid, Spain. E-mail: firstname.lastname@example.org
Received 11 October 2005; accepted 21 March 2006.
DOI 10.1002/ajpa.20463 Published online 9 May 2006 in Wiley InterScience (www.interscience.wiley.com).
V C 2 0 0 6 W I L E Y - L I S S , I N C .