El mapa fue creado y presentado en agosto de 2008 en el diario Público, que tampoco daba demasiada información sobre su fuente. Finalmente, en base a lo poco que se especificaba, localicé el estudio en que se basaba el mapa: se trata de "The Genetic Legacy of Religious Diversity and Intolerance: Paternal Lineages of Christians, Jews, and Muslims in the Iberian Peninsula", elaborado por Susan M. Adams, Elena Bosch, Patricia L. Balaresque, Stéphane J. Ballereau, Andrew C. Lee, Eduardo Arroyo, Ana M. López-Parra, Mercedes Aler, Marina S. Gisbert Grifo, Maria Brion, Angel Carracedo, João Lavinha, Begoña Martínez-Jarreta, Lluis Quintana-Murci, Antònia Picornell, Misericordia Ramon, Karl Skorecki, Doron M. Behar, Francesc Calafell y Mark A. Jobling. La lista completa de los investigadores participantes muestra la participación de universidades de Inglaterra, Francia, Portugal e Israel, pero fundamentalmente de universidades españolas (La Complutense de Madrid, la Universidad de Valencia, la de Santiago de Compostela, la de Zaragoza, la de las Islas Baleares, y la Pompeu Fabra, de Barcelona), lo que resulta especialmente curioso: investigadores nacionales deberían poder advertir que algo anda mal en tal caso: o falla la muestra, o fallan las hipótesis, o fallan los instrumentos, pero el corte es a evidentemente simplista y fallido. Del abstract del artículo se puede deducir la anticipación de conclusiones al desarrollo de la investigación:
Most studies of European genetic diversity have focused on large-scale variation and interpretations based on events in prehistory, but migrations and invasions in historical times could also have had profound effects on the genetic landscape. The Iberian Peninsula provides a suitable region for examination of the demographic impact of such recent events, because its complex recent history has involved the long-term residence of two very different populations with distinct geographical origins and their own particular cultural and religious characteristics—North African Muslims and Sephardic Jews. To address this issue, we analyzed Y chromosome haplotypes, which provide the necessary phylogeographic resolution, in 1140 males from the Iberian Peninsula and Balearic Islands. Admixture analysis based on binary and Y-STR haplotypes indicates a high mean proportion of ancestry from North African (10.6%) and Sephardic Jewish (19.8%) sources. Despite alternative possible sources for lineages ascribed a Sephardic Jewish origin, these proportions attest to a high level of religious conversion (whether voluntary or enforced), driven by historical episodes of social and religious intolerance, that ultimately led to the integration of descendants. In agreement with the historical record, analysis of haplotype sharing and diversity within specific haplogroups suggests that the Sephardic Jewish component is the more ancient. The geographical distribution of North African ancestry in the peninsula does not reflect the initial colonization and subsequent withdrawal and is likely to result from later enforced population movement—more marked in some regions than in others—plus the effects of genetic drift.Es decir, de por sí el propio resúmen del estudio reconoce que hay algo incongruente en el componente sefardí y en el norteafricano, y muestra una afirmación relacionada con la conversión forzada que lo tiñe de unilateralidad. Dos acotaciones en el propio artículo también relativizan el porcentaje sefardí, pero sin abandonar las conclusiones postuladas:
(...) whereas Basque and Moroccan samples are drawn from sizeable populations that have maintained their existence in situ, with a probable low level of admixture with the other parentals, the Sephardic Jewish sample is taken from a comparatively small group of self-defined individuals whose ancestors have lived in various parts of the Iberian Peninsula and were themselves probably subject to some degree of admixture with Iberians. This potential past admixture would have the effect of increasing the perceived level of Sephardic Jewish ancestry compared to the actual proportion.
(...) An additional factor that could lead to overestimation of Sephardic Jewish ancestry proportions is the effect of other influences on the Iberian Peninsula from eastern Mediterranean populations that might have imported lineages such as G, K∗, and J. These influences fall into two different time periods: the Neolithic era, beginning in 10 KYA, the demographic effects of which are a matter for heated debate; and the last three millennia, the time period of Greek and Phoenician colonization. Effects in the second case are expected to be most marked in the eastern part of our sample area, but despite this, the apparent Sephardic Jewish ancestry proportions remain substantial in the west (...). The confounding effects of earlier population movement are likely to be particularly strong for Ibiza, Majorca, and Minorca, whose island natures make them more susceptible to influence by immigration and subsequent drift than inland sites. For example, history records that Ibiza, found to have a high apparent Sephardic Jewish ancestry proportion in our study, had an insignificant Jewish population compared to its neighbors yet had previously been an important Phoenician colony. Likewise, Minorca is recorded as having a substantial Jewish population, yet here, it shows no Sephardic Jewish ancestry.Es decir,este componente está probablemente sobreestimado o contaminado, quizá identificando un orígen global mediooriental (probablemente fenicio, o aún árabe) como judío.
Buscando referencias al artículo, encontré varias críticas fundamentadas, algunas de ellas próximas a estas observaciones hechas ya en el propio documento.
Dos son particularmente interesantes: la escrita por Dienekes Pontikós, seguida por múltiples observaciones críticas de otros comentaristas, y la publicada por ENotes.
Resume sus observaciones Dienekes:
This article will be an invaluable resource for students of Iberian Y-chromosome diversity, due to the numerous 18-marker haplotypes from all regions contained in the supplement.En particular, sobre la composición de los dos tercios "iberos", y la selección contaminada de hipótesis:
The authors modeled the Iberian population as a 3-way mix with "Basque", "Sephardic", and "North African". The main thesis is that the fairly substantial "Sephardic" and "North African" components identified are evidence of substantial religious conversion of Jews and Muslims.
The North African component may be roughly correct; it is similar to the 6% reported for Sicily, which was also occupied by Muslims. The Sephardic component is however suspect, as it may be of either Arabic or Italian origin, or indeed even earlier population movements from the Eastern Mediterranean.
Another point of contention is with the use of Basques as pre-Sephardic/Muslim Iberians. The Christian population of Iberia prior to the arrival of the Jews and Muslims, included non-Basque Celtiberians, Romance speakers, as well as a Visigoth/Germanic layer.
Nor is it clear that the North African component in Iberians stems from Muslim converts, since bidirectional movement of populations across Gibraltar may predate the occupation of Iberia.
(...) From the paper:Sobre la presencia ignorada en el estudio de otros componentes:
To formally assess the impact of North African and Sephardic Jewish contributions on the indigenous population, we carried out admixture analysis, employing the mY estimator and treating the study populations as hybrids of three parental populations. We chose the Basques as the Iberian parental sample. This is justified on the basis of a relative absence of Muslim occupation of the Basque region and supported by the genetic distinctiveness of the Basque and neighboring Gascon samples (Figure 3).In plain English, the authors could just as well have written: "Basques are distinct from other Iberians. This may be due to either (i) the fact that there were indeed differences between Basques and other Iberians even before the Muslim occupation/Jewish settlement: after all they occupy their own region, not Iberia-at-large, and speak a different language. Or, (ii) it could be that the rest of the Iberians have undergone substantial admixture with Muslims and Jews. We arbitrarily choose hypothesis (ii) as our premise, and ¡qué sorpresa! our data backs up our pre-supposed idea."
(...) It is true that Greek or Phoenician influence would be concentrated in particular regions. Whether Y-chromosomes "stay put" for a period of 2.5 thousand years is a different question. But, Neolithic Y-chromosomes certainly would have had ample time to be fairly uniformly distributed across the peninsula. And, the most important single aspect of Iberian history, i.e., the Roman conquest, which would have introduced not only the dominant language, but also a fair amount of genes is totally ignored.El otro conjunto de observaciones (ENotes) refiere lo que se ha comentado aquí: que incluso los investigadores matizaron sus conclusiones:
In fact this is the single reference to the Roman period in this paper:
The Jewish presence was very long-established, with some evidence that it predated the Christian era; many Jews, however, are thought to have arrived during the Roman periodBut, seriously, in the Roman period, not only Jews, but most importantly Romans settled in Iberia. And, by the way, they must have been numerous enough to change the language. But, let's ignore these pesky Romans and pretend that Iberians are a simple mix of Basques/Moroccan/Jews.
En el artículo no firmado "Spanish People, al resumir los estudios genéticos sobre la península, se dice:
According to a widely publicited recent study (December 2008) published in the American Journal of Human Genetics, 19.8 percent of modern Spaniards (and Portuguese) have DNA reflecting Sephardic Jewish ancestry (compared to 10.6 percent having DNA reflecting Moorish ancestors with wide geographical variation, ranging from 2.5% in Catalonia to 21.7% in Northwest Castile). The Sephardic result is contradicted or not replicated in the body of genetic studies done in Iberia and has been subsequently questioned by the authors and by Stephen Oppenheimer since earlier migrations from the Eastern Mediterranean, ranging from the Phoenicians to the Neolithic may also account for the estimates offered for Sephardic ancestry: "They are really assuming that they are looking at his migration of Jewish immigrants, but the same lineages could have been introduced in the Neolithic". On the other hand, Chris Tyler-Smith, a collaborator with the team that carried the study, argues that the individual differences in Y-chromosome markers suggest that Iberians and Sephardic Jews must share ancestry more recent than several millennia, even though in also a recent study (October 2008) they attributed those same lineages in Iberia and the Balearic Islands as of Phoenician origin.Más allá de la validez de este estudio,existen aquí múltiples líneas de análisis: cuál es la evolución de la composición de la población de la península, cómo impactaron en la construcción de los perfiles regionales, las diferencias lingüísticas y culturales.
Una observación que surge de los datos: si hacemos un corte partiendo de la historia escrita y transmitida, existe un sustrato de población dominada por el imperio romano, que debe haber subsistido y mezclado con la población minoritaria romana, que ambos componentes (mas los fenicios, griegos, sefardíes y otros que pudieran haber coexistido perviamente en las costas, o que fueran introducidos por el imperio) pasaron a ser dominados y administrados por el componente visigodo muy minoritario, y que este nuevo conjunto pasó a ser dominado y administrado por el nuevo componente musulman (arabe + bereber), y así, hasta llegar a la reconquista. Mucho para recorrer...
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