Martin Hájek

A bidirectional corridor in the Sahel-Sudan belt and the distinctive features of the Chad Basin populations: a history revealed by the mitochondrial DNA genome.

The Chad Basin was sparsely inhabited during the Stone Age, and its continual settlement began with the Holocene. The role played by Lake Chad in the history and migration patterns of Africa is still unclear. We studied the mitochondrial DNA (mtDNA) variability in 448 individuals from 12 ethnically and/or economically (agricultural/pastoral) different populations from Cameroon, Chad, Niger and Nigeria. The data indicate the importance of this region as a corridor connecting East and West Africa; however, this bidirectional flow of people in the Sahel‐Sudan Belt did not erase features peculiar to the original Chad Basin populations. A new sub‐clade, L3f2, is described, which together with L3e5 is most probably autochthonous in the Chad Basin. The phylogeography of these two sub‐haplogroups seems to indicate prehistoric expansion events in the Chad Basin around 28,950 and 11,400 Y.B.P., respectively. The distribution of L3f2 is virtually restricted to the Chad Basin alone, and in particular to Chadic speaking populations, while L3e5 shows evidence for diffusion into North Africa at about 7,100 Y.B.P. The absence of L3f2 and L3e5 in African‐Americans, and the limited number of L‐haplotypes shared between the Chad Basin populations and African‐Americans, indicate the low contribution of the Chad region to the Atlantic slave trade.

Regional Differences in the Distribution of the Sub-Saharan, West Eurasian, and South Asian mtDNA Lineages in Yemen

Despite its key location for population movements out of and back into Africa, Yemen has not yet been sampled on a regional level for an investigation of sub-Saharan, West Eurasian, and South Asian genetic contributions. In this study, we present mitochondrial DNA (mtDNA) data for regionally distinct Yemeni populations that reveal different distributions of mtDNA lineages. An extensive database of mtDNA sequences from North and East African, Middle Eastern and Indian populations was analyzed to provide a context for the regional Yemeni mtDNA datasets. The groups of western Yemen appear to be most closely related to Middle Eastern and North African populations, while the eastern Yemeni population from Hadramawt is most closely related to East Africa. Furthermore, haplotype matches with Africa are almost exclusively confined to West Eurasian R0a haplogroup in southwestern Yemen, although more sub-Saharan L-type matches appear in more northern Yemeni populations. In fact, Yemeni populations have the highest frequency of R0a haplotypes detected to date, thus Yemen or southern Arabia may be the site of the initial expansion of this haplogroup. Whereas two variants of the sub-Saharan haplogroup M1 were detected only in southwestern Yemen close to the Bab el-Mandeb Strait, different non-African M haplotypes were detected at low frequencies (approximately 2%) in western parts of the country and at a higher frequency (7.5%) in the Hadramawt. We conclude that the Yemeni gene pool is highly stratified both regionally and temporally and that it has received West Eurasian, Northeast African, and South Asian gene flow.

mtDNA of Fulani Nomads and Their Genetic Relationships to Neighboring Sedentary Populations

ABSTRACT Despite the large size of the contemporary nomadic Fulani population (roughly 13 million people), the genetic diversity and degree of differentiation of Fulanis compared to other sub-Saharan populations remain unknown. We sampled four Fulani nomad populations (n =186) in three countries of sub-Saharan Africa (Chad, Cameroon, and Burkina Faso) and analyzed sequences of the first hypervariable segment of the mitochondrial DNA. Most of the haplotypes belong to haplogroups of West African origin, such as L1b, L3b, L3d, L2b, L2c, and L2d (79.6% in total), which are all well represented in each of the four geographically separated samples. The haplogroups of Western Eurasian origin, such as J1b, U5, H, and V, were also detected but in rather low frequencies (8.1% in total). As in African hunter-gatherers (Pygmies and Khoisan) and some populations from central Tunisia (Kesra and Zriba), three of the Fulani nomad samples do not reveal significant negative values of Fus selective neutrality test. The multidimensional scaling of FST genetic distances of related sub-Saharan populations and the analysis of molecular variance (AMOVA) show clear and close relationships between all pairs of the four Fulani nomad samples, irrespective of their geographic origin. The only group of nomadic Fulani that manifests some similarities with geographically related agricultural populations (from Guinea-Bissau and Nigeria) comes from Tcheboua in northern Cameroon.

Linking the sub-Saharan and West Eurasian gene pools: maternal and paternal heritage of the Tuareg nomads from the African Sahel

The Tuareg presently live in the Sahara and the Sahel. Their ancestors are commonly believed to be the Garamantes of the Libyan Fezzan, ever since it was suggested by authors of antiquity. Biological evidence, based on classical genetic markers, however, indicates kinship with the Beja of Eastern Sudan. Our study of mitochondrial DNA (mtDNA) sequences and Y chromosome SNPs of three different southern Tuareg groups from Mali, Burkina Faso and the Republic of Niger reveals a West Eurasian-North African composition of their gene pool. The data show that certain genetic lineages could not have been introduced into this population earlier than ∼9000 years ago whereas local expansions establish a minimal date at around 3000 years ago. Some of the mtDNA haplogroups observed in the Tuareg population were involved in the post-Last Glacial Maximum human expansion from Iberian refugia towards both Europe and North Africa. Interestingly, no Near Eastern mtDNA lineages connected with the Neolithic expansion have been observed in our population sample. On the other hand, the Y chromosome SNPs data show that the paternal lineages can very probably be traced to the Near Eastern Neolithic demic expansion towards North Africa, a period that is otherwise concordant with the above-mentioned mtDNA expansion. The time frame for the migration of the Tuareg towards the African Sahel belt overlaps that of early Holocene climatic changes across the Sahara (from the optimal greening ∼10 000 YBP to the extant aridity beginning at ∼6000 YBP) and the migrations of other African nomadic peoples in the area.

Out of Arabia – the settlement of island Soqotra as revealed by mitochondrial and Y chromosome genetic diversity

The Soqotra archipelago is one of the most isolated landmasses in the world, situated at the mouth of the Gulf of Aden between the Horn of Africa and southern Arabia. The main island of Soqotra lies not far from the proposed southern migration route of anatomically modern humans out of Africa approximately 60,000 years ago (kya), suggesting the island may harbor traces of that first dispersal. Nothing is known about the timing and origin of the first Soqotri settlers. The oldest historical visitors to the island in the 15th century reported only the presence of an ancient population. We collected samples throughout the island and analyzed mitochondrial DNA and Y-chromosomal variation. We found little African influence among the indigenous people of the island. Although the island population likely experienced founder effects, links to the Arabian Peninsula or southwestern Asia can still be found. In comparison with datasets from neighboring regions, the Soqotri population shows evidence of long-term isolation and autochthonous evolution of several mitochondrial haplogroups. Specifically, we identified two high-frequency founder lineages that have not been detected in any other populations and classified them as a new R0a1a1 subclade. Recent expansion of the novel lineages is consistent with a Holocene settlement of the island approximately 6 kya.

mtDNA sequences of Chadic-speaking populations from northern Cameroon suggest their affinities with eastern Africa

Background: No mitochondrial DNA (mtDNA) sequences from Chadic-speaking peoples have yet been reported, even though these populations inhabit a vast territory from eastern Nigeria to central Chad. This paper deals with the mtDNA sequences of four Central Chadic populations (Hide, Kotoko, Mafa and Masa) from northern Cameroon, biological samples from which were collected during anthropological research in the area of their homeland. Objective: The main goals of this article are to report new mtDNA sequences of Chadic-speaking populations, to analyse their genetic diversity and to establish their relationships within the peri-Saharan area in respect of geography and languages. Subject and methods: The analyses are based on 104 mtDNA haplotypes, which can be localized into four different areas of northern Cameroon. Data collection was based on a strict geographical sampling strategy; the ethnonyms are retained here only for comparative purposes. Results: None of the examined Chadic populations displays a departure from the normal mismatch distribution pattern, and the null hypothesis of the expansion event cannot be rejected. Analyses of molecular variance and FST genetic distances revealed that the Chadic-speaking groups of northern Cameroon share more similarities with the populations of the Upper and Middle Nile Valley and East Africa than with populations from Central Africa. The results show geographical clustering to be more important than the correlation of linguistic affiliations with molecular genetic data. Conclusion: The observation that the Chadic group reveals some affinities to East Africans is extremely surprising giving the present-day geographical distance (around 2000 km) between them. These observations complement recent linguistic and archaeological findings, which consider the Chadic branch in the Afro-Asiatic phylum to be of eastern origin. A continuous, well-defined, geographic sampling strategy of the different genetic polymorphisms of the native populations of sub-Saharan Africa is further needed as the only way of understanding the differentiation of the mtDNA sequences at a micro-regional scale.

‘Watch out for politics’: exit, voice and other strategies of discontent in late Czech socialism

The manner in which mass loyalty in socialist and other post-totalitarian societies is maintained is still a matter of discussion. To contribute to the debate this article studies strategies of discontent in late Czech socialism as described in 60 oral history narratives of three groups of narrators (communist functionaries, dissidents and ordinary people). Drawing on a modified version of Hirsch’s exit–voice–loyalty model, the study reveals an important characteristic of the expression of discontent in this post-totalitarian society – the strategic distinction between political and non-political behaviour. Labelling discontent as either a political or non-political matter was a key trait of power plays.

Dual Discursive Patterns in Czech Activists’ Internet Media Communication

This article studies the internet media communication of 12 organizations representing Czech trade union, feminist, human rights and environmental movements. Drawing on Foucault’s concept that discourse has a formative influence resulting in a specific system of statement allocation, the study investigates the discursive characteristics of activists’ communication. The research is methodologically based on a quantitative exploration of co-occurrences of frequent lexical items. The computer-assisted text analysis reveals an important characteristic of the communication — an internal split in two discursive areas: on the one hand, the ‘conditions area’, dedicated to phrasing the existential conditions of subjects of contest or protection, and, on the other hand, the ‘contention area’, referring to strategies and negotiation with movement opponents. In the study’s interpretation, the discourse constrains activist organizations to communicate both about the life conditions of actors/subjects and about their claims and negotiations, but in large measure separately.

Mitochondrial DNA and craniofacial covariability of Chad Basin females indicate past population events

The Chad Basin lies in the middle of the Sudanic African belt between the Sahara and the tropical rain forests. Its present‐day settlement is a result of Holocene climatic changes and human immigrations from different parts of Africa. This study presents a statistical analysis of the relationships of physical features (stature and five main craniofacial measurements) and mitochondrial (mtDNA) haplogroup classifications in a sample of 282 adult individuals belonging to seven populations of different ethno‐linguistic groups living in the Chad Basin. Drawing on the analysis of variance, we identified a female‐specific DNA association between mtDNA haplogroup assignment and facial height. More specifically, the mtDNA haplogroups of East‐African origin occur more frequently in females with relatively longer faces and, conversely, the mtDNA of West‐African origin are found more frequently in females with lower faces. Interestingly, this kind of association is not found in the males of the same populations. Our interpretation refers mainly to population history; we suggest that facial height and mtDNA haplogroup co‐variance in Chad Basin females reflects a long‐term east–west population distribution in the past that made the facial differentiation possible. Am. J. Hum. Biol., 2008.

Reasoning behind choices: rationality and social norms in the housing market behaviour of first-time buyers in the Czech Republic

Abstract The main objective of this paper is to draw attention to the influence of social norms on housing market behaviour. The research is based on an in-depth qualitative study of first-time buyers in the Czech Republic. We found systemic deviations from economically rational behaviour (as defined by mainstream housing economic theory) that stem from the influence of a dominant housing social norm about what constitutes the ‘right’ housing tenure. We show how the influence of a social norm constrains financial, pragmatic, utility- or investment-based considerations of Czech home-buyers. Sociology can thus significantly contribute to recent econometric research about sources of housing market instability.