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Original Research Article
Y-Chromosome Analysis in a Northwest Iberian Population: Unraveling theImpact of Northern African Lineages
LUIS ALVAREZ,1,2* ESTELA CIRIA,1 SOFIA L. MARQUES,2 CRISTINA SANTOS,1 AND MARIA PILAR ALUJA1
1Unitat Antropologia Biol�ogica, Universitat Aut�onoma de Barcelona, 08193, Bellaterra, Barcelona, Spain2IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, 4200-465 Porto, Portugal
Objectives: To provide new clues about the genetic origin, composition and structure of the population of the Span-ish province of Zamora, with an emphasis on the genetic impact of the period of Islamic rule in the Iberian Peninsula.
Methods: Polymorphisms in the paternally inherited Y-chromosome, Single Nucleotide Polymorphisms and ShortTandem Repeats, were analyzed in 235 unrelated males born in six different regions in the Zamora province.
Results: A relatively homogenous Y-chromosome haplogroup composition was observed in the Zamora province.Haplogroups R1b1-P25 and I-M170, widespread in European populations, accounted for 64.9% of the total sample.Moreover, all of the observed African lineages, accounting for 10.2% of the total variability, belonged to haplogroupshaving Northwest African origin (E1b1b1b-M81, E1b1b1a-b-M78, and J1-M267).
Conclusions: No differences between regions or sub-structure due to geographical boundaries were detected. Thespecific Northwest African male lineages observed contrast with the mitochondrial DNA data, where the majority ofAfrican lineages were found to be sub-Saharan. This work made it possible to study the impact of recent historicalevents in the male gene pool in the province of Zamora in Spain. Am. J. Hum. Biol. 00:000–000, 2014. VC 2014 Wiley Peri-
odicals, Inc.
Research into the genetic diversity in European popula-tions has mainly been focused on the interpretation of large-scale variation patterns in light of prehistoric demographicevents [for a review, see Soares et al. (2010)]. Besides thisapproach, the analysis of the impact of recent historicalevents on the current genetic landscape of human popula-tions, examined from a microgeographic perspective, hasgained relevance in the last decade [for a review, see Jobling(2012)]. Genetic studies in Iberians have not been obliviousto such perspectives, for example, the analysis of popula-tions located in the northwestern quadrant of the IberianPeninsula, and have revealed interesting traits from ananthropological and forensic point of view (Beleza et al.,2006; Larruga et al., 2001; Mairal et al., 2013; Nogueiroet al., 2010; Pardinas et al., 2012; Teixeira et al., 2011).
A study in this specific area of the Iberian Peninsula(Alvarez et al., 2010) that centered on the analysis of themitochondrial DNA diversity pattern of the Spanish prov-ince of Zamora (Fig. 1), found a high frequency of Africanmaternal lineages. Although the presence of African line-ages in Iberia represent, per se, one of the peculiarities ofIberians compared with other Europeans [for a review,see Arroyo-Pardo et al. (2007)], those values reported forthe Zamora province population are one of the highestreported so far in Iberia (Cerezo et al., 2012). Anotherremarkable finding was the high frequency and diversityof Middle Eastern lineages in this population.
The reconciliation of historical and genetic data toexplain such results points to a 300 year period, spanningfrom the middle of the 8th century to the 11th century,when there was Islamic rule in the area. The unstablepolitical/social situation of the Iberian Peninsula at thattime critically influenced the demography of the area.Population movements, accompanied by the southernexpansion/consolidation of the Astur kingdom, affectedthe heterogeneity of Zamora province territories, mainlybecause of the course of the Duero River, which played an
important role as a defensive corridor (L�opez and San-tonja, 1995). The lands situated in the northern area wereresettled at the end of the 8th century, but the southernareas were only definitely part of the Astur kingdom inthe 11th century. In both locations, the origin of the set-tlers is well known and involved Mozarabs from thesouthern Muslim kingdoms, together with people fromNorthwestern Iberia and Southern France, the latter onlybeing referred to in the southern areas of the Duero River(L�opez and Santonja, 1995).
Populations involved in those resettlement events bythemselves do not explain, alone, the pattern of maternallineages found in the Zamora province. In view of widerassumptions, the presence of Middle Eastern lineages inIberia has been commonly attributed to (i) the neolithiza-tion process; and/or (ii) recent influences of Mediterra-nean populations (Arroyo-Pardo et al., 2007), including
This article was published online on 14 August 2014. An error was sub-sequently identified. This notice is included in the online version to indi-cate that have been corrected 22 August 2014.
Contract grant sponsor: Ministerio Espa~nol de Ciencia e Innovaci�on;Contract grant number: CGL2006-07374; Contract grant sponsor: Gener-alitat de Catalunya; Contract grant number: SGR 2014-1420.; Contractgrant sponsor: Fundac~ao para a Ciencia e a Tecnologia; financed by theEuropean Social Funds (COMPETE-FEDER); Contract grant number:PTDC/ATP-DEM/4545/2012 (to S.L.M.); Contract grant sponsor: FCT fel-lowship, funded by POPH-QREN – Promotion of scientific employment,supported by the European Social Fund and national funds of the Ministryof Education and Science; Contract grant number: SFRH/BPD/65000/2009(to L.A.).
*Correspondence to: Luis Alvarez, IPATIMUP, Institute of MolecularPathology and Immunology of the University of Porto, Rua Dr. RobertoFrias s/n, 4200-465 Porto, Portugal. E-mail: [email protected]
Additional Supporting Information may be found in the online versionof this article
Received 3 October 2013; Revision received 3 June 2014; Accepted 15June 2014
DOI: 10.1002/ajhb.22602Published online 00 Month 2014 in Wiley Online Library
(wileyonlinelibrary.com).
VC 2014 Wiley Periodicals, Inc.
AMERICAN JOURNAL OF HUMAN BIOLOGY 00:00–00 (2014)
Sephardic Jews (Teixeira et al., 2011). In parallel, severalarguments have been used to explain the presence of Afri-can lineages in this region. These include (i) prehistoriclinks (Cerezo et al., 2012; Izagirre et al., 2005); (ii) inter-breeding between Christians and Muslims (females) inIberia during the 7th–15th century (Pereira et al., 2005);(iii) the relocation of moriscos (converted Muslims) at theend of the 16th century (Adams et al., 2008); and/or iv)the African slave trade during the 16th–19th centuries(Comissao Nacional para as Comemoracoes dos Descobri-mentos Portugueses, 1999).
To test these scenarios, we use paternally inherited Y-chromosome polymorphisms (Single NucleotidePolymorphisms-SNPs and Sort Tandem Repeats-STRs) toprovide new clues of the genetic origin, composition, andstructure of the Zamora province in the Western Euro-pean context. Moreover, the same strategy adopted byAlvarez et al. (2010) dividing the territory into six regions(see miniature in Fig. 1), is followed to determine thegenetic microdifferentiation.
MATERIAL AND METHODS
Sampling strategy and DNA isolation
Blood samples were taken from 235 unrelated malesborn in the Zamora province after obtaining theirinformed consent. In all cases, a confidentiality question-
naire was completed to obtain, whenever possible, perso-nal data up to the third ancestral generation. The ethicscommittees of the Universitat Aut�onoma de Barcelona(UAB) and the Specialized Attention Board at the Health-care Complex of Zamora, authorized by its Medical Direc-tor, approved this study and the written informedconsent. The regional distribution of each sample wasdefined taking into account the birthplace of the grandfa-ther, resulting in: 36 samples from Aliste (AL), 31 fromBajo Duero (BD), 43 from Benavente (BV), 50 fromCampos-Pan (CP), 47 from Sanabria (SN), and 28 fromSayago (SY).
Total DNA isolation from whole blood was performedusing Jetquick Blood DNA Spin Kit (Genomed) accordingto the manufacturers�recommendations.
Y-SNP genotyping
Thirty-three previously published SNP of the Male-Specific portion of the Y-chromosome (MSY) were analyzedin order to define major lineages. Twenty-two markers(12f2a, LLy22g, M2, M9, M20, M52, M74, M78, M81, M94,M123, M170, M173, M201, M207, M213, M215, M223,M253, 12f2a, SYR4064, and YAP) were typed as previouslydescribed by Alvarez et al. (2009). The remaining elevenmarkers (M92, M102, M166, M172, M267, P15, P16, M153,P25, SRY10831.2, and SRY2627) were typed in a multiplex
Fig. 1. Provincial administrative level in Spain highlighting the geographical location of the Zamora Province (white color); miniature show-ing regional subdivision of the Zamora Province, codes as follows: Aliste (AL), Bajo Duero (BD), Benavente (BV), Campos-Pan (CP), Sanabria(SN), and Sayago (SY).
2 L. ALVAREZ ET AL.
American Journal of Human Biology
assay by MassARRAYTM (Sequenom) technology at theSpanish National Genotyping Centre (CeGen).
The classification of samples into haplogroups wasmade using the phylogeny proposed by Karafet et al.(2008).
Y-STR genotyping
Sixteen Y-STR markers (DYS456, DYS389I, DYS390,DYS389II, DYS458, DYS19, DYS385, DYS393, DYS391,DYS439, DYS635, DYS392, Y GATA H4, DYS437,DYS438, and DYS448) corresponding to 17 loci, asDYS385 includes two locus, were coamplified with theAmpFlSTRVRY-filerTM kit (AB Applied Biosystems, FosterCity, CA) using the manufacturers’ recommendations.The STR profiles were obtained on an ABI 3130XLGenetic Analyzer using GeneMapperVR Software (AppliedBiosystems) in the Servei de Gen�omica, UniversitatAut�onoma de Barcelona. Genotyping of samples was per-formed by comparisons with sequenced ladders includedin the kit and GeneScanTM 500 LIZTM Size Standard(Applied Biosystems).
The locus nomenclature and allele designation wereperformed according to the ISFG guidelines (Gusmaoet al., 2006; Mulero et al., 2006).
Comparative dataset
The comparative analysis was performed using avail-able data of 1212 North Africans [238 from Libya (Ottoniet al., 2011); 102 from Algeria (Robino et al., 2008); 225from Tunisia (Fadhlaoui-Zid et al., 2011; Frigi et al.,2006); and 647 from Morocco (Aboukhalid et al., 2010;Alvarez et al., 2009; Gaibar et al., 2011; Laouina et al.,2011; Palet et al., 2010)], summarized in Supporting Infor-mation Table 1.
Data analysis
The haplogroup and haplotype frequencies were esti-mated by direct counting, and the Bayesian 0.95 credibleregions (95% CR) for the haplogroup distribution were cal-culated, using a Bayesian approach for binomial sam-pling, by means of SAMPLING software (Macaulay,personal communication).
The complete haplogroup composition was used to esti-mate (i) Nei’s gene diversity (Nei, 1987); (ii) possible dif-ferences at a regional level using the exact test ofpopulation differentiation (Raymond and Rousset, 1995);and (iii) the effect of geographical boundaries on regionalpopulations (eastern vs. western; north vs. south; andregions divided by the main rivers) using AMOVA analy-sis (Excoffier et al., 1992), with ARLEQUIN 3.5.1.2 soft-ware (Excoffier and Lischer, 2010). Complementarily, theAMOVA analysis, using Slatkin’s linearized FST pairwisegenetic distance (Slatkin, 1995), was further applied todetect possible geographical substructure based onregional Y-STRs haplotype information
Haplogroups E1b1b1b-M81, E1b1b1a-b-M78 (showingallele 10 in DYS439 locus) and a subset of J1-M267, thataccount for the majority of the variation present in North-western African populations, have been consideredmarkers of the contribution of the Islamic rule period tothe Southern European populations (Cruciani et al., 2004;Francalacci and Sanna, 2008; Semino et al., 2004). Fol-lowing the criteria adopted by Capelli et al. (2009), theposterior distribution of the Time to the Most RecentT
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Y-CHROMOSOME VARIATION IN NORTHWEST IBERIA 3
American Journal of Human Biology
Common Ancestor (TMRCA) for any pair of haplotypesdiffering at k loci, was calculated for these specific hap-logroups, using the Infinite Alleles Model (IAM) approachimplemented by Walsh (2001). This model is considered areasonable approximation of when individuals match atmost markers, and therefore, few mutations are expectedto occur as in the short temporal framework consideredhere (1.3ky) (Capelli et al., 2009; Walsh, 2001). Consider-ing 16 Y-STR markers (17 loci) with an overall mutationrate of 2.458 3 1023 estimated over �192,000 meiosis,data available in the YHRD database (Willuweit et al.,2007), in a temporal framework of 1300 years (the year711 marks the beginning of the Islamic rule period in Ibe-ria), encompassing 42 generations [31-year generationlength according to Helgason et al. (2003)].
In this scenario, 0, 1, 2 or 3 mutational differences arethe most likely consequence (Supporting InformationFig. 1 and Supporting Information Table 2). Therefore,the Zamora province Y-chromosomes belonging to the con-sidered haplogroups (E1b1b1b-M81, E1b1b1a-b-M78, andJ1-M267) identical, with one, two or three mutational dif-ferences from the Northwest African STR haplotypes,were considered compatible with an Islamic rule periodancestry.
Several Northwest African populations were evaluatedas the possible source of the Islamic rule period ancestryof the Zamora province. A dataset combining geographicaland cultural information was compiled for this purpose.The probability of origin at each population and its stand-ard deviation was calculated as defined by Mendizabalet al. (2008). Match haplotypes considered in the analysiswere defined in a two-step process: (1) haplotypes of thedataset with 0, 1, 2, or 3 mutational differences to theZamora province ones; and (2) haplotypes inside each
dataset subpopulation with 0, 1, 2, or 3 mutational differ-ences to the ones selected in the first-step. Therefore, theprofiles selected in the first step were considered as thecentral/ancestral population from which, in the temporalframework analyzed, both the Zamora and the remainingdataset subpopulation have equal probability to be theirdescendants.
The dataset included 1212 North African samples (Sup-porting Information Table 1) for which the same 17 STRsloci analyzed in this study were genotyped. Within theselected North African populations, the haplogroup classi-fication, if not available, was inferred from the Y-STR hap-lotypes using the web-accessible program Whit Atheys’Haplogroup Predictor (www.hprg.com/hapest5/), based ona Bayesian allele frequency approach. Complementarilythe DYS458.2 allele was used to determine the J1 chromo-somes (Myres et al., 2007). With the aim of confirming theefficiency of the method, a prediction test was performedusing all the samples for which both STRs and SNPs wereavailable. As a result, a total of 93.2% of correct assign-ments were obtained for the general data, and 94.8% fordata regarding the E1b1b haplogroup (Supporting Infor-mation Table 1).
RESULTS AND DISCUSSION
The analysis of the 17 Y-STR loci discriminated 219haplotypes (Supporting Information Table 3) in the 235analyzed Y-chromosomes. Moreover, according to the 33genotyped SNPs, samples were classified into 19 differenthaplogroups and subhaplogroups, amongst the possible34 (Table 1). The four main branches, E*-M215, I*-M170,J*-12f2a, and R1*-M173, had higher frequencies (�8%),accounting together for up to 91.8% of the detected
TABLE 2. Estimated probabilities for the each country, ethnic/linguistic group and population considered in the matching analysis and the cor-responding standard deviations (SD)
Country Ethnic/Language Population Sample Size E1b1b (%) Probability (SD)
LibyaCosmopolitan 238 64 (26.9) 9.0 (8.3)
Benghazi ” ” 4.8 (6.2)Tunisia
Berbers 160 125 (78.1) 14.7 (10.2)Sejenane 47 24 (51.1) 3.8 (5.5)Takrouna 19 19(100) 9.7 (8.5)Chenini-Douiret 27 27 (100) 1.3 (3.3)Jradou 32 32 (100) 10.2 (8.7)Sened 35 23 (65.7) 5.7 (6.7)
Adalusians 32 14 (43.8) 10.5 (8.8)Zaghouan ” ” 5.8 (6.7)
Arabs 33 22 (66.7) 13.6 (9.9)Tunis ” ” 7.3 (7.5)
AlgeriaArabs 102 52 (51.0) 11.2 (9.1)
Oran ” ” 5.7 (6.7)Marocco
Berbers 190 108 (56.8) 11.6 (9.2)Rabat 69 34 (49.3) 6.2 (7.0)Figuig Oasis 52 17 (32.7) 4.2 (5.8)Khenifra 36 26 (72.2) 5.1 (6.4)Azgour Valley 33 31 (93.9) 6.0 (6.9)
Arabs 223 105 (47.1) 10.3 (8.8)Rabat 130 61 (46.9) 6.5 (7.1)Figuig Oasis 44 8 (18.2) 6.2 (7.0)El Jadida 49 36 (73.5) 1.2 (3.1)
Sahrawi 68 37 (54.4) 10.8 (9.0)Rabat ” ” 6.1 (6.9)
Cosmopolitan 166 91 (54.8) 8.4 (8.0)Casablanca ” ” 4.2 (5.8)
4 L. ALVAREZ ET AL.
American Journal of Human Biology
variability (15 of the 19 detected clusters), with R1*-M173being the most frequent (59.3%) by far. The haplogroupfrequency values obtained for the different regionsshowed a relative homogeneity with overlapping Bayesian0.95 credible regions (Table 1).
Diversity values and substructure analysis
Diversity values based on haplogroup frequencies (H) inthe analyzed chromosomes are listed in Table 1. TheZamora province population (0.684) is in the same rangeas other populations of the same geographic area, forexample, 0.638 and 0.620 in the Spanish regions of Galiciaand Northwest Castile, respectively (Adams et al., 2008),and 0.642 in North Portugal (Beleza et al., 2006). In gen-eral, lower values correspond to those populations locatedin the northeastern quadrant, whereas those located inthe north to southwestern portion had higher values.
The observed pattern in the Iberian Peninsula was alsoobserved at the Zamora regional level (Table 1). Higherdiversity (H) values are present in the western regions(highest in AL: 0.811 6 0.060) and lower values in theeastern ones (lowest in BV: 0.574 6 0.089), the latterbeing in the same range as the populations located in thenortheastern quadrant of Iberia.
The haplogroup distribution of the different regionswas tested to further investigate the underlying substruc-ture of the province. First, the exact test of population dif-ferentiation (Raymond and Rousset, 1995) only showedstatistically significant differences between SY and theeastern regions of BD and BV (P 5 0.029 and P 5 0.024),but no differences were observed when the Bonferroni cor-rection for multiple testing was applied. On the contrary,the AMOVA analysis (Excoffier et al., 1992) at both hap-logroup and haplotypes (Y-STRs) levels showed no signifi-cance when taking the Province as a whole (FST 5 0.015,P 5 0.127 and FST 5 0.011, P 5 0.056, respectively) orwhen any possible geographical boundaries were tested,for example, eastern vs. western (FCT 5 0.017, P 5 0.097and FCT 5 0.029, P 5 0.096, respectively).
Phylogeographic analysis
Almost all the Y-chromosomes classified into the wide-spread R haplogroup in European populations belong tothe R1*-M173 subclade, being more frequently found forthe Western European populations (Capelli et al., 2006;Cruciani et al., 2002; Rosser et al., 2000; Semino et al.,2000), as well as in the Iberian populations (Adams et al.,2008; Alonso et al., 2005; Alvarez et al., 2009; Belezaet al., 2006; Bosch et al., 2001; Brion et al., 2004; Floreset al., 2004; Goncalves et al., 2005; Pardinas et al., 2012),analyzed so far.
The R1*-M173 frequency detected in the Zamora prov-ince (59.3%) is in accordance with values previouslyobserved in populations from adjacent geographical areas:Portuguese districts of Braganca (64%), Guarda (59.9%),and Vila Real (64.1%) (Beleza et al., 2006); and the Span-ish areas of Galicia (57%), Northwest Castile (62%)(Adams et al., 2008), and Asturias (61.9%) (Pardinaset al., 2012).
The I*-M170 haplogroup is also widespread in Euro-pean populations, and its distribution and posteriorexpansion and spread reflects its origin before the last gla-ciation (Rootsi et al., 2004; Semino et al., 2000). In theanalyzed Y-chromosomes of the Zamora province popula-
tion, the observed overall value of 8.2% is in the samerange as those values previously described in several Ibe-rian populations, for example, 6% (Adams et al., 2008),and 7.5% (Alonso et al., 2005).
Haplogroups J, G, and K
The J-12f2 haplogroup distribution over the Europeancontinent points out a Middle East origin associated withthe Neolithization process (Semino et al., 2004), with itshigher frequencies found in the Jewish and non-Jewishpopulation from Turkey (Behar et al., 2004; Hammeret al., 2000). Its presence in Iberia can be also assigned tothe presence of Jews and Arab introgressions in historicaltimes (as the J1-M267 subclade, previously described).
In the analyzed Y-chromosomes, this haplogroupaccounts for up to the 11.5% of the variability detected inthe Zamora province, a value similar to that previouslyreported for the Iberian populations (10%) (Adams et al.,2008; Alonso et al., 2005).
The J-12f2 haplogroup together with the G-M201 andK*-M9(xP*-M74) have been detected in high frequencies(69%) in Sephardic Jewish populations (Adams et al.,2008) and in a Northeastern Portuguese Crypto-Jewishcommunity (30.3%) (Nogueiro et al., 2010), with hap-logroup J-12f2 being the most prevalent (47.0% and36.8%, respectively). However, the value observed in theZamora province population (17.9%) is in the same rangeas the values previously detected for the neighboring pop-ulations of Northwest Castile (16%) in Spain (Adamset al., 2008) and Tr�as-os-Montes (18%) in Portugal (Belezaet al., 2006).
African lineages
The presence of African lineages in the Zamora prov-ince population was described by Alvarez et al. (2010),where mtDNA haplogroups L1b, L2b, L3b, M1, andU6a1a accounted for 5.7% of the total haplogroup compo-sition. The majority of these African lineages (80.2%) cor-responded to specific sub-Saharan haplogroups (L1b, L2b,and L3b). In this sense, the high sub-Saharan hap-logroups frequency in the southern regions of the Zamoraprovince, 18.2% in Sayago, and 8.1% in Bajo Dueroreported therein, have no parallels with any other ana-lyzed areas in Iberia, with the exception of Southern Por-tugal, where two municipalities showed particular highvalues, 22% in Alcacer do Sal and 8.7% in Coruche (Cer-ezo et al., 2012; Pereira et al., 2005; Pereira et al., 2010).
In contrast to the mtDNA results, no specific sub-Saharan haplogroups were found in the analyzedY-chromosomes of the Zamora province population.Regarding the North African ancestry, a specific set ofNorthwest African haplogroups have been described asmarkers of the Islamic rule period contribution to South-ern European populations, E1b1b1b-M81, E1b1b1a-b-M78 (showing allele 10 in DYS439 locus), and a subset ofJ1-M267 (Capelli et al., 2009; Cruciani et al., 2004; Fran-calacci and Sanna, 2008; Semino et al., 2004). In theZamora province, these haplogroups altogether accountfor 10.2% of the variation (5.5% for E1b1b1b-M81; 0% forE1b1b1a-b-M78—showing allele 10 in DYS439 locus—and 4.7% for J1-M267).
All 12 haplotypes corresponding to 13 individuals insidethe E1b1b1b-M81 haplogroup and none of the nine J1-M267 match the criteria for an ancestry compatible with
Y-CHROMOSOME VARIATION IN NORTHWEST IBERIA 5
American Journal of Human Biology
the Islamic rule period in Iberia (Supporting InformationTable 4). The values obtained for the three markers (5.5%for E1b1b1b-M81; 0% for E1b1b1a-b-M78, and 0% for J1-M267) are in the same range as those reported by Capelliet al. (2009) for 717 individuals in Spain (5.2%, 1.0%, and1.5%, respectively) using nine STR loci.
In an attempt to assign the origin of the selected Islamicrule period ancestry haplotypes found in the Zamora prov-ince to a specific country, ethnic/linguistic group, and popu-lation in North-West Africa, we focused on the haplogroupE1b1b1b-M81 inferred probabilities listed in Table 2. Thishaplogroup is common in the Northern African popula-tions, associated with the Imazighen ethnic group, withfrequencies of around 80% (Alvarez et al., 2009; Boschet al., 2001; Cruciani et al., 2004; Cruciani et al., 2002).
The country/ethnic group showing a higher probability ofbeing the source of Northwestern African haplotypes foundin the Zamora province population were Tunisian Berbers(14.7%), followed by Tunisian Arabs (13.6%), and MoroccanBerbers (11.6%), while the rest of the countries/ethnicgroups considered, taken together, accounted for 60.1% ofthe probability. When the analysis was performed at popu-lation level, probabilities were scattered among several Ber-ber populations from Tunis and Morocco. The resultsindicated the Tunisian Berbers from Jradou (10.2%) andthe Tunisian Berbers from Takrouna (9.7%) as the mostprobable candidates to be the source of the NorthwesternAfrican haplotypes compatible with an Islamic rule periodancestry found in the Zamora province population.
Overall, this work has made it possible to study of theimpact of recent historical events on the male gene pool ofZamora province, with an emphasis on the contributionresulting from the Islamic rule period in the Iberian Pen-insula that altered the genetic composition of the region.Considering the markers of such contribution, bothE1b1b1b-M81 and J1-M267 chromosomes were identified,although only the first ones were found with an ancestrycompatible with the Islamic rule period in Iberia. The dif-ferent behavior of E1b1b1b-M81 and J1-M267 chromo-somes can be explain by the complex history of the formerclade showing different genetic backgrounds in Eurasianand Arabic populations, according to Tofanelli et al.(2009). In contrast, the E1b1b1b-M81 clade, as previouslystated, is almost restricted to Northern African popula-tions matching the present area of distribution of the Ima-zighen ethnic group. These results support the entranceof Northern African Y-chromosomes in recent times, incontrast with pre-historical events.
The interbreeding between Christians and Muslims inthis period occurred in an imbalanced way, involving mainlyChristian males, due to cultural constrictions (Pereira et al.,2005). Therefore, the relocation of moriscos in the northernand western parts of Spain, at the end of the 16th century,after the Revolt of Las Alpujarra, had been hypothesized tobe the explanation for the irregular distribution of the NorthAfrican ancestry proportions in Iberia, based on the pres-ence of the E1b1b1b-M81 haplogroup (Adams et al., 2008).In this context, the presence of three different groups ofmoriscos, settled in the Zamora province territory precedingtheir final expulsion in the beginning of the 17th century,has been described: (i) descendants of those mud�ejares bap-tized in 1502; (ii) moriscos from Granada, deported in 1570;and (iii) moriscos linked to domestic service (Martin, 2003).Clearly, these groups have left a mark on the current genepool of the Province. It may have been that the expulsion,
unlike in other parts of the Peninsula, was not carried outas forcefully.
ACKNOWLEDGMENT
The authors are very grateful to sample donors and allthe workers of regional health centers of the Zamora prov-ince for their selfless support in the sampling process.
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