Historical Population Movements Research Articles

Race in Circulation: Blood Banks and Forced Mobilities in the Eastern Mediterranean.

The emergence of blood transfusion services after the First World War provided new venues for nationalist and racial research. This paper focuses on racial serology in the Turkish Republic during the period between the 1920s and the 1970s, with particular attention to the role of the Greek-Turkish population exchange and the political conflict over Cyprus. These events entailed mass movements of refugees and violence based on communal identities, which were racialized through serological studies. As the blood of recently displaced people circulated through Greek and Turkish blood banks, physicians used data about blood types to substantiate historical hypotheses about past mobility. Through these genetic reconstructions of historical population movements, they took sides in contemporary territorial disputes. Beginning in the 1950s, the transnational conflict over Cyprus gradually transformed Turkish scientists' representation of Greek Orthodox communities' blood group frequencies, portraying them as "racially Turkish" rather than as biological others.

The Old and the New: Considerations in Arabic Historical Dialectology

Arabic historical dialectology has long been based on a historical methodology, one which seeks to link historical population movements with modern linguistic behavior. This article argues that a nexus of interrelated issues, centered around a general theme of “oldness,” has impaired this work, and proposes basic principles to avoid the misinterpretation of linguistic data. This article argues that there is a strong tendency to essentialize the idea of linguistic conservatism and attribute it to the groups that have archaic features. Against this view, it proposes that linguistic conservatism should be seen as a failure to participate in otherwise widespread innovations. It critiques the assumption that the modern dialect distribution is directly derived from the earliest settlements established during the Islamic conquests in the seventh century, arguing instead that long-term linguistic durability is unlikely. The article further challenges the assumption that highly conservative dialects such as those of Yemen are ancestral to modern dialects in a meaningful way, arguing instead that either more proximate ancestors or wave-like diffusion had a greater impact on the development of modern dialects. Finally, the paper suggests that a heuristic approach based on typical processes of language diffusion and human migration offers a more productive approach to understanding the history of Arabic dialects than a model based on historical events; many of the existing linguistic classifications may be directly derived from this heuristic.

Unraveling a fine-scale high genetic heterogeneity and recent continental connections of an Arabian Peninsula population

Recent studies have showed the diverse genetic architecture of the highly consanguineous populations inhabiting the Arabian Peninsula. Consanguinity coupled with heterogeneity is complex and makes it difficult to understand the bases of population-specific genetic diseases in the region. Therefore, comprehensive genetic characterization of the populations at the finest scale is warranted. Here, we revisit the genetic structure of the Kuwait population by analyzing genome-wide single nucleotide polymorphisms data from 583 Kuwaiti individuals sorted into three subgroups. We envisage a diverse demographic genetic history among the three subgroups based on drift and allelic sharing with modern and ancient individuals. Furthermore, our comprehensive haplotype-based analyses disclose a high genetic heterogeneity among the Kuwaiti populations. We infer the major sources of ancestry within the newly defined groups; one with an obvious predominance of sub-Saharan/Western Africa mostly comprising Kuwait-B individuals, and other with West Eurasia including Kuwait-P and Kuwait-S individuals. Overall, our results recapitulate the historical population movements and reaffirm the genetic imprints of the legacy of continental trading in the region. Such deciphering of fine-scale population structure and their regional genetic heterogeneity would provide clues to the uncharted areas of disease-gene discovery and related associations in populations inhabiting the Arabian Peninsula.

Complex interplay between neutral and adaptive evolution shaped differential genomic background and disease susceptibility along the Italian peninsula.

The Italian peninsula has long represented a natural hub for human migrations across the Mediterranean area, being involved in several prehistoric and historical population movements. Coupled with a patchy environmental landscape entailing different ecological/cultural selective pressures, this might have produced peculiar patterns of population structure and local adaptations responsible for heterogeneous genomic background of present-day Italians. To disentangle this complex scenario, genome-wide data from 780 Italian individuals were generated and set into the context of European/Mediterranean genomic diversity by comparison with genotypes from 50 populations. To maximize possibility of pinpointing functional genomic regions that have played adaptive roles during Italian natural history, our survey included also ~250,000 exomic markers and ~20,000 coding/regulatory variants with well-established clinical relevance. This enabled fine-grained dissection of Italian population structure through the identification of clusters of genetically homogeneous provinces and of genomic regions underlying their local adaptations. Description of such patterns disclosed crucial implications for understanding differential susceptibility to some inflammatory/autoimmune disorders, coronary artery disease and type 2 diabetes of diverse Italian subpopulations, suggesting the evolutionary causes that made some of them particularly exposed to the metabolic and immune challenges imposed by dietary and lifestyle shifts that involved western societies in the last centuries.

Population-genetic trees, maps, and narratives of the great human diasporas

From the 1960s, mathematical and computational tools have been developed to arrive at human population trees from various kinds of serological and molecular data. Focusing on the work of the Italian-born population geneticist Luigi Luca Cavalli-Sforza, I follow the practices of tree-building and mapping from the early blood-group studies to the current genetic admixture research. I argue that the visual language of the tree is paralleled in the narrative of the human diasporas, and I show how the tree was actually mapped onto the surface of the earth. This visual and textual structure is mirrored in the liberal discourse of unity in diversity that has been criticized as running counter to the socio-political effects of human population genetics. From this perspective, one may ask how far the phylogenetic diagram in its various forms is a manifestation of the physics of power that according to Michel Foucault consists in mechanisms that analyse distributions, movements, series, combinations, and that uses instruments to render visible, to register, to differentiate and to compare. It is one among other disciplinary technologies that ensure the ordering of human diversity. In the case of intra-human phylogenetic trees, population samples and labels are one issue. Another is that the separated branches seem to show groups of people, who have in reality been interacting and converging, as isolated. Often based on so-called isolated peoples, molecular tree diagrams freeze a hierarchical kinship system that is meant to represent a state before the great historical population movements.

Strong genetic admixture in the Altai at the Middle Bronze Age revealed by uniparental and ancestry informative markers.

The Altai Mountains have been a long-term boundary zone between the Eurasian Steppe populations and South and East Asian populations. To disentangle some of the historical population movements in this area, 14 ancient human specimens excavated in the westernmost part of the Mongolian Altai were studied. Thirteen of them were dated from the Middle to the End of the Bronze Age and one of them to the Eneolithic period. The environmental conditions encountered in this region led to the good preservation of DNA in the human remains. Therefore, a multi-markers approach was adopted for the genetic analysis of identity, ancestry and phenotype markers. Mitochondrial DNA analyses revealed that the ancient Altaians studied carried both Western (H, U, T) and Eastern (A, C, D) Eurasian lineages. In the same way, the patrilineal gene pool revealed the presence of different haplogroups (Q1a2a1-L54, R1a1a1b2-Z93 and C), probably marking different origins for the male paternal lineages. To go further in the search of the origin of these ancient specimens, phenotypical characters (i.e. hair and eye color) were determined. For this purpose, we adapted the HIrisPlex assay recently described to MALDI-TOF mass spectrometry. In addition, some ancestry informative markers were analyzed with this assay. The results revealed mixed phenotypes among this group confirming the probable admixed ancestry of the studied Altaian population at the Middle Bronze Age. The good results obtained from ancient DNA samples suggest that this approach might be relevant for forensic casework too.

Commentary on Sokal et al.'s "Historical Population Movements in Europe Influence Genetic Relationships in Modern Samples" (1996)

Commentary on Sokal et al.'s "Historical Population Movements in Europe Influence Genetic Relationships in Modern Samples" (1996) John H. Relethford Correction: Due to an error at the printer, the original article page range (605–606) was incorrect. The correct pagination is 607–608 and is reflected in this updated article. Click here for the corrected PDF. The genetic history of Europe has been the focus of many studies looking at the relative influence of geography, language, and prehistoric and historic population movements on genetic differences between populations. Two groups of researchers have had a major impact on the evolution of these studies—Luca Cavalli-Sforza and colleagues (e.g., Cavalli-Sforza et al. 1994; Menozzi et al. 1978) and Robert Sokal and colleagues. The paper reprinted here is one of many of Sokal's innovative approaches to population genetics, adroitly integrating anthropological data and hypotheses and genetic data in a rigorous and statistically precise manner. The focus of the paper is the use of ethnohistorical data to test the hypotheses of the influence of historical population movements over the past 4,000 years on the genetic structure of contemporary human populations across Europe. Sokal et al. used ethnohistorical data to construct a distance measure based on the likely relative ancestral contribution of different ethnic groups, which were defined in terms of language family membership. They found a significant correlation with genetic distance that was derived from a large sample of classical genetic markers. Further, they showed that this correlation remained even after controlling for geographic distance, thus showing that the expected relationship was not a byproduct of spatial autocorrelation. In addition, they found that the strength of the correlations increased over time, particularly during the past 400 years. This paper is an excellent example of the multidisciplinary approaches that Bob Sokal brought to investigations of genetic history. Ethnohistory is a key factor in the studies of anthropological genetics, because the origin of different groups and their contact with other populations, both near and far, affect genetic variation. Most often, the history of different populations is used to make indirect inferences regarding observed patterns of genetic similarity. For example, in my study of 19th-century Irish anthropometrics, the observed distinction of two island populations was explained by noting that their history pointed to a large influx of English soldiers (Relethford 1988). For many studies, historical hypotheses are treated in such an indirect fashion. What makes Sokal's paper so innovative is that he and his colleagues quantified European ethnohistory through the compilation of a massive database on European-population movements (this [End Page 607] database is still available at the Web page cited in the paper). The database alone is a remarkable achievement that represents the enormous potential in translating anthropological hypotheses into testable statistical hypotheses. Whereas the complexity of quantifying historic population movements from ethnohistorical data might appear daunting to many (myself included), Sokal and colleagues presented their approach clearly and logically, answering potential criticisms and noting both strengths and weaknesses of their approach. It has been over 16 years since this paper was published, but its results and methodology still hold up. The most dramatic change over the intervening years has been the increasing use of DNA markers, providing both new analytic approaches and an enormous number of loci. For example, Novembre et al.'s (2008) analysis of genetic variation in Europeans used more than half a million SNPs, orders of magnitude above the 26 genetic systems used in Sokal's paper. Developments in genetic technology have also allowed the increasing use of ancient DNA analysis to help probe questions of prehistoric movements into Europe (e.g., Haak et al. 2010; Skoglund et al. 2012). It is likely that such developments will continue as the new age of genomic analysis continues to unfold. I think that these newer studies will supplement, though not replace, the earlier studies of European genetic history. The methods outlined by Sokal and colleagues and their massive achievement in quantifying their ethnohistorical database should continue to guide future analysis. At present, DNA markers still do not cover the number of populations or degree of geographic sampling that have been obtained from previous decades of...

Commentary on Sokal et al.'s “Historical Population Movements in Europe Influence Genetic Relationships in Modern Samples” (1996)

The genetic history of Europe has been the focus of many studies looking at the relative influence of geography, language, and prehistoric and historic population movements on genetic differences between populations. Two groups of researchers have had a major impact on the evolution of these studies—Luca Cavalli-Sforza and colleagues (e.g., Cavalli-Sforza et al. 1994; Menozzi et al. 1978) and Robert Sokal and colleagues. The paper reprinted here is one of many of Sokal’s innovative approaches to population genetics, adroitly integrating anthropological data and hypotheses and genetic data in a rigorous and statistically precise manner. The focus of the paper is the use of ethnohistorical data to test the hypotheses of the influence of historical population movements over the past 4,000 years on the genetic structure of contemporary human populations across Europe. Sokal et al. used ethnohistorical data to construct a distance measure based on the likely relative ancestral contribution of different ethnic groups, which were defined in terms of language family membership. They found a significant correlation with genetic distance that was derived from a large sample of classical genetic markers. Further, they showed that this correlation remained even after controlling for geographic distance, thus showing that the expected relationship was not a byproduct of spatial autocorrelation. In addition, they found that the strength of the correlations increased over time, particularly during the past 400 years. This paper is an excellent example of the multidisciplinary approaches that Bob Sokal brought to investigations of genetic history. Ethnohistory is a key factor in the studies of anthropological genetics, because the origin of different groups and their contact with other populations, both near and far, affect genetic variation. Most often, the history of different populations is used to make indirect inferences regarding observed patterns of genetic similarity. For example, in my study of 19th-century Irish anthropometrics, the observed distinction of two island populations was explained by noting that their history pointed to a large influx of English soldiers (Relethford 1988). For many studies, historical hypotheses are treated in such an indirect fashion. What makes Sokal’s paper so innovative is that he and his colleagues quantified European ethnohistory through the compilation of a massive database on European-population movements (this

Historical Population Movements in Europe Influence Genetic Relationships in Modern Samples

We have newly constructed an ethnohistorical database consisting of 3460 records of ethnic locations and movements in Europe since 2200 B.C. Using this database, we computed vectors of proportions that peoples speaking various language families contributed to the gene pools of 2216 1° × 1° land-based quadrats of Europe. From these vectors we computed ethnohistorical distances as arc distances between all pairs of quadrats. We used these distances as predictors of genetic distances, which we calculated independently from 26 genetic systems. We find significant partial correlations between ethnohistorical and genetic distances when geographic distance, a common causative factor, is held constant. Ethnohistorical distances explain a significant amount of the genetic variation observed in modern populations. These results are highly robust to simulated errors in and omissions from the ethnohistorical database. Randomization tests show that the historical sequence of the movements does not affect estimates of the ethnohistory-genetics correlation, but the geographic locations of movements do. We track the development of the ethnohistory-genetics correlation through time and show it to be gradual and cumulative over the past 4200 years.

Historical Population Movements in Europe Influence Genetic Relationships in Modern Samples

We have newly constructed an ethnohistorical database consisting of 3460 records of ethnic locations and movements in Europe since 2200 B.C. Using this database, we computed vectors of proportions that peoples speaking various language families contributed to the gene pools of 2216 1 degree x 1 degree land-based quadrats of Europe. From these vectors we computed ethnohistorical distances as arc distances between all pairs of quadrats. We used these distances as predictors of genetic distances, which we calculated independently from 26 genetic systems. We find significant partial correlations between ethnohistorical and genetic distances when geographic distance, a common causative factor, is held constant. Ethnohistorical distances explain a significant amount of the genetic variation observed in modern populations. These results are highly robust to simulated errors in and omissions from the ethnohistorical database. Randomization tests show that the historical sequence of the movements does not affect estimates of the ethnohistory-genetics correlation, but the geographic locations of movements do. We track the development of the ethnohistory-genetics correlation through time and show it to be gradual and cumulative over the past 4200 years.

Autosomal genetic diversity in non‐breed horses from eastern Eurasia provides insights into historical population movements

Many events in the history of eastern Eurasia, including the process of domestication itself, the initial spread of domestic horses and subsequent movements, are believed to have affected the genetic structure of domestic horse populations in this area. We investigated levels of within- and between-population genetic diversity in 'non-breed horses' (working horses sampled in remote areas) from 17 locations in Asia and parts of Eastern Europe, using 26 autosomal microsatellite loci. Non-breed horses have not been subject to the same intensity of artificial selection and closed breeding as have most breed animals and are thus expected to better reflect the population history of domestic horses. Despite geographic distances of between 300 and 7000 km between sampling locations, pairwise F (ST) was very low (range: <0.001 to -0.033), suggesting historically high levels of gene flow. Our analyses of non-breed horses revealed a pattern of isolation by distance and a significant decline in genetic diversity (expected heterozygosity and allelic richness) from east to west, consistent with a westward expansion of horses out of East Asia. Although the timing of this putative expansion is unclear, our results highlight the benefit of studying animals that do not belong to particular breeds when investigating aspects of a population's history.

A Geographic Cline of Skull and Brain Morphology among Individuals of European Ancestry

Background: Human skull and brain morphology are strongly influenced by genetic factors, and skull size and shape vary worldwide. However, the relationship between specific brain morphology and genetically-determined ancestry is largely unknown. Methods: We used two independent data sets to characterize variation in skull and brain morphology among individuals of European ancestry. The first data set is a historical sample of 1,170 male skulls with 37 shape measurements drawn from 27 European populations. The second data set includes 626 North American individuals of European ancestry participating in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) with magnetic resonance imaging, height and weight, neurological diagnosis, and genome-wide single nucleotide polymorphism (SNP) data. Results: We found that both skull and brain morphological variation exhibit a population-genetic fingerprint among individuals of European ancestry. This fingerprint shows a Northwest to Southeast gradient, is independent of body size, and involves frontotemporal cortical regions. Conclusion: Our findings are consistent with prior evidence for gene flow in Europe due to historical population movements and indicate that genetic background should be considered in studies seeking to identify genes involved in human cortical development and neuropsychiatric disease.

Review Synthetic Report: Genomic architecture of deafness in Turkey reflects its rich past

More than 60% of prelingual deafness is genetic in origin, and of these up to 93% are monogenic autosomal recessive traits. Turkey has been continually inhabited since ancient times with traditional settlement of small and isolated villages. There is a high level of both parental consanguinity and assortative mating among the deaf and a long history of the use of sign language. All of these factors are known to have a profound influence on the survival, expression and spread of new mutations for deafness. Many of the identified deafness alleles are private in a single family or in an isolated village that reflect the effect of small population size or parental consanguinity. Single origins have been demonstrated for some mutations, including 35delG in GJB2 and R84W in TMIE, that are recurrently identified in unrelated families. Historic population movements in and around Turkey leading to gene flow and consequently founder effects are responsible for these mutations. Assortative mating among the deaf is likely to have contributed to contemporary high frequency of certain deafness loci. Key words: Deafness, assortative mating, parental consanguinity, founder effect, Turkey, hearing loss.

Genetic variation in South Indian castes: evidence from Y-chromosome, mitochondrial, and autosomal polymorphisms

BackgroundMajor population movements, social structure, and caste endogamy have influenced the genetic structure of Indian populations. An understanding of these influences is increasingly important as gene mapping and case-control studies are initiated in South Indian populations.ResultsWe report new data on 155 individuals from four Tamil caste populations of South India and perform comparative analyses with caste populations from the neighboring state of Andhra Pradesh. Genetic differentiation among Tamil castes is low (RST = 0.96% for 45 autosomal short tandem repeat (STR) markers), reflecting a largely common origin. Nonetheless, caste- and continent-specific patterns are evident. For 32 lineage-defining Y-chromosome SNPs, Tamil castes show higher affinity to Europeans than to eastern Asians, and genetic distance estimates to the Europeans are ordered by caste rank. For 32 lineage-defining mitochondrial SNPs and hypervariable sequence (HVS) 1, Tamil castes have higher affinity to eastern Asians than to Europeans. For 45 autosomal STRs, upper and middle rank castes show higher affinity to Europeans than do lower rank castes from either Tamil Nadu or Andhra Pradesh. Local between-caste variation (Tamil Nadu RST = 0.96%, Andhra Pradesh RST = 0.77%) exceeds the estimate of variation between these geographically separated groups (RST = 0.12%). Low, but statistically significant, correlations between caste rank distance and genetic distance are demonstrated for Tamil castes using Y-chromosome, mtDNA, and autosomal data.ConclusionGenetic data from Y-chromosome, mtDNA, and autosomal STRs are in accord with historical accounts of northwest to southeast population movements in India. The influence of ancient and historical population movements and caste social structure can be detected and replicated in South Indian caste populations from two different geographic regions.

Measuring European Population Stratification with Microarray Genotype Data

A proper understanding of population genetic stratification--differences in individual ancestry within a population--is crucial in attempts to find genes for complex traits through association mapping. We report on genomewide typing of approximately 10,000 single-nucleotide polymorphisms in 297 individuals, to explore population structure in Europeans of known and unknown ancestry. The results reveal the presence of several significant axes of stratification, most prominently in a northern-southeastern trend, but also along an east-west axis. We also demonstrate the selection and application of EuroAIMs (European ancestry informative markers) for ancestry estimation and correction. The Coriell Caucasian and CEPH (Centre d'Etude du Polymorphisme Humain) Utah sample panels, often used as proxies for European populations, are found to reflect different subsets of the continent's ancestry.

The patterns of historical population movements in Europe and some of their genetic consequences.

Population movements of 891 ethnic units in Europe over the past 4,200 years, and the correlations of these movements with modern genetic distances were investigated on a one-degree-square grid of the continent. There is significant spatial pattern in movements from sources, to targets, and overall. Patterns change significantly over time. Patterns of sources and targets differ significantly. Modern movements are more numerous than ancient movements. Movements on the periphery of Europe are few in number and are concentrated in direction, while Central European movements are numerous and unconcentrated in direction. Modern genetic distance is negatively correlated with the amount of population exchange between localities. Regional genetic variance is positively correlated with number of movements into, but not out of, areas. The findings are interpreted in the context of European ethnohistory and population biology. Am. J. Hum. Biol. 9:391-404, 1997. © 1997 Wiley-Liss, Inc.

Alloalbuminemia and the migrations of native Americans

Genetic variants of serum albumin are known from populations around the world. Most are quite rare and limited to one family or population, but among several North and Central American Indian populations, two variants, albumins Naskapi and Mexico, reach polymorphic frequencies. No selective advantage to either of these variants has yet been discovered. Their distribution may reflect, in part, prehistoric and historic population movements, and intertribal contacts such as these can now be reconstructed from archeological, linguistic, and historical investigations. In addition, albumin Naskapi has been discovered in at least one non-Indian population, the “Eti” Turks, and perhaps among Indians of the Punjab in north India. If albumin Naskapi has not arisen by independent mutations in each population, its presence in Asia is consistent with an Asian origin of American Indians, and further study could provide more specific localization. Additional analyses of other genetic polymorphisms in these populations may provide additional information on the affinities and origins of the early migrants to the New World.

G//ana territorial organization

This analysis of G//ana territorial organization shows how land rights are acquired and how they affect patterns of land use. Both spatial and social boundaries are discussed. It is shown that the appearance of overlapping spatial boundaries is clarified through a focus on the land rights of individuals and a consideration of historical population movements over the region. The discussion of social boundaries shows that, while interterritorial marriage and mobility networks are extensive, increases in property and food production appear to be associated with a closing of social boundaries (increased social nucleation). This is suggested by greater endogamy and a trend toward patrilineal inheritance of land rights in recent years.