scholarly journals Estimating the timing of multiple admixture pulses during local ancestry inference

2018 ◽  
Author(s):  
Paloma Medina ◽  
Bryan Thornlow ◽  
Rasmus Nielsen ◽  
Russell Corbett-Detig
Keyword(s):  
Biological Process ◽  
Genetic Material ◽  
Simulated Data ◽  
Sub Saharan Africa ◽  
African Populations ◽  
Fundamental Biological Process ◽  
Admixed Population ◽  
Sub Saharan ◽  
Local Ancestry Inference ◽  
Admixture Event

ABSTRACTAdmixture, the mixing of genetically distinct populations, is increasingly recognized as a fundamental biological process. One major goal of admixture analyses is to estimate the timing of admixture events. Whereas most methods today can only detect the most recent admixture event, here we present coalescent theory and associated software that can be used to estimate the timing of multiple admixture events in an admixed population. We extensively validate this approach and evaluate the conditions under which it can succesfully distinguish one from two-pulse admixture models. We apply our approach to real and simulated data of Drosophila melanogaster. We find evidence of a single very recent pulse of cosmopolitan ancestry contributing to African populations as well as evidence for more ancient admixture among genetically differentiated populations in sub-Saharan Africa. These results suggest our method can quantify complex admixture histories involving genetic material introduced by multiple discrete admixture pulses. The new method facilitates the exploration of admixture and its contribution to adaptation, ecological divergence, and speciation.

scholarly journals Factors associated with oral cavity cancers in Sub-Saharan Africa: Summary of the literature

2021 ◽  
Vol 1 (2) ◽  
pp. 34-41
Author(s):  
A Dieng ◽  
AD Faye ◽  
MM Ndiaye ◽  
G Diop ◽  
A Bouazé ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Public Health Problem ◽  
Epidemiological Data ◽  
Sub Saharan Africa ◽  
Factors Associated ◽  
Manual Search ◽  
African Populations ◽  
Localization Strategy ◽  
Sub Saharan ◽  
Oral Cavity Cancers

INTRODUCTION: Oral cavity cancers are now a public health problem according to WHO epidemiological data. There are several risk factors or factors associated with cancers of the oral cavity but they vary according to geographic regions. OBJECTIVE: The objective of this study was to identify factors associated with cancers of the oral cavity in Sub-Saharan African populations through a systematic literature review. METHODOLOGY: Using the data available for the period from January 1980 to December 2019, a synthesis of the literature was carried out. The literature localization strategy included an electronic search of the MEDLINE, EMBASE and GOOGLE SCHOLAR databases from 1980 to 2019 and a manual search of the list of references of articles identified by snowballing. The data were extracted independently by two researchers on an Excel© spreadsheet. Parameters collected from each study were author, country, type of study, period of study, size, age, gender, and factors studied. RESULTS: Out of 1,318 articles found, 24 were selected. The data contained 17,290 patients including 8,229 men, i.e. a male / female sex-ratio of 0.91. Factors studied were tobacco, alcohol, diet, infection, genetics and social factors. CONCLUSION: The results reported showed that several factors are associated with the occurrence of oral cavity cancers in Sub-Saharan Africa. There is a need to conduct further studies with more structured methodologies for more convincing results.

scholarly journals Motor Neuron Diseases in Sub-Saharan Africa: The Need for More Population-Based Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Emmanuel Quansah ◽  
Thomas K. Karikari
Keyword(s):  
Motor Neuron ◽  
Muscular Atrophy ◽  
Clinical Care ◽  
Treatment Options ◽  
Molecular Genetic ◽  
Population Based ◽  
Sub Saharan Africa ◽  
Motor Neuron Diseases ◽  
African Populations ◽  
Sub Saharan

Motor neuron diseases (MNDs) are devastating neurological diseases that are characterised by gradual degeneration and death of motor neurons. Major types of MNDs include amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). These diseases are incurable, with limited disease-modifying treatment options. In order to improve MND-based biomedical research, drug development, and clinical care, population-based studies will be important. These studies, especially among less-studied populations, might identify novel factors controlling disease susceptibility and resistance. To evaluate progress in MND research in Africa, we examined the published literature on MNDs in Sub-Saharan Africa to identify disease prevalence, genetic factors, and other risk factors. Our findings indicate that the amount of research evidence on MNDs in Sub-Saharan Africa is scanty; molecular and genetics-based studies are particularly lacking. While only a few genetic studies were identified, these studies strongly suggest that there appear to be population-specific causes of MNDs among Africans. MND genetic underpinnings vary among different African populations and also between African and non-African populations. Further studies, especially molecular, genetic and genomic studies, will be required to advance our understanding of MND biology among African populations. Insights from these studies would help to improve the timeliness and accuracy of clinical diagnosis and treatment.

French coopération in the field of education (1960–1980): a story of disillusionment

2013 ◽  
pp. 120-134 ◽  
Author(s):  
Samy Mesli
Keyword(s):  
Early Years ◽  
Sub Saharan Africa ◽  
Cultural Dimension ◽  
African Continent ◽  
Francophone Africa ◽  
Fifth Republic ◽  
Secondary Sector ◽  
African Populations ◽  
Sub Saharan ◽  
Physical Construction

Sami Mesly investigates the cultural dimension of continuities between France and various states of ‘Francophone Africa’, as expressed through the co-operation agreements between the independent governments and the French state under the Fifth Republic. These latter guaranteed, initially, a steady exchange between the partners in the field of education. As France’s former colonial territories in sub-Saharan Africa were suddenly confronted with a greatly reduced public budget, French financial help was crucial, in the early years after independence, both for the physical construction of a school infrastructure and for the deployment of thousands of coopérants who became an important part of the staff in African schools. As late as the early 1980s, this French presence remained very significant. It spanned the whole of school education, including the primary and secondary sector, technical education, and higher education (French funding was instrumental in the creation of African universities). Mesly points out that while it is obvious that the French effort has made a major contribution to the growth of the education sector on the African continent, French aid in education offers nevertheless an ambivalent picture. The programmes implemented were poorly adapted to local realities, which in the end led to the installation of a system conditioned by the French view of African populations and not by local needs.

scholarly journals Disease burden and the role of pharmacogenomics in African populations

2017 ◽  
Vol 2 ◽  
Author(s):  
K. L. Mpye ◽  
A. Matimba ◽  
K. Dzobo ◽  
S. Chirikure ◽  
A. Wonkam ◽  
...  
Keyword(s):  
Disease Burden ◽  
Individual Variability ◽  
Sub Saharan Africa ◽  
Drug Side Effects ◽  
Quality Healthcare ◽  
Therapeutic Drugs ◽  
African Populations ◽  
The Status ◽  
Sub Saharan

Background.The burden of communicable and non-communicable diseases in Sub-Saharan Africa poses a challenge in achieving quality healthcare. Although therapeutic drugs have generally improved health, their efficacy differs from individual to individual. Variability in treatment response is mainly because of genetic variants that affect the pharmacokinetics and pharmacodynamics of drugs.Method.The intersection of disease burden and therapeutic intervention is reviewed, and the status of pharmacogenomics knowledge in African populations is explored.Results.The most commonly studied variants with pharmacogenomics relevance are discussed, especially in genes coding for enzymes that affect the response to drugs used for HIV, malaria, sickle cell disease and cardiovascular diseases.Conclusions.The genetically diverse African population is likely to benefit from a pharmacogenomics-based healthcare approach, especially with respect to reduction of drug side effects, and separation of responders and non-responders leading to optimized drug choices and doses for each patient.

scholarly journals Single nucleotide polymorphism induces divergent dynamic patterns in CYP3A5: a microsecond scale biomolecular simulation of variants identified in Sub-Saharan African populations

2021 ◽  
Author(s):  
Houcemeddine Othman ◽  
Jorge Emanuel Batista da Rocha ◽  
Scott Hazelhurst
Keyword(s):  
Structural Changes ◽  
Rare Variants ◽  
Drug Binding ◽  
Sub Saharan Africa ◽  
High Coverage ◽  
Single Nucleotide ◽  
African Populations ◽  
Sub Saharan ◽  
Dynamics Simulations ◽  
The Impact

Pharmacogenomics aims to reveal variants associated with drug response phenotypes. Genes whose roles involve the absorption, distribution, metabolism, and excretion of drugs, are highly polymorphic between populations. High coverage whole genome sequencing showed that a large proportion of the variants for these genes are rare in African populations. This study investigates the impact of such variants on protein structure to assess their functional importance. We use genetic data of CYP3A5 from 458 individuals from sub-Saharan Africa to conduct a structural bioinformatics analysis. Five missense variants were modeled and microsecond scale molecular dynamics simulations were conducted for each, as well as for the CYP3A5 wildtype, and the Y53C variant, which has a known deleterious impact on enzyme activity. The binding of ritonavir and artemether to CYP3A5 variant structures was also evaluated. Our results showed different conformational characteristics between all the variants. No significant structural changes were noticed. However, the genetic variability acts on the plasticity of the protein. The impact on drug binding may be drug dependant. We conclude that rare variants hold relevance in determining the pharmacogenomics properties of populations. This could have a significant impact on precision medicine applications in sub-Saharan Africa.

scholarly journals Globalization and Public Health in Rural Zones: Lessons from Sub-Saharan Africa

2021 ◽  
Vol 2 (Fall/Winter) ◽  
pp. 1-14
Author(s):  
Benjamin Poku ◽  
Jean-Leopold Kabambi
Keyword(s):  
Public Health ◽  
Rural Communities ◽  
Economic Benefits ◽  
Sub Saharan Africa ◽  
Rural Regions ◽  
Community Based ◽  
African Populations ◽  
Negative Effect ◽  
Sub Saharan

Distant rural regions of Sub-Saharan Africa are often coveted by foreign investing companies for their natural resources. However, the rural populations do not always take advantage of the economic benefits resulting from those investing activities. These increasing activities do not leave without harming the health of rural communities as they rely on community-based traditional and ancestral practices such as fishing and hunting, traditional medicine, spiritual ceremonies, among others, to survive. We aimed to analyze selected indicators of public health in rural zones highly impacted by globalization factors using existing database and literature research. Given the complexity of the situation, efforts and strategies to mitigate the negative effect of globalization on the health of rural communities must include not only urgent and binding commitment of all stakeholders but also a multi-sectorial long-term approach to increase the health of rural Sub-Saharan African populations while taking advantages of local know-how.

Facial human bites. Vision on STMMs in Africa

2020 ◽  
Vol 74 (2) ◽  
pp. 1-5
Author(s):  
Pedro Clarós ◽  
Natalia Końska ◽  
Andrés Clarós
Keyword(s):  
Sub Saharan Africa ◽  
Medical Documentation ◽  
Appearance Management ◽  
Human Bites ◽  
African Populations ◽  
The Face ◽  
History Of ◽  
Free Grafts ◽  
Sub Saharan ◽  
Age Range

ABSTRACT Objectives: Human bites of the face are a frequent and serious health issue as they often compromise patients function and aesthetics as well as lead to further complications. The aim of the study is to review human bites of the face referred to our team during 112 short-term medical missions (STMMs) in Sub-Saharan Africa over the past 20 years and to discuss the epidemiology, appearance, management and outcome, including the most common complications. Methods: A retrospective medical documentation review was carried out examining all human bites of the face operated by our team during 112 STMMs from 2000 to 2019 in different countries of Sub-Saharan Africa. Results: Out of about 5500 patients medical charts 51 patients were selected due to history of human bite. Patients’ age range was 15-65 years, female to male ratio was 1, 55:1, the most often involved parts were: lips, ear and nose. Various surgical procedures were carried out including local flaps and free grafts. Infection and graft necrosis were the most common reported complication (n=4, 9,3 %). Conclusion: Human bites injuries are a serious health problem in some African populations because of their frequency and possible severity. The treatment is particularly challenging due to their potential to cause local infections, the risk they pose for transmission of systemic diseases as well as their demanding surgical management.

Common and Founder Mutations for Monogenic Traits in Sub-Saharan African Populations

2018 ◽  
Vol 19 (1) ◽  
pp. 149-175
Author(s):  
Amanda Krause ◽  
Heather Seymour ◽  
Michèle Ramsay
Keyword(s):  
Molecular Genetic ◽  
Black Families ◽  
Oculocutaneous Albinism ◽  
Sub Saharan Africa ◽  
Founder Mutations ◽  
Monogenic Diseases ◽  
African Populations ◽  
Clinical Consequences ◽  
Sub Saharan ◽  
Almost All

This review highlights molecular genetic studies of monogenic traits where common pathogenic mutations occur in black families from sub-Saharan Africa. Examples of founder mutations have been identified for oculocutaneous albinism, cystic fibrosis, Fanconi anemia, and Gaucher disease. Although there are few studies from Africa, some of the mutations traverse populations across the continent, and they are almost all different from the common mutations observed in non-African populations. Myotonic dystrophy is curiously absent among Africans, and nonsyndromic deafness does not arise from mutations in GJB2 and GJB7. Locus heterogeneity is present for Huntington disease, with two common triplet expansion loci in Africa, HTT and JPH3. These findings have important clinical consequences for diagnosis, treatment, and genetic counseling in affected families. We currently have just a glimpse of the molecular etiology of monogenic diseases in sub-Saharan Africa, a proverbial “ears of the hippo” situation.

scholarly journals Beta-globin gene haplotypes and selected Malaria-associated variants among black Southern African populations

2017 ◽  
Vol 2 ◽  
Author(s):  
G. D. Pule ◽  
E. R. Chimusa ◽  
K. Mnika ◽  
K. Mhandire ◽  
E. Kampira ◽  
...  
Keyword(s):  
Positive Selection ◽  
Sickle Cell ◽  
Evolutionary Dynamics ◽  
Globin Gene ◽  
Sub Saharan Africa ◽  
Migration Route ◽  
Beta Globin ◽  
African Populations ◽  
Sub Saharan ◽  
Selection Of

Partial carrier-resistance toPlasmodium falciparummalaria conferred by the sickle cell (HbS) mutation has resulted in the local amplification and positive selection of sickle cell disease (SCD) in malaria-endemic regions and particularly in sub-Saharan Africa (SSA). The present study investigated theβ-globin gene haplotypes, and selected malaria-associated variants among three cohorts of Bantu-speaking individuals from Malawi, Zimbabwe and South Africa compared with reports with data from others SSA populations. The data suggest a south-ward frequency decrease of malaria-associated variants in SSA linked to the evolutionary dynamics of various African populations’ genomes through selective pressure of malaria. These selected genomics differences, positive selection of SCD in malaria-endemic regions among ‘Bantus’ from various part of Africa emphasise the evidence of the dissociation between genetics, anthropology and culture. The present study also showed a relatively prevalent Benin haplotype, which is mostly found in West Africa, among Southern African Blacks and very low Bantu haplotype, which could suggest a major migration route, of Southern Africa Bantu, along the African west coast, post-occurrence of the Sickle cell mutation, which date remain to be fully elucidated.

scholarly journals Urinary schistosomosis in patients of rural medical health centers in Kwale county, Kenya

2020 ◽  
Vol 57 (1) ◽  
pp. 19-27 ◽  
Author(s):  
A. Kaiglová ◽  
M. J. S. Changoma ◽  
J. Špajdelová ◽  
D. Jakubcová ◽  
K. Bírová
Keyword(s):  
Low Income ◽  
Genetic Material ◽  
Public Health Problem ◽  
Health Care Facilities ◽  
Sub Saharan Africa ◽  
Intermediate Hosts ◽  
Filtration Method ◽  
Sub Saharan ◽  
Local Water ◽  
Study Participants

SummaryUrinary schistosomosis is a serious public health problem prevalent in low-income rural regions of sub-Saharan Africa, including coastal part of Kenya. Praziquantel administration to school-aged children is the prevailing tool of schistosomosis control in these regions. The aim of our study was to find out if this control strategy can lead to interruption of parasite trasmission and disease elimination. During February and March 2018, the occurrence of urinary schistosomosis in volunteers of primary health care facilities in Kwale County, Kenya was examined and the occurrence of infected intermediate hosts Bulinus globosus in local water resources was monitored. Participants completed a questionnaire concerning source of water for household purposes, type of housing and health status and were asked to provide urine samples. Diagnosis of urinary schistosomosis was established by detection of Schistosoma haematobium eggs in urine specimens microscopically, using filtration method. Infected B. globosus snails were detected using cercaria shedding tests. From the hemolymph of snails, prepatent period of infection was identified by polymerase chain reaction (PCR). The presence of urinary schistosomosis was detected in 15.07 % (69 out of 451) of study participants. Cercaria shedding test was positive in 2 particular sites of river Pengo and Tsanganyiko. Genetic material (haemolymph) of 68 B. globosus snails tested by DraI PCR revealed 7 Schistosoma spp. positive samples. Six of seven DraI positive snails were infected by S. haematobium, as it was detected by Sh110/SmS1 PCR. The study revealed, that the disease was still present in the region studied and the transmission was not interrupted. The rate of infection was significantly influenced by the water supplies used for household purposes and the type of housing.

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