Diversity In Africa Research Articles

Composition and diversity of the spider fauna in the canopy of a montane forest in Tanzania

Spiders were sampled using insecticide knockdown in an African montane forest in the Uzungwa Mountains of Tanzania. The results are used to discuss the faunal composition at the site and in comparison to other sites, and the implications of the results for estimating spider diversity in Africa are discussed. A total of 5233 adults comprising 149 species were collected from 11 samples covering a total of 906 m2 of projected area. Three species contributed 45% of the sample. Previous insecticide knockdown studies of tropical lowland forest canopies have shown a dominance of Theridiidae, Salticidae and Araneidae. In the present study Linyphiidae dominated in abundance and were the second most diverse in terms of species richness. Other abundant families were Oonopidae and Pholcidae, while Theridiidae, Salticidae and Araneidae were rich in species. This supports a previous study, which indicated that the importance of linyphiids increases with altitude. Species richness was predicted using a number of estimators, which produced relatively similar results. Using the abundance-based estimator, Chao 1, the predicted richness for the total area sampled is 183 ± 15 species. This indicates that at least 20% of the area's spider community remains unsampled. A high ratio of undescribed species (approximately 80%) and a relatively high species turnover compared to a site 20 km away within the same forest complex suggests that the number of spiders in Africa could well be much higher than the current, published estimate of 20000 species.

The distribution of cultural and biological diversity in Africa.

Anthropologists, biologists and linguists have all noted an apparent coincidence in species diversity and human cultural or linguistic diversity. We present, to our knowledge, one of the first quantitative descriptions of this coincidence and show that, for 2 degrees x 2 degrees grid cells across sub-Saharan Africa, cultural diversity and vertebrate species diversity exhibit marked similarities in their overall distribution. In addition, we show that 71% of the observed variation in species richness and 36% in language richness can be explained on the basis of environmental factors, suggesting that similar factors, especially those associated with rainfall and productivity, affect the distributions of both species and languages. Nevertheless, the form of the relationships between species richness and language richness and environmental factors differs, and it is unlikely that comparable mechanisms underpin the similar patterns of species and language richness. Moreover, the fact that the environmental factors considered here explain less than half of the variation in language richness indicates that other factors, many of which are likely to be historical or social, also influence the distribution of languages.

Restricted genetic and antigenic diversity of Plasmodium falciparum under mesoendemic transmission in the Venezuelan Amazon.

The study of genetic diversity in malaria populations is expected to provide new insights for the deployment of control measures. Plasmodium falciparum diversity in Africa and Asia is thought to reflect endemicity. In comprehensive epidemiological surveys reported here the genetic and antigenic structure of P. falciparum in the Venezuelan Amazon were studied over a 2-year period. DNA polymorphisms in glutamate-rich protein (GLURP), merozoite-surface protein 1 (MSP1) and MSP2 genes, in a multicopy element (PfRRM), all showed low diversity, 1 predominant genotype, and virtually no multi-clonal infections. Moreover, linkage disequilibrium was seen between GLURP, MSP1 and MSP2. Specific antibody responses against MSP1 and MSP2 recombinant antigens reflected the low genetic diversity observed in the parasite population. This is unexpected in a mesoendemic area, and suggests that the low diversity here may not only relate to endemicity but to other influences such as a bottleneck effect. Linkage disequilibrium and a predominant genotype may imply that P. falciparum frequently propagates with an epidemic or clonal population structure in the Venezuelan Amazon.

Who Am I, and Why Am I Different?

"Hey Daktari, they need you over in medical right away." This, thankfully, pulled me from a staff meeting on budgets to take care of a volunteer who had been assaulted and had a head laceration. The story behind this unfortunate event started me thinking about the subject of diversity in Africa.

Why are there so many civil wars in Africa? Understanding and preventing violent conflict

Contrary to popular belief, Africa's civil wars are not due to its ethnic and religious diversity. Using recently developed models of the overall incidence of civil wars in 161 countries between 1960 and 1999, we draw lessons with special reference to Africa, showing that the relatively higher incidence of war in Africa is not due to the ethno-linguistic fragmentation of its countries, but rather to high levels of poverty, failed political institutions and economic dependence on natural resources. We argue that the best and fastest strategy to reduce the incidence of civil war in Africa and prevent future civil wars is to institute democratic reforms that effectively manage the challenges facing Africa's diverse societies. To promote inter-group cooperation in Africa, specially tailored political governance and economic management institutions are needed, and we advance some hypotheses on the nature of such institutions. We suggest that Africa's ethnic diversity in fact helps - rather than impedes - the emergence of stable development as it necessitates inter-group bargaining processes. These processes can be peaceful if ethnic groups feel adequately represented by their national political institutions and if the economy provides opportunity for productive activity.

A View of Modern Human Origins from Y Chromosome Microsatellite Variation

The idea that all modern humans share a recent (within the last 150, 000 years) African origin has been proposed and supported on the basis of three observations. Most genetic loci examined to date have (1) shown greater diversity in African populations than in others, (2) placed the first branch between African and all non-African populations in phylogenetic trees, and (3) indicated recent dates for either the molecular coalescence (with the exception of some autosomal and X-chromosomal loci) or for the time of separation between African and non-African populations. We analyze variation at 10 Y chromosome microsatellite loci that were typed in 506 males representing 49 populations and every inhabited continent and find significantly greater Y chromosome diversity in Africa than elsewhere, find the first branch in phylogenetic trees of the continental populations to fall between African and all non-African populations, and date this branching with the (deltamu)2 distance measure to 5800-17,400 or 12,800-36,800 years BP depending on the mutation rate used. The magnitude of the excess Y chromosome diversity in African populations appears to result from a greater antiquity of African populations rather than a greater long-term effective population size. These observations are most consistent with a recent African origin for all modern humans.

DNA sequence variation in a non-coding region of low recombination on the human X chromosome.

DNA sequence variation has become a major source of insight regarding the origin and history of our species as well as an important tool for the identification of allelic variants associated with disease. Comparative sequencing of DNA has to date focused mainly on mitochondrial (mt) DNA, which due to its apparent lack of recombination and high evolutionary rate lends itself well to the study of human evolution. These advantages also entail limitations. For example, the high mutation rate of mtDNA results in multiple substitutions that make phylogenetic analysis difficult and, because mtDNA is maternally inherited, it reflects only the history of females. For the history of males, the non-recombining part of the paternally inherited Y chromosome can be studied. The extent of variation on the Y chromosome is so low that variation at particular sites known to be polymorphic rather than entire sequences are typically determined. It is currently unclear how some forms of analysis (such as the coalescent) should be applied to such data. Furthermore, the lack of recombination means that selection at any locus affects all 59 Mb of DNA. To gauge the extent and pattern of point substitutional variation in non-coding parts of the human genome, we have sequenced 10 kb of non-coding DNA in a region of low recombination at Xq13.3. Analysis of this sequence in 69 individuals representing all major linguistic groups reveals the highest overall diversity in Africa, whereas deep divergences also exist in Asia. The time elapsed since the most recent common ancestor (MRCA) is 535,000+/-119,000 years. We expect this type of nuclear locus to provide more answers about the genetic origin and history of humans.

REPTILE SYSTEMATIC STUDIES IN SOUTHERN AFRICA: A BRIEF HISTORY AND OVERVIEW

SUMMARY Southern Africa has the richest reptile diversity in Africa, with a fauna that currently exceeds 490 species. Present rates of discovery, which for lizards are still comparable to those in the early phases of exploration, indicate that the fauna may approach, if not exceed, 600 species. Lizards form the dominant component (60.9%) of the reptile fauna. The 578 recognised taxa (species and subspecies) were described by 101 authors, of which 12 authors were responsible for 12 or more taxa and together named 68.9% of the total taxa. The five most productive authors were, in order: A. Smith, W. Peters, D. Broadley, J. Hewitt, and V. FitzSimons. The contributions of these authors, the growth in herpetological studies in the last 25 years, and the importance of regional surveys in the development of biogeographic models, are summarised. Over 50 species of reptile have very restricted distributions (less than 3 quarter-degree grid squares) and may be of conservation concern. Despite national rhetoric evincing concern for the biodiversity crisis, there has been a recent decline in herpetological posts and manpower.

Out of Africa and back again: nested cladistic analysis of human Y chromosome variation.

We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544 individuals from Africa, Asia, Europe, Oceania, and the New World. Phylogenetic analyses of these nine sites resulted in a tree for 10 distinct Y haplotypes with a coalescence time of approximately 150,000 years. The 10 haplotypes were unevenly distributed among human populations: 5 were restricted to a particular continent, 2 were shared between Africa and Europe, 1 was present only in the Old World, and 2 were found in all geographic regions surveyed. The ancestral haplotype was limited to African populations. Random permutation procedures revealed statistically significant patterns of geographical structuring of this paternal genetic variation. The results of a nested cladistic analysis indicated that these geographical associations arose through a combination of processes, including restricted, recurrent gene flow (isolation by distance) and range expansions. We inferred that one of the oldest events in the nested cladistic analysis was a range expansion out of Africa which resulted in the complete replacement of Y chromosomes throughout the Old World, a finding consistent with many versions of the Out of Africa Replacement Model. A second and more recent range expansion brought Asian Y chromosomes back to Africa without replacing the indigenous African male gene pool. Thus, the previously observed high levels of Y chromosomal genetic diversity in Africa may be due in part to bidirectional population movements. Finally, a comparison of our results with those from nested cladistic analyses of human mtDNA and beta-globin data revealed different patterns of inferences for males and females concerning the relative roles of population history (range expansions) and population structure (recurrent gene flow), thereby adding a new sex-specific component to models of human evolution.

Genetic diversity in Africa: An analysis of HLA class II allele frequencies in 18 different villages in six African countries

Genetic diversity in Africa: An analysis of HLA class II allele frequencies in 18 different villages in six African countries

A comparison of the efficacy of higher taxa and species numbers in the assessment of biodiversity in the neotropics

The neotropical region as a whole is much more species diverse than the palaeotropics but no more diverse at the family and only slightly at the generic level. Only 6.4% of neotropical species belong to plant families that are confined to the region and there is a greater generic diversity in Africa than in the neotropics indicating that species are much better indicators of total diversity. The striking difference in species make up between the northern Andean region and Amazonia is important to recognize in conservation planning. In the northern Andean region, herbs and shrubs with Andean-centred distributions predominate whereas in Amazonia, trees and shrubs with Amazonian-centred distributions predominate. The analysis of species distributions show both centres of endemism and centres of diversity which are not apparent when only higher taxa are considered. The local demography of species varies considerably within the lowland rainforest regions and this is discussed using data from quantitative inventories. It is concluded that accurate assessment of the taxon component of biodiversity of the neotropics must be based at the species level rather than at that of higher taxa, and that species data are a valuable tool for conservation planning.

Antigenic evidence of the presence of the aberrant HIV-1ANT70 virus in Cameroon and Gabon

The search for an effective vaccine against HIV-1 is of major importance. Some promising research has been conducted on the V3 loop peptides of HIV-1 in chimpanzees. In this article are reported the results of a research project on the prevalence of sera collected from HIV-1 positive people in Cameroon Gabon Ivory Coast and Kenya which are reactive to a genetically divergent HIV-1 V3 peptide isolate (ANT70) and peptides obtained from 3 other HIV-1 isolates. A total of 895 serum samples were tested using the V3-peptide enzyme-linked immunosorbent assay (ELISA). 40 HIV-1 seronegative sera 10 from each country were used as negative controls. Overall 88% (787/895) of the sera reacted with the V3 loop of MN peptide 246 (27%) sera reacted with the MAL peptide and 53% (471/895) reacted with the Z6 peptide component of the V3 loop. A total of 14 (14/895) sera (9 from Cameroon and 5 from Gabon) reacted with the ANT70 peptide ELISA. The authors suggest that their results should prompt further investigation in mapping antigenic diversity in Africa and that this knowledge is necessary in the development of an HIV-1 vaccine.

Evolution of human papillomavirus type 18: an ancient phylogenetic root in Africa and intratype diversity reflect coevolution with human ethnic groups

Papillomaviruses are an ideal model system for the study of DNA virus evolution. On several levels, phylogenetic trees of papillomaviruses reflect the relationship of their hosts. Papillomaviruses isolated from remotely related vertebrates form major branches. One branch of human papillomaviruses (HPVs) includes an ape and two monkey papillomaviruses, possibly because the diversification of the viruses predated the separation of the infected-primate taxa. This hypothesis predicts that the root of the evolution of some if not all HPV types should point to Africa, since humans evolved from nonhuman primates in this continent. We tested this hypothesis and compared the genomic sequences of HPV type 18 (HPV-18) isolates from four continents. Diversity within HPV-18 correlates with patterns of the evolution and spread of Homo sapiens: HPV-18 variants, just like HPV-16 variants, are specific for the major human races, with maximal diversity in Africa. Outgroup rooting of the HPV-18 tree against HPV-45, which is closely related to HPV-18, identifies African HPV-18 variants at the root of the tree. The identification of an African HPV-45 isolate further reduces the evolutionary distance between HPV-18 and HPV-45. HPV-18 variants from Amazonian Indians are the closest relatives to those from Japanese and Chinese patients and suggest that a single point mutation in the phylogenetically evaluated genomic segment represents at least 12,000 years of evolution. We estimate that diversity within HPV-18 and probably within other HPV types evolved over a period of more than 200,000 years and that diversity between HPV types evolved over several million years.

Reforming Peasant Production in Africa: Power and Technological Change in Two Nigerian Villages

Differential access to state-allocated incentives, based on socio-economic inequalities in rural society, is commonly assumed to be a key determinant of change in rural Africa. This article argues that, given the spatial diversity of Africa's rural political economies, analysis of the politics of rural change needs to be premised on an appreciation of the multiplicity of social relations through which rural power structures are configured. Data from a field study of a World Bank assisted agricultural development project in Lafia, Nigeria, are used to illustrate the manner in which spatial and inter-community variations in responses to commercialization, cultural divisions and the reorganization of political relations during the colonial era combine to sustain regional power structures which are defined by such differences. A comparative analysis of two village communities at opposite ends of the regional spectrum of commercialization is employed to demonstrate how such power structures provide a framework within which the political conditions of access operate to the advantage of both dominant socio-economic strata and members of particular cultural communities.

A New South American Species of Sacciolepis (Poaceae: Panicoideae: Paniceae), with a Summary of the Genus in the New World

The new South American species Sacciolepis otachyrioides is described and illus- trated; it is related to S. myuros, but differs in smaller inflorescences and broader, more indurate, and obscurely-nerved spikelets. A key and summary of all six New World species of Sacciolepis is presented. Sacciolepis Nash in Britton is a genus of about 30 species distributed worldwide in moist to wet sites in warm temperate and tropical re- gions, but with a center of diversity in Africa (Clayton and Renvoize 1986; Simon 1972). A segregate of Panicum L., Sacciolepis is distin- guished from that large and heterogeneous ge- nus by the following characters: 1) a densely spicate panicle; 2) spikelets with the upper glume or (less commonly) the lower lemma sac- cate at the base; and 3) the upper glume and lower (sterile) lemma strongly nerved. Not all species in Sacciolepis have all three characters, but if at least two of them are present, then inclusion in the genus is warranted. During the course of work on a floristic treat- ment of the grasses for the Flora of the Guia- nas project, abundant material (from BM, BRG,

Knowledge analysis

Commensal rodent species are key reservoirs for Toxoplasma gondii in the domestic environment. In rodents, different T. gondii strains show variable patterns of virulence according to host species. Toxoplasma gondii strains causing non-lethal chronic infections in local hosts will be more likely to persist in a given environment, but few studies have addressed the possible role of these interactions in shaping the T. gondii population structure. In addition, the absence of validated techniques for upstream detection of T. gondii chronic infection in wild rodents hinders exploration of this issue under natural conditions. In this study, we took advantage of an extensive survey of commensal small mammals in three coastal localities of Senegal, with a species assemblage constituted of both native African species and invasive species. We tested 828 individuals for T. gondii chronic infection using the modified agglutination test for antibody detection in serum samples and a quantitative PCR assay for detection of T. gondii DNA in brain samples. The infecting T. gondii strains were genotyped whenever possible by the analysis of 15 microsatellite markers. We found (i) a very poor concordance between molecular detection and serology in the invasive house mouse, (ii) significantly different levels of prevalence by species and (iii) the autochthonous T. gondii Africa 1 lineage strains, which are lethal for laboratory mice, only in the native African species of commensal small mammals. Overall, this study highlights the need to reconsider the use of MAT serology in natural populations of house mice and provides the first known data about T. gondii genetic diversity in invasive and native species of small mammals from Africa. In light of these results, we discuss the role of invasive and native species, with their variable adaptations to different T. gondii strains, in shaping the spatial structure of T. gondii genetic diversity in Africa.

Mitochondrial DNA sequences in single hairs from a southern African population.

Hypervariable parts of mitochondrial DNA (mtDNA) were amplified enzymatically and sequenced directly by using genomic DNA from single plucked human hairs. This method has been applied to study mtDNA sequence variation among 15 members of the !Kung population. A genealogical tree relating these aboriginal, Khoisan-speaking southern Africans to 68 other humans and to one chimpanzee has the deepest branches occurring amongst the !Kung, a result consistent with an African origin of human mtDNA. Fifteen cases of unrelated individuals having identical sequences in the most variable parts of the mtDNA control region were found within populations of !Kung, Western Pygmies, and Eastern Pygmies, but no cases of identity were evident among these populations. This and other evidence of geographic structuring of the mitochondrial diversity in Africa, together with knowledge of the rate of accumulation of base changes in human mtDNA, implies that the average rate at which female lineages have moved their home bases during hunter-gatherer times could be as low as 13 meters per year. The technique of enzymatic amplification and direct sequencing applied to readily collected, highly stable biological materials such as hairs makes it possible to examine with high resolution many representatives of virtually any population.

Skenosis - The Tabernacling of the Word

AbstractThe need for translating the good news of Jesus Christ into a real up-to-date world is recognized by all and sundry. A whole range of terms have been used to designate the need: Africanisation, Localisation, Accomodation, Adaptation, Incarnation, Inculturation, Indigenisation, Aggiornamento. The author, for diverse reasons, offers yet another term Skēnōsis which comes out John 1:14. The term has the merit of being very biblical and emphasizing the dynamic relation and creative tension between the eternal non-negotiable word and the contingent realities of life. Further it underlines the temporary nature of the construct which means skēnōsis must be an on-going process of renewal. The article outlines five major elements of the landscape of the temporal reality of Africa which skēnōsis must engage. Alongside those is set the Word of God which is always received as an interpreted entity, and which is a part of the tradition of the living church. And precisely for that reason there is need for each skēnōsis to engage and be engaged by other attempts in the church universal for mutal correction and affirmation. Some attention is paid to the structures of skēnōsis. The author, however, refuses to do blue-prints particularly because of the diversity in Africa and of Church polity. His interest is only to indicate paths to be explored by each time and place and that in an on-going process.

The SFB-3 macroeconometric model — Theoretical aspects first simulation — and forecasting results: R. Hujer, G. Bauer and H. Knepel: SFB 3, J.W. Goethe-Universität Frankfurt und Universität Mannheim, (March 1982)

This timely research examines the interlink between sustainability and the ideals for economic progress amid the risk and uncertainty that threatens the advancement of agriculture diversity in Africa. Inferences to decision-making parameters based on the availability of new technologies and the implementation of Sustainable Development Goals (SDGs) in the sub-Saharan Africa region from the viewpoint of promoting livelihood are presented. This chapter concludes with the corroboration of the SDG-8 and its impact on the achievement of the SDG-1, 2, 3, 4, 5, 6, 7, and 15. The authors juxtapose sustainable interventions that should proffer competitive solutions to specific societal, social, economic, and environmental challenges. The study recommends several technologies and sustainable initiatives to promote agricultural waste diversity. This chapter contends with sustainable industrial agriculture solutions for developing countries and sub-Saharan Africa in perspective.

A Revision of the Genus Sacciolepis (Gramineae) in the 'Flora Zambesiaca' Area

Summary. An account of the 16 species of Sacciolepis Nash occurring in the 'Flora Zambesiaca' area, with keys, taxonomic notes, histograms, scatter diagrams and maps showing their complete distribution in Africa. Sacciolepis is a pan-tropical genus with a distribution centred on Africa. The aim of this paper is to revise the species confined to the Flora Zambesiaca area and to trace their distribution throughout their range. Sixteen species are delimited out of a total for Africa of about 25 and for the world of about 38. From the herbarium material deposited at Kew it appears that there are two main centres of diversity in Africa, one in South East Tropical Africa (incorporating the Flora Zambesiaca area) and the other in West Tropical Africa. Outside the continent the genus has a few representatives in Madagascar, India, South East Asia, Australia and Tropical America. DELIMITATION OF THE GENUS Sacciolepis belongs to the large well-defined tropical tribe, the Paniceae, characterized by a spikelet containing two florets of which the lower is male or barren, and the upper hermaphrodite. It is delimited from the type genus Panicum by the strongly saccate nature of the base of the upper glume and to a lesser extent of the lower lemma, and by the inflorescence (with the exception of Sacciolepis curvata and its allies) being a false spike (morphologically a much contracted panicle). Sacciolepis may be keyed out from its near relatives Panicum, Ichnanthus, Thyridacne, Hydrothauma, Hymenachne, Cyrtococcum and Setaria as follows: