Human maternal heritage in Andalusia (Spain): its composition reveals high internal complexity and distinctive influences of mtDNA haplogroups U6 and L in the western and eastern side of region

Abstract

BackgroundThe archeology and history of the ancient Mediterranean have shown that this sea has been a permeable obstacle to human migration. Multiple cultural exchanges around the Mediterranean have taken place with presumably population admixtures. A gravitational territory of those migrations has been the Iberian Peninsula. Here we present a comprehensive analysis of the maternal gene pool, by means of control region sequencing and PCR-RFLP typing, of autochthonous Andalusians originating from the coastal provinces of Huelva and Granada, located respectively in the west and the east of the region.ResultsThe mtDNA haplogroup composition of these two southern Spanish populations has revealed a wide spectrum of haplogroups from different geographical origins. The registered frequencies of Eurasian markers, together with the high incidence and diversification of African maternal lineages (15% of the total mitochondrial variability) among Huelva Andalusians when compared to its eastwards relatives of Granada and other Iberian populations, constitute relevant findings unknown up-to-date on the characteristics of mtDNA within Andalusia that testifies a female population substructure. Therefore, Andalusia must not be considered a single, unique population.ConclusionsThe maternal legacy among Andalusians reflects distinctive local histories, pointing out the role of the westernmost territory of Peninsular Spain as a noticeable recipient of multiple and diverse human migrations. The obtained results underline the necessity of further research on genetic relationships in both sides of the western Mediterranean, using carefully collected samples from autochthonous individuals. Many studies have focused on recent North African gene flow towards Iberia, yet scientific attention should be now directed to thoroughly study the introduction of European genes in northwest Africa across the sea, in order to determine its magnitude, timescale and methods, and to compare them to those terrestrial movements from eastern Africa and southwestern Asia.

Genetic affinities among the historical provinces of Romania and Central Europe as revealed by an mtDNA analysis

“…As for haplogroup L, we found two samples with L3, one in Wallachia and the other in Dobrudja (0.28%), consistent with the low frequencies found in European populations [39], except in the Iberian Peninsula, where Western Andalusians have high frequencies of African lineages [40]. The occurrence of the African haplogroup L might be the result of colonists from African provinces during the Roman period or the recent slave trade that generated movements of African people from the Ottoman Empire to East Europe at the beginning of the 17 th century.…”

New insights into the distribution ofAPOEpolymorphism in the Iberian Peninsula. The case of Andalusia (Spain)

“…Previous studies carried out by our team based on Y-chromosome markers support the presence of a Berber and North African signature in contemporary Andalusian populations (Ambrosio et al, 2010a, b). In this line, analysing mtDNA haplogroups on the same stock of Andalusian samples, we have also detected a fair presence of typically Northern and Sub-saharan African lineages in the region (Hernández et al, 2014).…”

Immunoglobulin genes in Andalusia (Spain). Genetic diversity in the Mediterranean space

“…Maghreb peopling must then have taken place -at least, partially -from the Iberian Peninsula [71,72], which constituted an important refuge during Last Glacial Maximum (LGM, 11-18 kya). Prolonged and ancient contacts are further explained in Athanasiadis and Moral [31]. The Islamic rule in Iberia favoured those contacts.…”

“…Recent results obtained by our group on the composition and mtDNA variation in Andalusia [31] reveal high internal complexity and a distinctive influence of U6 and L haplogroups in both eastern and western side of region. Investigating Y-chromosome variability in the same sample sets, we also observe interpopulation genetic differentiation, though in a lesser extent ( [32,33], Calderó n et al manuscript in preparation).…”

“…The similar GM*1,17 23 0 5* frequencies ($ 0.04) in Andalusia and Galicia (regions for which Muslim domination was very uneven) can be explained by the connection between southwestern and northwestern Iberia through the Roman Via de la Plata (''silver way''). This road acquired remarkable military and trading importance, since it connected important cities and mining deposits, and facilitated population movements during long periods (this scenario is further explored in [31]). Other possibility are long-range maritime travels along the Iberian Atlantic façade, mainly motivated by tin search at mining sites in northwest peninsular Iberia, that dates from the Bronze Age (the Early Bronze age started in Iberia towards 2250 BC, with a presence recorded in southern Iberia since 3500 BC).…”