It is corroborated by Mitochondrial DNA Affinities at the Atlantic Fringe of Europe: "Mitochondrial DNA analysis of Atlantic European samples has detected significant latitudinal clines for several clusters with Paleolithic (H) and Neolithic (J, U4, U5a1, and U5a1a) coalescence ages in Europe. These gradients may be explained as the result of Neolithic influence on a rather homogeneous Paleolithic background. There is also evidence that some Neolithic clusters reached this border by a continental route (J, J1, J1a, U5a1, and U5a1a), whereas others (J2) did so through the Mediterranean coast. An important gene flow from Africa was detected in the Atlantic Iberia. Specific sub-Saharan lineages appeared mainly restricted to southern Portugal, and could be attributed to historic Black slave trade in the area and to a probable Saharan Neolithic influence. In fact, U6 haplotypes of specific North African origin have only been detected in the Iberian peninsula northwards from central Portugal. Based on this peculiar distribution and the high diversity pi value (0.014 +/- 0.001) in this area compared to North Africa (0.006 +/- 0.001), we reject the proposal that only historic events such as the Moslem occupation are the main cause of this gene flow, and instead propose a pre-Neolithic origin for it."

To balance mitochondrial DNA analysis, we have examination of Y chromosome haplotypes in the region in The Genetic Legacy of Religious Diversity and Intolerance: Paternal Lineages of Christians, Jews, and Muslims in the Iberian Peninsula: "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."

Oh, by the way? This mestizaje is even more pronounced in the case of Mediterranean European-American populations, who underwent admixture with the indigenous populations of the Americas. Integrated urban peoples in the Americas are generally "mestizos" to some extent, but in places where there were fewer Indians, European admixture obviously dominated, with Indian admixture remaining a minority component, and the converse being true in regions where there were higher numbers of Indians.

The Indian populations of American countries correspond to their pre-contact prevalence, since the relative genetic homogeneity of Native Americans rendered them roughly similarly susceptible to foreign disease, with casualty rates ostensibly being approximately similar as a result. They sustained the highest population densities in the urban civilizations of Mesoamerica and the Andes, and central-southern Mexico, Central America, and Peru and Bolivia are therefore populated by the highest numbers and rates of Indians in the Western Hemisphere, whereas other countries had fewer Indians to begin with and ended up being populated by fewer in post-epidemic times. But that component is still there, as I said. Let's see how Argentina, your fabled white gem of South America, fares. Consider Corach's Evaluation of the Ethnic Composition in the Population of Argentina: "In the early XVI century, at the moment of the Spanish conquest, the territory of Argentina was inhabited by an Amerindian population with an extremely low population density. Accordingly it was supported by anthropologists that the Aboriginal component was in the past and is at present extremely scarce, considering that most inhabitants are of European ancestry and hence, Argentina and Uruguay claim to be the "European countries" of Latin America. In addition, it is accepted that the overall Amerindian population at the moment of the conquest was about 400,000 people. Nowadays, it is recognized by the government authorities that the Aboriginal component is less than 200,000 people, representing less than 0.5% of Argentina's population. Demographic estimations, census and counting may provide biased information. Some molecular analysis carried out on blood groups denoted quite different results compared with the anthropological data. In order to investigate the actual ethnic composition of our population uniparentally inherited genetic markers were chosen. Some Y-chromosome specific Single Nucleotide Polymorphisms (Snips) are considered ethnic-specific for Amerindian populations, such as the one located at the locus DYS199. Moreover, mitochondrial DNA sequencing of HVRI and the ins/del of 9bp in RV, might identify Haplogroups A, B, C, and D, that defines Amerindian matrilineage. Accordingly, the combined analysis of Y chromosome and mtDNA polymorphisms may provide a clue to address the ethnic composition of our heterogeneous population. A set of over 200 unrelated males inhabiting urban areas of some of the most populated provinces of Argentina including: Buenos Aires, Rio Negro, Mendoza, Santa Fe and Misiones were selected for analysis. All samples were typed for DYS199 and with the Charit's Y-STR nonaplex. Nucleotide sequence of mtDNA HVRI was obtained in all cases in order to identify Amerindian mitochondrial haplogroups. The proportion of individuals with either Y and mitochondrial haplogroups not considered Amerindian (Caucasian?) was 47%, those with both Y-chromosome and mtDNA Amerindian haplogroups were 10% and the mestizo condition (either one or the other amerindian lineages) accounted for 43%. As depicted in most Latin American countries, there is in Argentina, a clear asymmetry regarding Amerindian matrilineage mestizo (83.3%) when compared with Amerindian patrilineage (16.7%). A clear discrepancy arose in comparison with the physical anthropological position that claims a minimal aboriginal component in Argentina's population. This contribution provides additional information that supports a more relevant Amerindian component in a country that claimed to be the most European one of the entire Latin America."

Pre-Neolithic North African admixture + Moorish-Saracen occupation induced admixture + Amerindian admixture [in the American case] = Mestizo! Looks like some housecleaning is in order to purge the guineas!