scholarly journals Mozambican genetic variation provides new insights into the Bantu expansion

2019 ◽  
Author(s):  
Armando Semo ◽  
Magdalena Gayà-Vidal ◽  
Cesar Fortes-Lima ◽  
Bérénice Alard ◽  
Sandra Oliveira ◽  
...  
Keyword(s):  
Iron Age ◽  
Genetic Relationships ◽  
Central Africa ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Nucleotide Polymorphisms ◽  
Wide Range ◽  
The Rich ◽  
Sub Saharan ◽  
Genetic Substructure

AbstractThe Bantu expansion, which started in West Central Africa around 5,000 BP, constitutes a major migratory movement involving the joint spread of peoples and languages across sub-Saharan Africa. Despite the rich linguistic and archaeological evidence available, the genetic relationships between different Bantu-speaking populations and the migratory routes they followed during various phases of the expansion remain poorly understood. Here, we analyze the genetic profiles of southwestern and southeastern Bantu-speaking peoples located at the edges of the Bantu expansion by generating genome-wide data for 200 individuals from 12 Mozambican and 3 Angolan populations using ∼1.9 million autosomal single nucleotide polymorphisms. Incorporating a wide range of available genetic data, our analyses confirm previous results favoring a “late split” between West and East Bantu speakers, following a joint passage through the rainforest. In addition, we find that Bantu speakers from eastern Africa display genetic substructure, with Mozambican populations forming a gradient of relatedness along a North-South cline stretching from the coastal border between Kenya and Tanzania to South Africa. This gradient is further associated with a southward increase in genetic homogeneity, and involved minimum admixture with resident populations. Together, our results provide the first genetic evidence in support of a rapid North-South dispersal of Bantu peoples along the Indian Ocean Coast, as inferred from the distribution and antiquity of Early Iron Age assemblages associated with the Kwale archaeological tradition.

scholarly journals Along the Indian Ocean Coast: Genomic Variation in Mozambique Provides New Insights into the Bantu Expansion

2019 ◽  
Vol 37 (2) ◽  
pp. 406-416 ◽  
Author(s):  
Armando Semo ◽  
Magdalena Gayà-Vidal ◽  
Cesar Fortes-Lima ◽  
Bérénice Alard ◽  
Sandra Oliveira ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Iron Age ◽  
Genetic Relationships ◽  
Central Africa ◽  
Genomic Variation ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Nucleotide Polymorphisms ◽  
Wide Range ◽  
The Indian Ocean

Abstract The Bantu expansion, which started in West Central Africa around 5,000 BP, constitutes a major migratory movement involving the joint spread of peoples and languages across sub-Saharan Africa. Despite the rich linguistic and archaeological evidence available, the genetic relationships between different Bantu-speaking populations and the migratory routes they followed during various phases of the expansion remain poorly understood. Here, we analyze the genetic profiles of southwestern and southeastern Bantu-speaking peoples located at the edges of the Bantu expansion by generating genome-wide data for 200 individuals from 12 Mozambican and 3 Angolan populations using ∼1.9 million autosomal single nucleotide polymorphisms. Incorporating a wide range of available genetic data, our analyses confirm previous results favoring a “late split” between West and East Bantu speakers, following a joint passage through the rainforest. In addition, we find that Bantu speakers from eastern Africa display genetic substructure, with Mozambican populations forming a gradient of relatedness along a North–South cline stretching from the coastal border between Kenya and Tanzania to South Africa. This gradient is further associated with a southward increase in genetic homogeneity, and involved minimum admixture with resident populations. Together, our results provide the first genetic evidence in support of a rapid North–South dispersal of Bantu peoples along the Indian Ocean Coast, as inferred from the distribution and antiquity of Early Iron Age assemblages associated with the Kwale archaeological tradition.

scholarly journals Ancient DNA reveals a multistep spread of the first herders into sub-Saharan Africa

Science ◽  
2019 ◽  
Vol 365 (6448) ◽  
pp. eaaw6275 ◽  
Author(s):  
Mary E. Prendergast ◽  
Mark Lipson ◽  
Elizabeth A. Sawchuk ◽  
Iñigo Olalde ◽  
Christine A. Ogola ◽  
...  
Keyword(s):  
Iron Age ◽  
Food Production ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Multiphase Model ◽  
Later Stone Age ◽  
Genome Wide ◽  
Genome Wide Data ◽  
Sub Saharan ◽  
Pastoral Neolithic

How food production first entered eastern Africa ~5000 years ago and the extent to which people moved with livestock is unclear. We present genome-wide data from 41 individuals associated with Later Stone Age, Pastoral Neolithic (PN), and Iron Age contexts in what are now Kenya and Tanzania to examine the genetic impacts of the spreads of herding and farming. Our results support a multiphase model in which admixture between northeastern African–related peoples and eastern African foragers formed multiple pastoralist groups, including a genetically homogeneous PN cluster. Additional admixture with northeastern and western African–related groups occurred by the Iron Age. These findings support several movements of food producers while rejecting models of minimal admixture with foragers and of genetic differentiation between makers of distinct PN artifacts.

scholarly journals Should seasonal rainfall forecasts be used for flood preparedness?

2017 ◽  
Vol 21 (9) ◽  
pp. 4517-4524 ◽  
Author(s):  
Erin Coughlan de Perez ◽  
Elisabeth Stephens ◽  
Konstantinos Bischiniotis ◽  
Maarten van Aalst ◽  
Bart van den Hurk ◽  
...  
Keyword(s):  
Central Africa ◽  
Sub Saharan Africa ◽  
Seasonal Rainfall ◽  
Eastern Africa ◽  
Total Rainfall ◽  
Climate Services ◽  
Dry Spells ◽  
Flood Preparedness ◽  
Sub Saharan ◽  
Seasonal Rainfall Forecasts

Abstract. In light of strong encouragement for disaster managers to use climate services for flood preparation, we question whether seasonal rainfall forecasts should indeed be used as indicators of the likelihood of flooding. Here, we investigate the primary indicators of flooding at the seasonal timescale across sub-Saharan Africa. Given the sparsity of hydrological observations, we input bias-corrected reanalysis rainfall into the Global Flood Awareness System to identify seasonal indicators of floodiness. Results demonstrate that in some regions of western, central, and eastern Africa with typically wet climates, even a perfect tercile forecast of seasonal total rainfall would provide little to no indication of the seasonal likelihood of flooding. The number of extreme events within a season shows the highest correlations with floodiness consistently across regions. Otherwise, results vary across climate regimes: floodiness in arid regions in southern and eastern Africa shows the strongest correlations with seasonal average soil moisture and seasonal total rainfall. Floodiness in wetter climates of western and central Africa and Madagascar shows the strongest relationship with measures of the intensity of seasonal rainfall. Measures of rainfall patterns, such as the length of dry spells, are least related to seasonal floodiness across the continent. Ultimately, identifying the drivers of seasonal flooding can be used to improve forecast information for flood preparedness and to avoid misleading decision-makers.

scholarly journals Should seasonal rainfall forecasts be used for flood preparedness?

2017 ◽  
Author(s):  
Erin Coughlan de Perez ◽  
Elisabeth Stephens ◽  
Konstantinos Bischiniotis ◽  
Maarten van Aalst ◽  
Bart van den Hurk ◽  
...  
Keyword(s):  
Central Africa ◽  
Sub Saharan Africa ◽  
Seasonal Rainfall ◽  
Eastern Africa ◽  
Total Rainfall ◽  
Climate Services ◽  
West And Central Africa ◽  
Flood Preparedness ◽  
Sub Saharan ◽  
Seasonal Rainfall Forecasts

Abstract. In light of strong encouragement for disaster managers to use climate services for flood preparation, we question whether seasonal rainfall forecasts should indeed be used as indicators of the likelihood of flooding. Here, we investigate the primary drivers of flooding at the seasonal timescale across sub-Saharan Africa. Given the sparsity of hydrological observations, we input bias-corrected reanalysis rainfall into the Global Flood Awareness System to identify seasonal indicators of floodiness. Results demonstrate that in wet climates, even a perfect tercile forecast of seasonal total rainfall would provide little to no indication of the seasonal likelihood of flooding. The number of extreme events within a season shows the highest correlations with floodiness consistently across regions. Otherwise, results vary across climate regimes: floodiness in arid regions in Southern and Eastern Africa shows the strongest correlations with seasonal average soil moisture and seasonal total rainfall. Floodiness in wetter climates of West and Central Africa and Madagascar shows the strongest relationship with measures of the intensity of seasonal rainfall. Measures of rainfall patterns, such as the length of dry spells, are least related to seasonal floodiness across the continent. Ultimately, identifying the drivers of seasonal flooding can be used to improve forecast information for flood preparedness, and avoid misleading decision-makers.

scholarly journals Development of sustainable research excellence with a global perspective on infectious diseases: Centre de Recherches Médicales de Lambaréné (CERMEL), Gabon

2021 ◽  
Author(s):  
Michael Ramharter ◽  
Selidji T. Agnandji ◽  
Ayôla A. Adegnika ◽  
Bertrand Lell ◽  
Ghyslain Mombo-Ngoma ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Medical Research ◽  
Medical Care ◽  
Central Africa ◽  
International Standards ◽  
Global Perspective ◽  
Sub Saharan Africa ◽  
Wide Range ◽  
Sub Saharan

SummaryMedical research in sub-Saharan Africa is of high priority for societies to respond adequately to local health needs. Often enough it remains a challenge to build up capacity in infrastructure and human resources to highest international standards and to sustain this over mid-term to long-term periods due to difficulties in obtaining long-term institutional core funding, attracting highly qualified scientists for medical research and coping with ever changing structural and political environments. The Centre de Recherches Médicales de Lambaréné (CERMEL) serves as model for how to overcome such challenges and to continuously increase its impact on medical care in Central Africa and beyond. Starting off as a research annex to the Albert Schweitzer Hospital in Lambaréné, Gabon, it has since then expanded its activities to academic and regulatory clinical trials for drugs, vaccines and diagnostics in the field of malaria, tuberculosis, and a wide range of poverty related and neglected tropical infectious diseases. Advancing bioethics in medical research in Africa and steadily improving its global networks and infrastructures, CERMEL serves as a reference centre for several international consortia. In close collaboration with national authorities, CERMEL has become one of the main training hubs for medical research in Central Africa. It is hoped that CERMEL and its leitmotiv “to improve medical care for local populations” will serve as an inspiration to other institutions in sub-Saharan Africa to further increase African capacity to advance medicine.

scholarly journals Addressing Pediatric HIV Pretreatment Drug Resistance and Virologic Failure in Sub-Saharan Africa: A Cost-Effectiveness Analysis of Diagnostic-Based Strategies in Children ≥3 Years Old

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 567
Author(s):  
Mutita Siriruchatanon ◽  
Shan Liu ◽  
James G. Carlucci ◽  
Eva A. Enns ◽  
Horacio A. Duarte
Keyword(s):  
Drug Resistance ◽  
Cost Effectiveness ◽  
Virologic Failure ◽  
Pediatric Hiv ◽  
Sub Saharan Africa ◽  
Financial Investment ◽  
Switching Strategy ◽  
Wide Range ◽  
Sub Saharan ◽  
Living With Hiv

Improvement of antiretroviral therapy (ART) regimen switching practices and implementation of pretreatment drug resistance (PDR) testing are two potential approaches to improve health outcomes for children living with HIV. We developed a microsimulation model of disease progression and treatment focused on children with perinatally acquired HIV in sub-Saharan Africa who initiate ART at 3 years of age. We evaluated the cost-effectiveness of diagnostic-based strategies (improved switching and PDR testing), over a 10-year time horizon, in settings without and with pediatric dolutegravir (DTG) availability as first-line ART. The improved switching strategy increases the probability of switching to second-line ART when virologic failure is diagnosed through viral load testing. The PDR testing strategy involves a one-time PDR test prior to ART initiation to guide choice of initial regimen. When DTG is not available, PDR testing is dominated by the improved switching strategy, which has an incremental cost-effectiveness ratio (ICER) of USD 579/life-year gained (LY), relative to the status quo. If DTG is available, improved switching has a similar ICER (USD 591/LY) relative to the DTGstatus quo. Even when substantial financial investment is needed to achieve improved regimen switching practices, the improved switching strategy still has the potential to be cost-effective in a wide range of sub-Saharan African countries. Our analysis highlights the importance of strengthening existing laboratory monitoring systems to improve the health of children living with HIV.

scholarly journals Kelch 13-propeller polymorphisms in Plasmodium falciparum from Jazan region, southwest Saudi Arabia

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Ommer Mohammed Dafalla ◽  
Mohammed Alzahrani ◽  
Ahmed Sahli ◽  
Mohammed Abdulla Al Helal ◽  
Mohammad Mohammad Alhazmi ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Saudi Arabia ◽  
Parasite Clearance ◽  
Sub Saharan Africa ◽  
Local Alignment ◽  
Nucleotide Polymorphisms ◽  
Gene Encoding ◽  
Synonymous Mutations ◽  
Search Tool ◽  
Sub Saharan

Abstract Background Artemisinin-based combination therapy (ACT) is recommended at the initial phase for treatment of Plasmodium falciparum, to reduce morbidity and mortality in all countries where malaria is endemic. Polymorphism in portions of P. falciparum gene encoding kelch (K13)-propeller domains is associated with delayed parasite clearance after ACT. Of about 124 different non-synonymous mutations, 46 have been identified in Southeast Asia (SEA), 62 in sub-Saharan Africa (SSA) and 16 in both the regions. This is the first study designed to analyse the prevalence of polymorphism in the P. falciparum k13-propeller domain in the Jazan region of southwest Saudi Arabia, where malaria is endemic. Methods One-hundred and forty P. falciparum samples were collected from Jazan region of southwest Saudi Arabia at three different times: 20 samples in 2011, 40 samples in 2016 and 80 samples in 2020 after the implementation of ACT. Plasmodium falciparum kelch13 (k13) gene DNA was extracted, amplified, sequenced, and analysed using a basic local alignment search tool (BLAST). Results This study obtained 51 non-synonymous (NS) mutations in three time groups, divided as follows: 6 single nucleotide polymorphisms (SNPs) ‘11.8%’ in samples collected in 2011 only, 3 (5.9%) in 2011and 2016, 5 (9.8%) in 2011 and 2020, 5 (9.8%) in 2016 only, 8 (15.7%) in 2016 and 2020, 14 (27.5%) in 2020 and 10 (19.6%) in all the groups. The BLAST revealed that the 2011 isolates were genetically closer to African isolates (53.3%) than Asian ones (46.7%). Interestingly, this proportion changed completely in 2020, to become closer to Asian isolates (81.6%) than to African ones (18.4%). Conclusions Despite the diversity of the identified mutations in the k13-propeller gene, these data did not report widespread artemisinin-resistant polymorphisms in the Jazan region where these samples were collected. Such a process would be expected to increase frequencies of mutations associated with the resistance of ACT.

Cassava Processing in Sub-Saharan Africa: the Implications for Expanding Cassava Production

1994 ◽  
Vol 23 (3) ◽  
pp. 197-205 ◽  
Author(s):  
Felix Izu Nweke
Keyword(s):  
Food Security ◽  
Water Supply ◽  
Sub Saharan Africa ◽  
Wide Range ◽  
Intensive Use ◽  
Cassava Production ◽  
Sub Saharan ◽  
Processing Techniques ◽  
Technical Solutions ◽  
Poor Soil

Cassava makes an important contribution to improving food security and rural incomes in sub-Saharan Africa, as it is tolerant of drought and poor soil and its cultivation does not require much labour. However, the fresh roots are bulky and perishable and need to be processed before they can be marketed; processing also removes the cyanogens which make many varieties poisonous in their raw form. Cassava roots are turned into granules, flours, pastes and chips, with a wide range of flavours and appearances for different areas and markets. Many different processing techniques are used, some of which make intensive use of fuelwood while others require a plentiful water supply. These requirements, as well as the need for a good transport and marketing infrastructure, limit the expansion of cassava production in sub-Saharan Africa, but technical solutions are being found.

Women in Gabon

2021 ◽  
Author(s):  
Claire H. Griffiths
Keyword(s):  
Central Africa ◽  
Early Period ◽  
Sub Saharan Africa ◽  
African Women ◽  
Female Population ◽  
History Of ◽  
Sub Saharan ◽  
Tropical Woods ◽  
New Research ◽  
Export Revenue

Gabon, a small oil-rich country straddling the equator on the west coast of Africa, is the wealthiest of France’s former colonies. An early period of colonization in the 19th century resulted in disease, famine, and economic failure. The creation of French Equatorial Africa in 1910 marked the beginning of the sustained lucrative exploitation of Gabon’s natural resources. Gabon began off-shore oil production while still a colony of France. Uranium was also discovered in the last decade of the French Equatorial African empire. Coupled with rich reserves in tropical woods, Gabon has achieved, since independence in 1960, a higher level of export revenue per capita of population than any other country in sub-Saharan Africa in the postcolonial era. However, significant inequality has characterized access to wealth through paid employment throughout the recorded history of monetized labor. While fortunes have been amassed by a minute proportion of the female population of Gabon associated with the ruling regime, and a professional female middle-class has emerged, inequalities of opportunity and reward continue to mark women’s experience of life in this little-known country of West Central Africa. The key challenge facing scholars researching the history of women in Gabon remains the relative lack of historical resources. While significant strides have been made over the past decade, research on women’s history in Francophone Africa published in English or French remains embryonic. French research on African women began to make a mark in the last decade of colonization, notably with the work of Denise Paulme, but then remained a neglected area for decades. The publication in 1994 of Les Africaines by French historian Catherine Coquery-Vidrovitch was hailed at the time as a pioneering work in French historiography. But even this new research contained no analysis of and only a passing reference to women in Gabon.

scholarly journals Africa and the wider world: creole communities in the Atlantic and Indian Oceans

Tempo ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 465-481
Author(s):  
Malyn Newitt
Keyword(s):  
Technology Transfer ◽  
Indian Ocean ◽  
World Economy ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Cultural Appropriation ◽  
The World ◽  
African Slaves ◽  
The Indian Ocean ◽  
Sub Saharan

Abstract: Portuguese creoles were instrumental in bringing sub-Saharan Africa into the intercontinental systems of the Atlantic and Indian Ocean. In the Atlantic Islands a distinctive creole culture emerged, made up of Christian emigrants from Portugal, Jewish exiles and African slaves. These creole polities offered a base for coastal traders and became politically influential in Africa - in Angola creating their own mainland state. Connecting the African interior with the world economy was largely on African terms and the lack of technology transfer meant that the economic gap between Africa and the rest of the world inexorably widened. African slaves in Latin America adapted to a society already creolised, often through adroit forms of cultural appropriation and synthesis. In eastern Africa Portuguese worked within existing creolised Islamic networks but the passage of their Indiamen through the Atlantic created close links between the Indian Ocean and Atlantic commercial systems.

Sign in / Sign up

Export Citation Format

Share Document