Al-Andalus in the Genome: Why Modern Spaniards Have So Little North African Ancestry

Modern Spaniards have far less North African ancestry than popular intuition assumes. Modelled on the Davidski Standard G25 Calculator (Calculator 2 on ExploreYourDNA), which uses Taforalt (Iberomaurusian Morocco, around 15,000 BP) as the clean reference for endemic ancient North African ancestry, the average Spanish region carries only 2.5 percent Taforalt. The Basque Country (Pais Vasco) sits at exactly 0.0 percent. Catalonia, northern Aragon, Burgos, Biscay, La Rioja, and most of the Catalan provinces fall between 0.4 and 1.4 percent. Even Andalusia, which preserves the strongest signal, sits at 4.6 percent, and Extremadura at 5.4 percent. Only the Canary Islands break out of this pattern at 9.6 percent, and that signal reflects the autochthonous Guanche population from before Spanish colonization, not the Andalusi conquest. Even more strikingly, a substantial fraction of what looks like North African ancestry in NNLS-based models is not Andalusi at all. It is the genetic echo of a prehistoric cross-Strait flow documented by Fregel et al. 2018: the Iberian Cardial farmers who crossed Gibraltar around 5500 BCE made the Late Neolithic Moroccans roughly 50 percent European Neolithic in autosomal ancestry, which means that when modern Spaniards are modelled against composite Berber references, part of the signal recovered is not Andalusi at all but a shared Mediterranean Neolithic substrate that predates al-Andalus by 6,000 years. The Taforalt-based model used here avoids that contamination by anchoring on a pre-Neolithic Moroccan sample. The Andalusi pulse is real, but it is smaller, older, and more regionally restricted than the cultural impact of al-Andalus would suggest.

1. An eight-century historical horizon

The history of al-Andalus begins in April 711 CE with the landing of Tariq ibn Ziyad and his Berber-Arab contingent at Gibraltar. In less than seven years, the Visigothic kingdom is destroyed and almost the entire Iberian Peninsula is integrated into the Umayyad Caliphate of Damascus, which would transform into the independent Emirate and then Caliphate of Cordoba. The borders then shift continuously northward during the Christian Reconquista: Toledo falls in 1085, Cordoba in 1236, Seville in 1248, and finally Granada in 1492. Between the conquest and the final expulsion of the Moriscos in 1609 to 1614, this is nine centuries of continuous interaction between Christian, Jewish, and Muslim populations on Iberian soil.

The genetic question can be put in a few words: how many people actually crossed the strait? What was the precise nature of the admixture? And how much of this North African ancestry survives today in the Spanish and Portuguese gene pool? The Andalusi written sources suggest a minority Arab elite, a larger Berber mass, captured Slavic populations, Sub-Saharan slaves via trans-Saharan routes, and a Hispano-Roman autochthonous population that gradually adopted the language and religion of the conquerors. But the numbers were impossible to verify before the arrival of paleogenetics.

2. The classic historiographical error: North African ancestry is older than 711

For a long time, the presence of North African ancestry in the Iberian Peninsula was spontaneously attributed to the Islamic period. This was an error. The major study by Olalde et al. published in Science in 2019, which analyzes 271 ancient Iberian genomes spanning 8,000 years, established for the first time that North African signatures could be detected in Iberia already during the Roman period, and even, more episodically, in the Bronze Age. The Reich preprint 2024 on 248 Iberian individuals from periods 100 to 800 CE (already documented in part by Lazaridis) confirmed the magnitude of this Roman Mediterranean input, and added an explicit North African signal, particularly marked in central and southern Iberia.

But the most striking observation comes from a single burial. The site of Montefrio in the province of Granada, dated between 400 and 600 CE, that is, in the heart of the Visigothic kingdom and several generations before the Muslim arrival, contains individuals categorically "Visigothic" on the cultural level but who carry 29 percent North African ancestry (Rodriguez-Varela et al. 2024 Science Advances, the principal Las Gobas study with comparison to the Olalde 2019 data). This figure is extraordinary. It means that Berber-Mediterranean populations were already widely represented in southern Iberia before the Islamic conquest.

The most plausible explanation combines three pre-Islamic sources:

1. The Phoenician and Carthaginian expansion (8th century BCE to 2nd century BCE), which founded Gadir (Cadiz), Malaga, Cartagena, and several coastal trading posts in southern Iberia. Mitochondrial analyses of the Punic burials of Cadiz (Gomes et al. 2023 MDPI Genealogy, based on 16 individuals) find HV0, H, and L3b lineages that draw their origin from the Levant and the Maghreb. More broadly, the Ringbauer et al. 2025 study on the Punic populations showed that these Punic communities were cosmopolitan and integrated a substantial share of local and North African ancestry.
2. Mauretanian and Numidian expansion during the Roman Republic and Empire, particularly after the fall of Carthage in 146 BCE. Mauretania Tingitana (modern Morocco) was politically integrated with Hispania Baetica (modern Andalusia) and formed with it a single administrative, commercial, and demographic space. The Algeria_NumidoRoman_Berber.SG sample documents a Berber population with an already Mediterranean profile during this period, capable of migrating to southern Iberia without any institutional obstacle.
3. The Pardo-Seco et al. 2025 preprint study on 453 modern Galician genomes (Spanish National DNA Bank) identifies a male-biased pre-Islamic North African ancestry. This suggests ancient Mediterranean commercial and military networks, plausibly dating back to the Punic and Numido-Roman presence, rather than a single Arab-Berber pulse in the 8th century. This finding opens a new era of interpretation: the North African share of Iberians is not a monolithic Islamic input but a superposition of successive layers spanning more than two millennia.

3. The Neolithic cross-Strait flow: when Iberia colonized North Africa, not the other way around

The single most important finding for understanding modern Iberian ancestry is also the most counterintuitive. Long before any Arab, Berber, Phoenician, or Roman ever set foot on Iberian soil, a major demographic flow had crossed the Strait of Gibraltar, but in the opposite direction. Around 5500 BCE, Iberian Cardial farmers, descendants of the Anatolian Neolithic, crossed the eight nautical miles of the strait and settled in northern Morocco. Within a thousand years, the Late Neolithic Moroccan population had been substantially transformed.

Fregel et al. 2018 in PNAS (republished in 2018, with subsequent confirmation by Simões et al. 2023 in Nature) documented this transformation directly through three ancient samples. IAM (Ifri n'Ammar, Early Neolithic Morocco, around 5000 BCE) preserves an endemic Maghrebi component identical to the Iberomaurusian substrate, with no European or Sub-Saharan input. TOR (Torre Cardela, Early Neolithic southern Iberia, around 5000 BCE) shows a pure European Neolithic profile of Anatolian farmer ancestry. KEB (Kelif el Boroud, Late Neolithic Morocco, around 3000 BCE) is the critical sample: it sits exactly halfway between IAM and TOR, with approximately 50 percent European Neolithic ancestry and 50 percent endemic Maghrebi ancestry. Modern Mozabites and northern Moroccans inherit this admixed profile directly, with an additional Sub-Saharan layer that Fregel et al. dated to around 1200 years ago (8th to 9th century CE), coincident with the trans-Saharan trade routes of the early Islamic period.

This finding also reframes the entire question of what "North African" ancestry means in an Iberian context. The Maghreb and Iberia have been autosomally connected for at least 7,500 years through the narrow strait that separates them. The Cardial farmers crossed into Morocco around 5500 BCE; the Phoenicians established trading networks on both shores from 800 BCE onward; the Numido-Roman administration unified the Mauretania Tingitana and the Hispania Baetica into a single province from 27 BCE to the 4th century CE; the Vandals crossed into North Africa in 429 CE; the Umayyads crossed back in 711 CE; the Almoravids crossed in 1086; the Almohads in 1147; and the Moriscos crossed back to North Africa in 1609. Each crossing left a trace, and many of the traces overlap on the same autosomal axes. Disentangling them requires careful ancient DNA, which the studies of the last decade have finally provided.

The bottom line: when a modern Andalusian shows 10 percent "North African" ancestry, perhaps half of that is Andalusi (post-711 Berber admixture), a smaller fraction is Roman-era (Mauretania Tingitana commercial integration), and the remainder is the deep Neolithic substrate shared across the Strait for 7,500 years. The Andalusi contribution is real, but it is only part of a longer story.

4. The genetic profile of al-Andalus: what Islamic burials show

Before 2019, there was practically no ancient DNA from Iberian Islamic individuals. Three major publications changed the picture between 2019 and 2026: Olalde et al. 2019 (two individuals from Granada, the 10th and 16th century), Oteo-Garcia et al. 2025 (twelve individuals from the Kingdom of Valencia, from the 7th to the 17th century), and Rodriguez-Varela et al. 2026 (thirteen individuals from the Maqbara of Madina Yabisa in Ibiza, 950 to 1150 CE). The picture that emerges from these three combined corpora is remarkably coherent.

5. Quantification: how many effective Maghrebis?

Combining the autosomal data from al-Andalus with modern references allows us to propose a quantified estimate of the demographic contribution. The standard method is qpADM, which models the Iberian Islamic population as a mixture of two or three sources: Hispano-Roman autochthonous, Maghrebi Berber (Mozabite or Northern Moroccan Berbers), and possibly a Sub-Saharan component. Here is the typical decomposition for the main sequenced populations:

The picture from the Davidski Standard G25 Calculator is striking. Twenty out of 33 Spanish regional populations carry less than 3 percent Taforalt ancestry. Only six populations sit above 4 percent: Andalucia (4.6%), Murcia (4.2%), Asturias (4.8%), Galicia (4.8%), Castilla y Leon (5.2%), and Extremadura (5.4%). The Canary Islands are an outlier at 9.6% that has nothing to do with al-Andalus (it reflects the pre-colonization Guanche substrate). Even Andalusia, the historical heart of al-Andalus and the last region to fall to the Reconquista in 1492, carries less than 5 percent of the clean Taforalt signal.

The Basque Country (Spanish_Pais_Vasco) sits at exactly 0.0 percent Taforalt. This is not approximation or rounding error: it is the literal output of the Davidski Standard G25 model. The Basques are a true pre-Roman capsule, never significantly admixed with North African populations, neither in the prehistoric Cardial period nor during al-Andalus. Catalonia (2.8%) and most of its sub-regions (Barcelones 1.0%, Catalunya Central 0.6%, Lleida 1.2%, Girona 1.4%, Penedes 1.4%, Peri-Barcelona 1.4%, Pirineu 1.8%, Terres de l'Ebre 1.2%) sit in a tight cluster of 0.6 to 2.8 percent. Northern Aragon (0.4%), Burgos (0.8%), Biscay (1.4%), and La Rioja (1.4%) are at the same level. None of these regions carries detectable Andalusi admixture above the noise floor of the model.

Four observations emerge from this empirical picture. First, the North African contribution was already significant in the south before 711, and the Islamic conquest amplified a pre-existing signal rather than introducing it. Second, during the Islamic period itself, individuals locally buried in Muslim cemeteries show 35 to 50 percent North African ancestry, but they represent a minority population that did not demographically replace the Hispano-Roman majority. Third, in modern populations, the post-711 signal that survives is small: a 2.5 percent national average and a maximum of 5 to 6 percent in the most affected regions.

Fourth, the Basques and Catalans have essentially no Andalusi ancestry at all. The Basque Country, which was never under sustained Islamic control, sits at zero percent on the Davidski Standard G25. Catalonia, briefly held by the Umayyads in the 8th century before being incorporated into the Spanish March of Charlemagne in 801, sits at 1 to 3 percent. Galicia, never conquered beyond ephemeral raids, sits at around 4.8 percent, with the Pardo-Seco 2025 study showing that this small signal is largely pre-Islamic and male-biased, consistent with Phoenician and Roman networks rather than Andalusi admixture. The "Andalusi" component of modern Spaniards is therefore concentrated almost entirely in the historically Islamic territories: the lower Guadalquivir basin, Extremadura, the southern meseta, and parts of the Levante. North and northwest of an imaginary line running from Lisbon to Zaragoza, the signal is so small that it cannot reliably be distinguished from the ancient cross-Strait Neolithic substrate.

6. The two-pulse model confirmed

The North African demographic contribution in Iberia did not occur in a single wave. Historical sources distinguish three principal phases: the initial conquest of 711 to 740 dominated by Berbers (and a minority Arab elite), the Almoravid pulse of 1086 to 1147 (Sanhaja Berbers from Mauritania and the Western Sahara), and the Almohad pulse of 1147 to 1212 (Masmuda Berbers from the Moroccan High Atlas). For a long time, it was unclear whether these pulses were limited military events (a few thousand soldiers) or genuine significant demographic pulses.

The 2026 Nature Communications study on Ibiza provides the first direct confirmation of a two-pulse model. The method uses the decay of local ancestry covariance along the genome, which allows dating the admixture in generations before the death of each individual. For the Ibiza population averaged at 1080 CE, the main admixture goes back to 869 CE (confidence interval 863 to 875), about eight generations earlier. This corresponds exactly to the Umayyad conquest of Ibiza in 902 CE and the Berber-Arab settlement phase immediately following. Two individuals dated after 1115 CE, by contrast, show more recent admixture, compatible with the Almoravid capture of Mallorca in 1115 to 1116 CE and the subsequent Sanhaja Berber pulse.

7. The Sub-Saharan bridge: Senegambia and Chad

One of the most striking discoveries of the 2026 Nature Communications paper on Ibiza is the presence of two direct Sub-Saharan individuals, whose precise geographic origins could be traced. Individual s.117 carried Y haplogroup E1b1a1a1a and mitochondrial L3e1c. His closest autosomal affinities are the Sara and Laal populations from present-day southern Chad, who speak a Nilo-Saharan language and an isolate language, respectively. Individual s.197 carried mitochondrial L3b2 and clusters with the Bedik populations of eastern Senegal and the Mandinka of Gambia.

These two origins reflect the two main routes of medieval trans-Saharan trade. The western route, from the Sahel of southern Mauritania and the inner Niger delta, fed the caravans toward Sijilmasa and then Atlantic Morocco. The central route, from the Lake Chad basin and the southern Tibesti mountains, led via the Kanem-Bornu toward Tripoli and Kairouan. Medieval Arabic sources abundantly document these exchanges: military slaves (the so-called "Sudan" contingent in the Fatimid army), court eunuchs, agricultural slaves, but also free merchants and mercenary soldiers.

Individual s.117 has 12 to 14 Sub-Saharan generations before him, which places his direct Sub-Saharan ancestor in the 8th or 9th century. This is a chronology compatible with the military integration of Sub-Saharan mercenaries into the Fatimid and then Umayyad armies. Individual s.197, however, has 6 to 7 Sub-Saharan generations back, which places him later, perhaps via the Almoravid trade that explicitly took up the trans-Saharan routes in the southwest Sahara. The two trajectories testify that al-Andalus was connected to the rest of Africa through multiple networks, and not just through a narrow Tangier-Tarifa strait.

8. The Morisco expulsion of 1609 and the genetic erasure of eastern Iberia

The Oteo-Garcia et al. 2025 study (Genome Biology), based on twelve individuals from the Kingdom of Valencia covering the 5th to the 17th century, provides the first direct evidence that the expulsion of the Moriscos in 1609 had a measurable genetic impact. The pre-1609 burials (both Christian and Muslim) show a present and persistent North African component. The post-1609 burials show a drastic drop in this component. The principal author interprets this contrast as the result of the mass expulsion (approximately 275,000 people deported to the Maghreb in five years) followed by repopulation with Christians from more northern regions (Castile, Aragon, Catalonia), who brought a signature poor in North African ancestry.

The asymmetry between north and south is therefore not only geographic: it is also historical. The south (Andalusia, Extremadura) preserves a stronger signature because the Reconquista was later there (Granada 1492) and because Christian repopulation was never demographically total there. Eastern Iberia (Valencia, Aragon) once preserved a comparable signature, but the Morisco expulsion partially erased it. The northwest (Galicia, Asturias, Basque Country) was almost never under direct Islamic control and therefore never accumulated this signature.

9. The Y-chromosomal component: Berber and not Arab

A recurring question on genealogy forums is whether the North African Iberian component is "Arab" or "Berber". The autosomal answer does not always distinguish the two well, since Maghrebi Arabs are themselves largely Berberized on the autosomal level. Y-chromosomal analysis, by contrast, offers a direct discrimination.

In the 2026 Ibiza study, of the nine men analyzed, six carry a typically Berber Y haplogroup (five E1b1b1b1a1, one E1b1b1a1a1c2). Only one carries a Sub-Saharan haplogroup (E1b1a1a1a). One carries a Western European haplogroup (R1b1a1b1b3). None carries typically Arab Near Eastern haplogroups such as J1-FGC11 or J2-M172 at high frequencies. This means that the male component of the Islamic population of Ibiza was essentially Maghrebi Berber, consistent with the historical sources that describe a colonization led by Ait Magrawa and Sanhaja clans with a minority Arab elite.

This observation probably extends to all Islamic Iberia. The "Arab" contribution sensu stricto to the modern Iberian gene pool is small, perhaps less than 1 percent. The "Berber" contribution is more substantial, between 4 and 12 percent depending on the region. The trade routes and the armies brought a broader diversity (Sub-Saharans, Slavs, Balkans) that appears in the medieval burials, but without leaving a durable signal proportional to their historical visibility.

10. Summary: the quantitative picture

The table below combines the qpADM-derived North African percentages for ancient samples (Olalde 2019, Rodriguez-Varela 2024, Rodriguez-Varela 2026) with the precise Taforalt percentages from the Davidski Standard G25 Calculator (Calculator 2 on ExploreYourDNA) for modern populations.

11. The fate of the deported Moriscos: a circle that closes

The Morisco expulsion between 1609 and 1614 deported approximately 275,000 people to North Africa, mainly Morocco, Algeria, Tunisia, and Libya. This population, culturally Hispanicized for more than a century (many Moriscos spoke only Castilian and had never learned Arabic), gradually integrated into the Maghrebi populations. Today, in cities such as Tetouan, Chefchaouen, Sale, and Tunis, one finds Morisco families identifiable by their family names (Andaluci, Granadi, Cordobi), their domestic architecture, and certain food practices. The genetic signal of these Morisco communities in the Maghreb is intermediate between the Iberian Christian profile and the Maghrebi Berber profile, exactly as one would expect for descendants of converted muladis living in Spain before 1609.

This movement completed the cycle begun in 711: the descendants of the Berber conquerors had spent eight centuries mixing with the Hispano-Roman populations before being, partially, sent back to North Africa. The demographic round trip wove between the two shores of the western Mediterranean a genetic kinship that far exceeds the present political border.

12. G25 coordinates (Global25 scaled)

The following coordinates correspond to the main populations cited in this article. Copy them into Vahaduo, the K248 calculator by Karl Hogstrom, the Standard G25 Calculator by Davidski, the Migration Era Calculator (Calculator 186 on ExploreYourDNA), or the Modern World Regions Mythbuster (Calculator 173) for your own modeling.

Spain_IA,0.1258262,0.1492827,0.0583851,0.0049625,0.0602349,-0.0044623,-0.0022645,0.0031048,0.0336535,0.0464537,-0.0050636,0.0132018,-0.0238533,-0.0138374,0.0089698,0.0056533,0.006626,0.0005185,0.0040911,-0.0026263,0.0052294,-0.0004945,-0.0051203,-0.0136163,-0.0022753
Spain_LBA,0.124067,0.1506367,0.0541797,0.0005383,0.059498,-0.0016733,-0.00376,0.004923,0.0375643,0.046956,-0.0043307,0.0025977,-0.026313,-0.0164687,0.0050673,0.0034033,-0.0042157,-0.0034203,-0.004274,0.0020843,0.0122703,-0.003627,-0.009942,-0.016468,0.0007583
Spain_Roman,0.088782,0.147252,0.03017,-0.025517,0.044008,-0.021753,-0.001645,0.003923,0.029247,0.037176,-0.002923,0.001499,-0.005798,-0.010872,0.00665,-0.004641,-0.012256,-0.005828,-0.01081,0.00025,-0.000499,-0.007666,0.003204,-0.007471,-0.005389
Spain_Roman_oAfrica,0.0724673,0.151991,0.0143307,-0.0404827,0.03416,-0.0171053,-0.007755,0.0006153,0.0295197,0.032438,-0.0023273,0.0062943,-0.0044103,-0.0147257,0.0040263,0.0050823,0.0139077,-0.0019003,-0.0074163,-0.001709,-0.0017467,-0.004699,0.0043957,-0.0041773,-0.001916
Spain_Visigoth,0.1272542,0.1358778,0.0463104,0.02261,0.0377302,0.0069724,0.00658,0.0029076,0.0075264,0.0115536,-0.0050666,0.008782,-0.0121604,-0.0059452,0.0059446,0.0051178,0.0050328,0.0032434,-0.0004274,0.0055778,0.0060892,0.0015828,-0.002539,0.0017352,-0.0021316
Spain_Visigoth_Granada,0.0795336,0.1473786,0.0188089,-0.0245884,0.034814,-0.011783,-0.007726,0.0023654,0.0322638,0.0372444,-0.0026998,0.0055451,-0.0060206,-0.0095821,0.0069896,-0.0072428,-0.0064376,0.0002691,-0.0154609,-0.0019851,0.0009359,-0.0106341,0.0048375,-0.008239,-0.001931
Spain_Islamic,0.0967497,0.1452207,0.0296042,-0.0178188,0.0366733,-0.0066467,-0.0057183,-0.0017692,0.0246452,0.0283378,0.0004873,0.0081677,-0.0091427,-0.015666,0.006899,0.00579,0.0045852,-0.008847,-0.0114385,-0.0002083,0.0020797,-0.002267,0.0017257,-0.0035142,0.0007785
Spain_Islamic_Almohade,0.068294,0.147252,0.027153,-0.025194,0.035699,-0.014781,-0.011045,0.004615,0.031292,0.036083,0.003085,0.004646,-0.008028,-0.013074,0.006243,-0.005701,0.005998,0.000253,-0.013575,-0.001251,-0.006863,-0.025349,0.008997,-0.003012,-0.004071
Spain_Islamic_Zira,0.084229,0.1416665,0.0092395,-0.0272935,0.0273895,-0.0188255,-0.0071675,0.0021925,0.024236,0.024784,0.0014615,-0.003297,-0.003345,-0.002408,0.009297,-0.0025855,-0.001043,-0.003674,-0.00905,0.0070035,-0.0018715,-0.010696,0.001048,-0.0047595,0.000599
Spain_Medieval,0.1154168,0.1421738,0.0356754,-0.0032946,0.0360068,0.000223,-0.0048882,0.003323,0.0278562,0.0347706,-0.0040922,0.007763,-0.0126658,-0.009496,0.0049674,-0.0024128,0,-0.0054224,-0.0027654,-0.0037518,0.0046918,0.002869,-0.0021444,-0.0029642,0.000024
Spain_Carolingian,0.1212215,0.1497905,0.042992,0.0075905,0.054164,-0.003765,-0.0005875,0.005538,0.0270995,0.0268795,-0.001786,0.003822,-0.005426,-0.0070875,0.008754,0.0076905,-0.0097785,0.0048775,-0.0055935,0.0097545,-0.002745,0.0087795,-0.0074565,0.006748,-0.0011975
Algeria_NumidoRoman_Berber.SG,0.0916275,0.150298,-0.024324,-0.0521645,0.008155,-0.021335,0.0034075,-0.0003465,0.006954,0.021048,0.0022735,0.003822,-0.0039395,0.0001375,-0.002375,-0.0028505,0.005411,-0.002154,-0.0000630,-0.005565,-0.005116,-0.005626,0.00228,0.001145,0.0044305
Morocco_LN.SG,0.019919,0.1457285,-0.00264,-0.0931855,0.0401615,-0.0474115,-0.0217385,0.004615,0.081094,0.0359005,0.006739,0.013188,0.014123,-0.018717,0.0007465,-0.0017235,0.0158415,-0.0064615,-0.0331215,0.0190715,-0.0101695,-0.023123,0.008196,-0.010664,0.0001795
Morocco_EN.SG,-0.1735805,0.092413,-0.026398,-0.082365,0.030621,-0.0602405,-0.0794335,0.020538,0.1517565,0.005376,0.0208665,-0.025702,0.0747765,-0.045966,0.0671815,-0.0325505,0.013364,-0.05701,-0.149455,0.0322025,-0.0400545,-0.117223,0.0815285,-0.009519,0.0212555
Morocco_Iberomaurusian,-0.189857,0.0812424,-0.0233816,-0.085918,0.026897,-0.0562244,-0.0688578,0.0189222,0.1556838,0.0023324,0.0228318,-0.0328806,0.0757278,-0.0494342,0.0694074,-0.035799,0.007719,-0.0649408,-0.1416618,0.0393438,-0.037908,-0.1254826,0.0707936,-0.0144358,0.0191596
Mozabite,-0.065966,0.135435,-0.004183,-0.072837,0.025907,-0.033277,-0.026161,0.010678,0.06224,0.030259,0.006592,-0.006812,0.02236,-0.016496,0.016422,-0.016309,-0.002714,-0.022309,-0.044457,0.008771,-0.014809,-0.037579,0.024857,-0.004338,0.00559
Moroccan_North,-0.029973,0.137322,-0.003038,-0.0674,0.028057,-0.031917,-0.024454,0.005051,0.060982,0.032732,0.005909,-0.006552,0.018591,-0.01471,0.01514,-0.010563,0.00126,-0.017983,-0.040747,0.009296,-0.012194,-0.03463,0.021438,-0.005576,0.004397
Moroccan_South,-0.184464,0.119895,0.000731,-0.056929,0.023966,-0.026826,-0.032196,0.01523,0.053815,0.028543,0.006059,-0.006819,0.022736,-0.017332,0.018102,-0.015331,0.001092,-0.018924,-0.040789,0.00852,-0.014825,-0.038456,0.024072,-0.003494,0.005494
Berber_Algeria,-0.293664,0.105158,0.001999,-0.040068,0.014449,-0.012341,-0.036673,0.021057,0.026936,0.021531,0.005757,-0.004526,0.021318,-0.007432,0.011428,-0.00883,0.003123,-0.011079,-0.023053,0.00499,-0.007362,-0.019636,0.012177,-0.000361,0.002652
Saharawi,-0.095421,0.131341,-0.009664,-0.080683,0.024171,-0.035396,-0.032882,0.00899,0.077336,0.028884,0.010731,-0.009367,0.030562,-0.015569,0.023434,-0.014773,-0.003803,-0.024884,-0.048598,0.012443,-0.015078,-0.041553,0.027869,-0.002842,0.007589
Senegal_Bedik,-0.61436,0.063534,0.019422,0.014071,0.00075,0.009064,-0.035178,0.038436,-0.032136,0.023292,0.003004,-0.000796,0.017142,-0.001075,0.01252,-0.009969,0.009632,-0.001679,-0.00363,-0.000289,-0.001848,-0.003524,0.00104,-0.001988,0.001078
Chad_Sara,-0.575325,0.060562,0.005948,-0.009426,0.000672,-0.002383,-0.035978,0.032086,0.056374,-0.06756,-0.013345,0.017085,-0.024421,-0.001614,0.010574,-0.01658,0.014182,-0.013141,0.013158,-0.014945,-0.001259,0.000691,-0.000751,-0.003111,0.004681
Spanish_Andalucia,0.108132,0.146076,0.035707,-0.003434,0.045256,-0.005857,-0.00193,0.00266,0.024715,0.031162,-0.002154,0.007272,-0.013207,-0.011408,0.010243,-0.002498,-0.006176,-0.0011,-0.004261,-0.002133,0.002929,-0.001302,-0.001972,-0.005334,0.001885
Spanish_Extremadura,0.105096,0.14996,0.033061,-0.001184,0.040931,-0.002789,-0.003995,-0.001,0.024679,0.031223,-0.001299,0.005046,-0.010604,-0.012248,0.007555,0.002608,-0.002347,-0.003294,-0.006411,0.000417,0.002121,-0.00474,-0.001479,-0.002771,0.001437
Spanish_Castilla_Y_Leon,0.107753,0.143867,0.040477,-0.002153,0.043803,0.001859,-0.001723,0.004615,0.028429,0.029218,-0.002328,0.007843,-0.012091,-0.012019,0.01226,-0.006541,-0.00678,-0.001731,-0.004525,-0.002293,0.000291,-0.000907,0.001315,-0.002571,-0.002754
Spanish_Galicia,0.108765,0.146462,0.041064,-0.001651,0.041204,-0.0000930,-0.005457,0.002423,0.024713,0.030029,-0.002129,0.005737,-0.012611,-0.012157,0.011144,0.000589,-0.004237,-0.002161,-0.005042,-0.001007,0.000873,-0.002899,-0.000808,-0.003682,0.001304
Spanish_Valencia,0.117997,0.144629,0.040855,-0.000888,0.04647,-0.001441,-0.001998,0.001634,0.023162,0.033258,-0.003004,0.00833,-0.012859,-0.01234,0.009602,-0.000851,-0.004694,-0.001721,-0.001236,-0.000917,0.005574,-0.00137,-0.002044,-0.005141,0.002056
Spanish_Cataluna,0.114582,0.146236,0.045883,0.002369,0.047188,0,-0.002037,0.002384,0.022361,0.030494,-0.001895,0.008592,-0.016006,-0.010643,0.008867,0.001591,-0.000652,-0.001647,-0.001131,-0.000959,0.006197,-0.005729,-0.003903,-0.001928,0.000958
Spanish_Pais_Vasco,0.128241,0.151652,0.056317,0.008075,0.052112,0.002417,0.000235,0.002923,0.027747,0.039849,-0.0059,0.009342,-0.02106,-0.012065,0.018413,-0.002475,-0.012343,0.002872,0.002221,-0.006587,0.007736,-0.002432,-0.006532,-0.006748,0.003672
Spanish_Canarias,0.081294,0.145702,0.030269,-0.012903,0.037837,-0.006224,-0.006494,0.000814,0.031604,0.029052,-0.000496,0.005261,-0.007175,-0.013617,0.011022,-0.002198,-0.002738,-0.003487,-0.010843,0.000987,0.000604,-0.00643,0.001641,-0.003418,0.001702
Basque_Spanish,0.126424,0.148739,0.055679,0.00879,0.05545,0.000249,-0.001754,0.0000250,0.029539,0.042923,-0.005214,0.010801,-0.024986,-0.019493,0.015807,0.002614,-0.00563,0.003172,-0.002375,-0.001791,0.008819,0.002204,-0.006479,-0.008654,0.00115
Portuguese,0.106174,0.144611,0.036007,-0.004432,0.042137,-0.004049,-0.003741,0.00276,0.025598,0.029741,-0.000734,0.007421,-0.012737,-0.011263,0.012557,-0.000398,-0.001132,-0.000887,-0.005762,-0.000245,0.001138,-0.002572,0.001301,-0.001133,-0.000105
Algerian,-0.068057,0.13278,-0.007165,-0.067736,0.021222,-0.030074,-0.02212,0.007442,0.053031,0.025095,0.005508,-0.00617,0.020856,-0.01386,0.013023,-0.010171,-0.003357,-0.016401,-0.031644,0.00716,-0.009639,-0.028291,0.018189,-0.000266,0.001292
Moroccan,-0.085367,0.130213,-0.012822,-0.070881,0.021132,-0.03294,-0.027783,0.009769,0.055403,0.024399,0.009509,-0.009025,0.02699,-0.014466,0.016302,-0.006188,-0.002767,-0.017033,-0.038422,0.009435,-0.009844,-0.029512,0.020911,-0.001125,0.005921
Tunisian,-0.04354,0.137322,-0.013608,-0.075208,0.018225,-0.033892,-0.024196,0.005436,0.057091,0.024399,0.005508,-0.008692,0.024085,-0.014405,0.011875,-0.005329,-0.005298,-0.018245,-0.038359,0.009310,-0.010013,-0.029512,0.022499,-0.001606,0.005921
Libyan,-0.047686,0.130949,-0.021933,-0.080955,0.008973,-0.034568,-0.020953,0.003024,0.052067,0.009822,0.006136,-0.012392,0.029224,-0.004998,0.008522,-0.000509,-0.003788,-0.009575,-0.020118,0.011269,-0.002811,-0.013263,0.009399,0.000799,-0.000296
Druze,0.088782,0.140143,-0.048875,-0.072417,-0.013172,-0.023817,-0.001763,-0.004061,-0.001391,0.00687,0.005408,-0.003492,0.007522,0.0000830,-0.006542,0.007398,-0.0000130,0.000899,0.00455,-0.002376,-0.004205,0.002003,-0.001146,0.000374,0.00309
Lebanon_IA3.SG,0.0879281,0.15106,-0.0490729,-0.0918128,-0.0102324,-0.0320375,-0.0045531,-0.009288,0.0108651,0.0133488,0.0070232,-0.0040839,0.0111311,0.0019781,-0.0098059,0.0023701,0.0016461,-0.0003326,0.0031268,0.0003438,0.0026984,0.0054406,-0.0038975,-0.0026359,-0.0047451
Israel_IA,0.084229,0.147252,-0.063356,-0.09367,-0.016311,-0.047969,-0.008695,-0.003923,0.01084,0.009294,0.008607,-0.005995,0.022596,0.005367,-0.008279,0.001458,-0.024773,0.006081,0.007416,-0.00988,0.003119,-0.002844,-0.002958,-0.001566,-0.005748

13. Three transversal lessons

The genetic history of al-Andalus illustrates, perhaps better than any other region in the world, three general principles of population paleogenetics.

First lesson: culture does not follow genetics in 1:1 proportion. Al-Andalus profoundly transformed the culture, language, urbanism, agriculture, cuisine, architecture, and institutions of the Iberian Peninsula for eight centuries. Yet the effective North African demographic contribution represents about 5 to 15 percent of modern ancestry, and remains concentrated in the south. Modern Castilian contains about 4,000 words of Arabic origin (azulejo, alcazar, almohada, ojala, hasta, aceite), but these words do not reflect the magnitude of demographic replacement: they reflect the intensity of asymmetric cultural exchanges between a politically dominant elite and a numerically dominant Hispano-Roman majority. This is the exact opposite of the Anglo-Saxons in Britain, who imposed their language but also replaced 50 to 90 percent of the local gene pool.

Second lesson: migratory pulses are measurable. Admixture dating by decay of local ancestry covariance, used in Rodriguez-Varela et al. 2026, now allows us to quantify in generations the moment when each mixture occurred. For Islamic Ibiza, two distinct pulses are identified: one around 869 CE (corresponding to the Umayyad conquest of 902 CE) and one after 1115 CE (corresponding to the Almoravid capture of Mallorca). This is the first time we are able to discriminate so clearly two distinct historical phases of a single period in the genome of a single population.

Third lesson: political expulsions leave genetic scars. The Morisco expulsion of 1609 to 1614 is not only an event of Spanish political history. It is also the only documented case, to our knowledge, where a relatively recent political event (less than 500 years ago) actually reduced the share of an identifiable ancestry in the resident population. In almost all other historical cases, "expulsions" leave a substantial part of the population on site (converted Jews, converted Muslims, etc.). In eastern Iberia, the contrast pre-1609 and post-1609 in Christian burials is sharp enough to be measured directly. This reminds us that political decisions, even after centuries of integration, can actually modify the gene pool of a region. Paleogenetics allows us to quantify what was previously only a historian's intuition.

14. Conclusion

Al-Andalus is not a historical epiphenomenon. Its duration, its political and cultural intensity, the scale of its administrative and commercial reach make this period one of the most formative episodes of Iberian history, comparable to Romanization by its scope and to Christianization by its identity depth. But on the genetic level, the effective contribution to the modern gene pool is remarkably modest. The Davidski Standard G25 Calculator on ExploreYourDNA, modelled with Taforalt as the clean reference for ancient North African ancestry, returns an average of only 2.5 percent across 33 Spanish regional populations. The Basque Country sits at exactly 0.0 percent. Catalonia, northern Aragon, Burgos, Biscay, and La Rioja all sit between 0.4 and 1.4 percent. Even the most strongly affected regions (Andalucia 4.6%, Extremadura 5.4%, Galicia 4.8%, Castilla y Leon 5.2%) carry less than 6 percent. In every Spanish mainland region, the autochthonous European base (Anatolian Neolithic + WHG + Yamnaya steppe) represents 94 to 100 percent of the autosomal model output.

Equally important, even this small residual signal is partly older than al-Andalus. The cross-Strait Cardial flow documented by Fregel et al. 2018 made the Late Neolithic Moroccans roughly 50 percent European Neolithic by 3000 BCE. The Mediterranean Sea between the two shores has been a genetic interface for 7,500 years, and a fraction of what naive NNLS models recover as "North African" in modern Spaniards is in fact this shared Neolithic substrate. The Taforalt-based model used in the Davidski Standard G25 avoids this confound by anchoring on a pre-Neolithic Moroccan reference, and the resulting percentages are correspondingly more conservative.

This modest demographic imprint in no way diminishes the depth of the cultural imprint. It simply reminds us, as in the case of the Anglo-Saxons in England, the Magyars in Hungary, or the Turks in Anatolia, that the identity of a people cannot be reduced to its language, its religion, or its genealogy. It is, almost always, more complex and more mixed than the founding narratives suggest. The Spanish identity is profoundly shaped by Latin grammar, Catholic Christianity, the Romance heritage of vulgar Latin, the Arabic loanwords from azulejo to almohada, the Berber agricultural techniques, the Jewish intellectual contributions of al-Andalus, and a thousand other inheritances that have nothing to do with autosomal DNA. Modern Spaniards are not "part Arab" or "part Berber" in their genes. The Basques are entirely indigenous. The Catalans are essentially indigenous. The Castilians, the Galicians, the Asturians, even the Andalusians, are overwhelmingly the descendants of the Hispano-Romans who lived on the peninsula in the 7th century, with a small but real North African layer concentrated in the south and southwest, plus an even smaller substrate of prehistoric Mediterranean exchange that predates al-Andalus by six thousand years.

Paleogenetics now allows us for the first time to measure each of these dimensions separately. The cultural and the genetic do not always travel together, and seeing the gap between them clearly is one of the most important things this discipline has taught us about human history.

References

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