David Zeitlyn

Gift economies in the development of open source software: anthropological reflections

Abstract Building on Eric Raymond’s work this article discusses the motivation and rewards that lead some software engineers to participate in the open source movement. It is suggested that software engineers in the open source movement may have sub-groupings which parallel kinship groups such as lineages. Within such groups gift giving is not necessarily or directly reciprocated, instead members work according to the ‘axiom of kinship amity’—direct economic calculation is not appropriate within the group. What Bourdieu calls ‘symbolic capital’ can be used to understand how people work in order to enhance the reputation (of themselves and their group).

The T allele of a single-nucleotide polymorphism 13.9 kb upstream of the lactase gene (LCT) (C-13.9kbT) does not predict or cause the lactase-persistence phenotype in Africans

The ability to digest the milk sugar lactose as an adult (lactase persistence) is a variable genetic trait in human populations. The lactase-persistence phenotype is found at low frequencies in the majority of populations in sub-Saharan Africa that have been tested, but, in some populations, particularly pastoral groups, it is significantly more frequent. Recently, a CT polymorphism located 13.9 kb upstream of exon 1 of the lactase gene (LCT) was shown in a Finnish population to be closely associated with the lactase-persistence phenotype (Enattah et al. 2002). We typed this polymorphism in 1,671 individuals from 20 distinct cultural groups in seven African countries. It was possible to match seven of the groups tested with groups from the literature for whom phenotypic information is available. In five of these groups, the published frequencies of lactase persistence are >/=25%. We found the T allele to be so rare that it cannot explain the frequency of the lactase-persistence phenotype throughout Africa. By use of a statistical procedure to take phenotyping and sampling errors into account, the T-allele frequency was shown to be significantly different from that predicted in five of the African groups. Only the Fulbe and Hausa from Cameroon possessed the T allele at a level consistent with phenotypic observations (as well as an Irish sample used for comparison). We conclude that the C-13.9kbT polymorphism is not a predictor of lactase persistence in sub-Saharan Africans. We also present Y-chromosome data that are consistent with previously reported evidence for a back-migration event into Cameroon, and we comment on the implications for the introgression of the -13.9kb*T allele.

Prevalence of Clinically Relevant UGT1A Alleles and Haplotypes in African Populations

Variation of a short (TA)n repeat sequence (rs8175347) covering the TATA box of UGT1A1 (UDP‐glucuronosyltransferase1A1) is associated with hyperbilirubinaemia (Gilberts syndrome) and adverse drug reactions, and is used for dosage advice for irinotecan. Several reports indicate that the low‐activity (risk) alleles ((TA)7 and (TA)8)) are very frequent in Africans but the patterns of association with other variants in the UGT1A gene complex that may modulate these responses are not well known. rs8175347 and two other clinically relevant UGT1A variants (rs11692021 and rs10929302) were assayed in 2616 people from Europe and Africa. Low‐activity (TA)n alleles frequencies were highest in equatorial Africa, (TA)7, being the most common in Cameroon, Ghana, southern Sudan, and in Ethiopian Anuak. Haplotypic diversity was also greatest in equatorial Africa, but in Ethiopia was very variable across ethnic groups. Resequencing of the promoter of a sample subset revealed no novel variations, but rs34547608 and rs887829 were typed and shown to be tightly associated with (TA)n. Our results illustrate the need for investigation of the effect of UGT1A variants other than (TA)n on the risk of irinotecan toxicity, as well as hyperbilirubinaemia due to hemolytic anaemia or human immunodeficiency virus protease inhibitors, so that appropriate pharmacogenetic advice can be given.

The potentially deleterious functional variant flavin-containing monooxygenase 2*1 is at high frequency throughout sub-Saharan Africa

Background The drug-metabolizing enzyme flavin-containing monooxygenase 2 (FMO2) is the predominant FMO isoform present in the lung of most mammals, including non-human primates. All Europeans and Asians tested have been shown to be homozygous for a non-functional variant, FMO2*2A, which contains a premature stop codon due to a single-nucleotide change in exon 9 (g.23238C>T). The ancestral allele, FMO2*1, encodes a functionally active protein and has been found in African–Americans (26%) and Hispanics (2% to 7%). Possessing this variant increases the risk of pulmonary toxicity when exposed to thioureas, a widely used class of industrial compounds. FMO2 may also be involved in the metabolism of drugs that are used to treat diseases that are prevalent in Africa. Results and Conclusion We conducted a survey of g.23238C>T variation across Africa that revealed that the distribution of this SNP is relatively homogeneous across sub-Saharan Africa, with approximately one third of individuals possessing at least one FMO2*1 allele, though in some populations the incidence of these individuals approached 50%. Thus many sub-Saharan Africans may be at substantially increased health risk when encountering thiourea-containing substrates of FMO2. Analysis of HapMap data with the Long-Range Haplotype test found no evidence for positive selection of either 23238C>T allele and maximum-likelihood coalescent analysis indicated that this mutation occurred some 500,000 years before present. This study demonstrates the value of performing genetic surveys in Africa, a continent in which human genetic diversity is thought to be greatest, but where studies of the distribution of this diversity are few.

Little genetic differentiation as assessed by uniparental markers in the presence of substantial language variation in peoples of the Cross River region of Nigeria

BackgroundThe Cross River region in Nigeria is an extremely diverse area linguistically with over 60 distinct languages still spoken today. It is also a region of great historical importance, being a) adjacent to the likely homeland from which Bantu-speaking people migrated across most of sub-Saharan Africa 3000-5000 years ago and b) the location of Calabar, one of the largest centres during the Atlantic slave trade. Over 1000 DNA samples from 24 clans representing speakers of the six most prominent languages in the region were collected and typed for Y-chromosome (SNPs and microsatellites) and mtDNA markers (Hypervariable Segment 1) in order to examine whether there has been substantial gene flow between groups speaking different languages in the region. In addition the Cross River region was analysed in the context of a larger geographical scale by comparison to bordering Igbo speaking groups as well as neighbouring Cameroon populations and more distant Ghanaian communities.ResultsThe Cross River region was shown to be extremely homogenous for both Y-chromosome and mtDNA markers with language spoken having no noticeable effect on the genetic structure of the region, consistent with estimates of inter-language gene flow of 10% per generation based on sociological data. However the groups in the region could clearly be differentiated from others in Cameroon and Ghana (and to a lesser extent Igbo populations). Significant correlations between genetic distance and both geographic and linguistic distance were observed at this larger scale.ConclusionsPrevious studies have found significant correlations between genetic variation and language in Africa over large geographic distances, often across language families. However the broad sampling strategies of these datasets have limited their utility for understanding the relationship within language families. This is the first study to show that at very fine geographic/linguistic scales language differences can be maintained in the presence of substantial gene flow over an extended period of time and demonstrates the value of dense sampling strategies and having DNA of known and detailed provenance, a practice that is generally rare when investigating sub-Saharan African demographic processes using genetic data.

Looking Forward, Looking Back

This paper surveys the disparate literatures on time, and the relative paucity of metaphors available (based on spatial analogues or mirroring past and future onto one another). Parallels between approaches to the past and future are considered and different intellectual traditions surveyed in futurology, memory, history (chronotopes), archaeology and philosophy. Causation across time, how the past affects the present, how the future may affect present and the past are considered as ways of better understanding how tensed statements in time and of time are essential elements of history and of anthropology. Pluralizing is suggested as a positive step: we should be talking of pasts, futures and even of presents. This has consequences, for example, the Thin Red Line of actuality must be broadened to be perhaps the Thick Reddish Braid. As introduction to a special issue of History and Anthropology I consider the papers that follow and how they contribute to the theme.

Sex-Specific Genetic Data Support One of Two Alternative Versions of the Foundation of the Ruling Dynasty of the Nso' in Cameroon.

Sex‐specific genetic data favor a specific variant of the oral history of the kingdom of Nso′ (a Grassfields city‐state in Cameroon) in which the royal family traces its descent from a founding ancestress who married into an autochthonous hunter‐gatherer group. The distributions of Y chromosome and mitochondrial DNA variation in the Nso′ in general and in the ruling dynasty in particular are consistent with specific Nso′ marriage practices, suggesting strict conservation of the royal social class along agnatic lines. This study demonstrates the efficacy of using genetics to augment other sources of information (e.g., oral histories, archaeology, and linguistics) when seeking to recover the histories of African peoples.

ETHNOGENESIS AND FRACTAL HISTORY ON AN AFRICAN FRONTIER: MAMBILA–NJEREP–MANDULU

This paper explores the notion of fractals – structures that display a similar degree of complexity at whatever scale they may be viewed – in relation to investigating African history. A case study of developing ethnicities in the Mambila region of the Nigeria–Cameroon borderland is presented from a fractal perspective: five levels of the history of this region, covering different time, population and physical scales, as well as different objects of explanation for each, are explored. Our general conclusion is that the different scales, or levels, at which one may view history may contain features or imply generalizations that mask features found in, or generalizations implied by, other levels.

Divinatory Logics. Diagnoses and Predictions Mediating Outcomes

This paper is about the logics of how practitioners and their clients use divination in their ongoing involvement with everyday life. It asks philosophical questions of the implications of praxis and suggests that the answers are not always what philosophers might expect. I distinguish two uses or aspects of divinatory usage: that concerned with the present or past, diagnosis, and that concerned with the future, prognosis or prediction. Divinatory practice often contains both aspects; however, the distinction helps our understanding of how divination is used. Examples are taken from Evans-Pritchard on Zande divination (oracles) and from my ongoing work on Mambila spider divination. Some parallels are drawn with ambiguities in financial measures and the ways in which they are used to justify decisions about the systems they “measure.” Social predictions similarly move between styles of usage (exemplified by Merton’s self-fulfilling prophecy). The idea of divinatory logics moves us from the sphere of philosophy to a less rigorously defined sphere of social interaction, where what counts as success may be that we have changed the world so that a statement of fact does not obtain. In a world of counterfactual conditionals, the diviner, not the philosopher, is king.

Performance and agency: the DGB sites of Northern Cameroon

Barich, B.E. 2002. Cultural responses to climatic changes in North Africa: beginning and spread of pastoralism in the Sahara. In Droughts, food and culture: Ecological change and food security in Africa’s later prehistory, ed. F.A. Hassan, 209 223. New York: Kluwer Academic/Plenum. Breunig, P. and K. Neumann. 2002. From hunters and gatherers to food producers: New archaeological and archaeobotanical evidence from the West African Sahel. In Droughts, food and culture: Ecological change and food security in Africa’s later prehistory, ed. F.A. Hassan, 123 155. New York: Kluwer Academic/Plenum. Eggermont, H., D. Verschuren, M. Fagot, B. Rumes, B. Van Bocxlaer and S. Kröpelin. 2008. Aquatic community response in a groundwater-fed desert lake to Holocene desiccation of the Sahara. Quaternary Science Reviews 27: 2411 2425. Heseltine, N. 1959. Toubbou and Gorane: Nomads of the Chad Territory: Notes on their origins. South African Archaeological Bulletin 14: 21 27. Jungstand, G. 2007. ‘Going to greet the relatives’ household economy, mobility and politics in Dar Zaghawa, NE-Chad. In Atlas of cultural and environmental change in arid Africa, eds. O. Bubenzer, A. Bolten and F. Darius, 174 177. Köln: Heinrich-Barth-Institut. Keding, B., T. Lenssen-Erz and A. Pastoors. 2007. Pictures and pots from pastoralists: Investigations into the prehistory of the Ennedi highlands in NE Chad. Sahara 18: 23 46. Kröpelin, S. 2004. New petroglyph sites in the Southern Libyan Desert (Sudan-Chad). Sahara 15: 111 118. Kröpelin, S. 2007a. High-resolution climate archives in the Sahara (Ounianga, Chad). In Atlas of cultural and environmental change in arid Africa, eds. O. Bubenzer, A. Bolten and F. Darius, 56 57. Köln: Heinrich-Barth-Institut. Kröpelin, S. 2007b. Reconnaissance of the Erdi Ma (northeast Chad). In Atlas of cultural and environmental change in arid Africa, eds. O. Bubenzer, A. Bolten and F. Darius, 58 59. Köln: Heinrich-Barth-Institut. Kröpelin, S., D. Verschuren, A.-M. Lézine, H. Eggermont, C. Cocquyt, P. Francus, J.-P. Cazet, M. Fagot, B. Rumes, J.M. Russell, F. Darius, D.J. Conley, M. Schuster, H. von Suchodoletz and D.R. Engstrom. 2008. Climate-driven ecosystem succession in the Sahara: The past 6000 years. Science 320: 765 768. Lenssen-Erz, T. 2007. Ennedi Highlands, Chad artists and herders in a lifeworld on the margins. In Atlas of cultural and environmental change in arid Africa, eds. O. Bubenzer, A. Bolten and F. Darius, 50 53. Köln: Heinrich-Barth-Institut. Neumann, K. 1989. Holocene vegetation of the Eastern Sahara: Charcoal from prehistoric sites. African Archaeological Review 7: 97 116.