scholarly journals Magnaporthe oryzae populations in Sub-Saharan Africa are diverse and show signs of local adaptation

2020 ◽  
Author(s):  
Geoffrey Onaga ◽  
Worrawit Suktrakul ◽  
Margaret Wanjiku ◽  
Ian Lorenzo Quibod ◽  
Jean-Baka Domelevo Entfellner ◽  
...  

AbstractRice blast caused by Magnaporthe oryzae is one of the most economically damaging diseases of rice worldwide. The disease originated in Asia but was detected for the first time in Sub-Saharan Africa (SSA) around 100 years ago. Despite its importance, the evolutionary processes involved in shaping the population structure of M. oryzae in SSA remain unclear. In this study, we investigate the population history of M. oryzae using a combined dataset of 180 genomes. Our results show that SSA populations are more diverse than earlier perceived, and harbor all genetic groups previously reported in Asia. While M. oryzae populations in SSA and Asia draw from the same genetic pools, both are experiencing different evolutionary trajectories resulting from unknown selection pressures or demographic processes. The distribution of rare alleles, measured as Tajima’s D values, show significant differences at the substructure level. Genome-wide analysis indicates potential events of population contraction strongly affecting M. oryzae in SSA. In addition, the distribution and haplotype diversity of effectors might suggest a process of local adaptation to SSA conditions. These findings provide additional clues about the evolutionary history of M. oryzae outside the center of origin and help to build customized disease management strategies.

2017 ◽  
Author(s):  
Ranajit Das ◽  
Priyanka Upadhyai

AbstractThe Siddis are a unique Indian tribe of African, South Asian and European ancestry. While their ancestral origins have been traced to the Bantu populations from sub-Saharan Africa, their population history has remained an enigmatic question. Here, we have traced the biogeographical origin of the Siddis employing an admixture based algorithm, Geographical Population Structure (GPS). We evaluated 14 Siddi genomes in reference to 5 African populations from the 1000 Genomes project and 7 Bantu populations from the Human Genome Diversity project. GPS assigned the Siddi genomes to west Zambia and the present-day border between Zimbabwe and northeastern Botswana, overlapping with one of the principal areas of secondary Bantu settlement in Africa, ~1700 years before present (YBP). This is concordant with the secondary Bantu dispersal route from the east African Bantu center that brought the African ancestors of the Siddis to settlement sites in southeast Africa, from where they were disseminated to India, by the Portuguese. Our results also suggest that while the Siddi genomes are significantly different from that of the Bantus, they displayed the highest genomic proximity to the Luhyas and North-East Bantus from Kenya, and that ancestral Siddis are likely to have split from the Luhyas, ~2700 YBP, in congruence with known Bantu expansion and population migration routes. Together with historical, linguistic and anthropological evidences our findings shine light on the genetic relatedness between populations, fine-scale population structure and recapitulate the population history of the Siddis, in the ethnohistorical context of India.


Author(s):  
Brian Stanley

This book charts the transformation of one of the world's great religions during an age marked by world wars, genocide, nationalism, decolonization, and powerful ideological currents, many of them hostile to Christianity. The book traces how Christianity evolved from a religion defined by the culture and politics of Europe to the expanding polycentric and multicultural faith it is today—one whose growing popular support is strongest in sub-Saharan Africa, Latin America, China, and other parts of Asia. The book sheds critical light on themes of central importance for understanding the global contours of modern Christianity, illustrating each one with contrasting case studies, usually taken from different parts of the world. Unlike other books on world Christianity, this one is not a regional survey or chronological narrative, nor does it focus on theology or ecclesiastical institutions. The book provides a history of Christianity as a popular faith experienced and lived by its adherents, telling a compelling and multifaceted story of Christendom's fortunes in Europe, North America, and across the rest of the globe. It demonstrates how Christianity has had less to fear from the onslaughts of secularism than from the readiness of Christians themselves to accommodate their faith to ideologies that privilege racial identity or radical individualism.


2021 ◽  
Vol 13 (3) ◽  
pp. 1158
Author(s):  
Cecilia M. Onyango ◽  
Justine M. Nyaga ◽  
Johanna Wetterlind ◽  
Mats Söderström ◽  
Kristin Piikki

Opportunities exist for adoption of precision agriculture technologies in all parts of the world. The form of precision agriculture may vary from region to region depending on technologies available, knowledge levels and mindsets. The current review examined research articles in the English language on precision agriculture practices for increased productivity among smallholder farmers in Sub-Saharan Africa. A total of 7715 articles were retrieved and after screening 128 were reviewed. The results indicate that a number of precision agriculture technologies have been tested under SSA conditions and show promising results. The most promising precision agriculture technologies identified were the use of soil and plant sensors for nutrient and water management, as well as use of satellite imagery, GIS and crop-soil simulation models for site-specific management. These technologies have been shown to be crucial in attainment of appropriate management strategies in terms of efficiency and effectiveness of resource use in SSA. These technologies are important in supporting sustainable agricultural development. Most of these technologies are, however, at the experimental stage, with only South Africa having applied them mainly in large-scale commercial farms. It is concluded that increased precision in input and management practices among SSA smallholder farmers can significantly improve productivity even without extra use of inputs.


Itinerario ◽  
2014 ◽  
Vol 38 (1) ◽  
pp. 103-124 ◽  
Author(s):  
Alexander Keese

The crossroads of nationalist historiographies in sub-Saharan Africa and of the history of developmentalist attempts that characterise the European late colonial states, have left us with very incomplete images of important trajectories. In the seemingly more “liberal” large colonial empires—notably the French and British—sails were set by 1945 towards a policy of investment and economic change. Some of the scholarly debates question whether this investment was genuine or just a last resort to avoid (rapid) decolonisation; others put the emphasis on inadequate routines of development implemented in these territories, many of which have apparently been continued since decolonisation.In this context, we encounter a clear lack of understanding about how decisions made by individual actors on the administrative level interacted with the larger panorama of social conditions in colonial territories, and of the consequences that these interactions had for the paths towards decolonisation. For a smaller empire such as the Belgian colony of Congo-Léopoldville, these processes are still more obscure; and for the colonies ruled by authoritarian metropoles, as in the cases of territories under Spanish and Portuguese rule, stagnation and absence of change are often taken for granted. In other words, these territories, which were under the rule of metropoles regarded as rather weak in economic terms, are treated as unrepresentative of the broader, European movement towards change in colonial policies. However, the conditions of change towards economic and social modernisation in this latter group of empires, even when inhibited by lack of funding and weak professionalisation of the administration, are frequently very telling for the broader range of challenges that the late colonial states faced.


Author(s):  
Claire H. Griffiths

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.


Author(s):  
Megan Vaughan

This chapter looks at the history of romantic love in Sub-Saharan Africa. This text comes from a lecture given at the British Academy's 2009 Raleigh Lecture on History. This text attempts to explore some of the methodological and theoretical issues involved in an historical study of love in Africa. It argues that romantic love in Africa is not simply an extension of an imperialist cultural and political project and that emotional regimes cannot be divorced from economic circumstances. It explains that though the configurations of interest and emotion take specific forms in African societies, there is nothing peculiarly African about the evident need of individuals to balance realism and idealism in their emotional lives.


2019 ◽  
Vol 37 (3) ◽  
pp. 627-638 ◽  
Author(s):  
Quentin D Sprengelmeyer ◽  
Suzan Mansourian ◽  
Jeremy D Lange ◽  
Daniel R Matute ◽  
Brandon S Cooper ◽  
...  

Abstract A long-standing enigma concerns the geographic and ecological origins of the intensively studied vinegar fly, Drosophila melanogaster. This globally distributed human commensal is thought to originate from sub-Saharan Africa, yet until recently, it had never been reported from undisturbed wilderness environments that could reflect its precommensal niche. Here, we document the collection of 288 D. melanogaster individuals from multiple African wilderness areas in Zambia, Zimbabwe, and Namibia. The presence of D. melanogaster in these remote woodland environments is consistent with an ancestral range in southern-central Africa, as opposed to equatorial regions. After sequencing the genomes of 17 wilderness-collected flies collected from Kafue National Park in Zambia, we found reduced genetic diversity relative to town populations, elevated chromosomal inversion frequencies, and strong differences at specific genes including known insecticide targets. Combining these genomes with existing data, we probed the history of this species’ geographic expansion. Demographic estimates indicated that expansion from southern-central Africa began ∼13,000 years ago, with a Saharan crossing soon after, but expansion from the Middle East into Europe did not begin until roughly 1,800 years ago. This improved model of demographic history will provide an important resource for future evolutionary and genomic studies of this key model organism. Our findings add context to the history of D. melanogaster, while opening the door for future studies on the biological basis of adaptation to human environments.


2010 ◽  
Vol 45 (3) ◽  
pp. 147-159 ◽  
Author(s):  
Cassis Kilian

The history of African film began in the 1960s with the independence of the colonies. Despite all kinds of political and economic difficulties, numerous films have been made since then, featuring wide-ranging processes of consolidation, differentiation and transformation which were characteristic of post-colonial sub-Saharan Africa. However, these feature films should not merely be viewed as back references to specifically African problems. The glimmering fictions are imagination spaces. They preserve ideas about how the post-colonial circumstances should be approached. Seen from this perspective, the history of African film may be studied as a history of African utopias.


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