West African Ethnic Groups Research Articles

Male Circumcision and the Epidemic Emergence of HIV-2 in West Africa.

BackgroundEpidemic HIV-2 (groups A and B) emerged in humans circa 1930–40. Its closest ancestors are SIVsmm infecting sooty mangabeys from southwestern Côte d'Ivoire. The earliest large-scale serological surveys of HIV-2 in West Africa (1985–91) show a patchy spread. Côte d'Ivoire and Guinea-Bissau had the highest prevalence rates by then, and phylogeographical analysis suggests they were the earliest epicenters. Wars and parenteral transmission have been hypothesized to have promoted HIV-2 spread. Male circumcision (MC) is known to correlate negatively with HIV-1 prevalence in Africa, but studies examining this issue for HIV-2 are lacking.MethodsWe reviewed published HIV-2 serosurveys for 30 cities of all West African countries and obtained credible estimates of real prevalence through Bayesian estimation. We estimated past MC rates of 218 West African ethnic groups, based on ethnographic literature and fieldwork. We collected demographic tables specifying the ethnic partition in cities. Uncertainty was incorporated by defining plausible ranges of parameters (e.g. timing of introduction, proportion circumcised). We generated 1,000 sets of past MC rates per city using Latin Hypercube Sampling with different parameter combinations, and explored the correlation between HIV-2 prevalence and estimated MC rate (both logit-transformed) in the 1,000 replicates.Results and ConclusionsOur survey reveals that, in the early 20th century, MC was far less common and geographically more variable than nowadays. HIV-2 prevalence in 1985–91 and MC rates in 1950 were negatively correlated (Spearman rho = -0.546, IQR: -0.553–-0.546, p≤0.0021). Guinea-Bissau and Côte d'Ivoire cities had markedly lower MC rates. In addition, MC was uncommon in rural southwestern Côte d'Ivoire in 1930.The differential HIV-2 spread in West Africa correlates with different historical MC rates. We suggest HIV-2 only formed early substantial foci in cities with substantial uncircumcised populations. Lack of MC in rural areas exposed to bushmeat may have had a role in successful HIV-2 emergence.

Bentyia (Kukyia): a Songhay–Mande meeting point, and a “missing link” in the archaeology of the West African diasporas of traders, warriors, praise-singers, and clerics

The present tragedy in Mali draws our attention to the divisions, tensions and conflicts between West African ethnic groups, religious persuasions, and populations from different regions, in both the present and the past. But a long-term critical perspective on the past brings to light borrowings between cultures, and shows how the mobility of people across West Africa links regional and ethnic histories. The communication axis running from the Aḍagh to the Niger and, along the Niger Valley, from Gao to Busa (in Nigerian Borgu) and beyond, is a strategic locus for investigating this mobility and connectivity. It has linked together the Saharan, savannah, and forest zones of West Africa. It was a magnet for diasporas of Soninke praise-singers and Mande warriors and traders. Fishermen and other waterfolk along the river, oral traditionists and other craftspeople, priests and priestesses of African cults, and Islamic clerics, as well as armies, long-distance merchants, and enslaved human beings, moved along it. Although the archeological sites at Bentyia/Kukyia occupy a strategic position on this historical axis, they have not been excavated, whence a serious gap in our knowledge of the history of the eastern Niger Valley and of West Africa as a whole.

English

Several craniometric studies involving Caucasian, Mongoloid and Americans have been conducted and its usefulness in facilitating proper identification of skeletal remains and in emphasizing a common origin of studied populations cannot be overemphasized. This study involved 699 (male 361; female 338) volunteer students of Delta State University whose age ranged 18 years and over. Respondents were selected along three ethnic groups including Urhobo (male 156; female 147), Ibo (male 141; female 145) and Edo (male 64; female 46). The mean cephalic index (CI) between the sampled populations was 77.95 ± 4.34 cm. There was an observed significant effect of age on cephalic index (p < 0.01) but gender showed no significant effects on cephalic index. The values for the three selected tribes did not differ significantly from one another nor differ from the population mean (p < 0.05). The mean male and female CI values were 77.67 and 78.14 cm, respectively. The Cephalic index patterns of three indigenous West African ethnic groups (Urhobo, Edo and Ibo) was presented in this study highlighting certain features common to West African and perhaps African populations. It was shown that Cephalic index were significant indices for differentiation of population groups and cultures. In spite of these observations, differences which enable intracultural differentiation commonly occur as exhibited by the craniometric pattern in this study. Inevitably therefore, craniometric studies are most essential in the study of population dynamics especially with respect to quantitative variables.   Key words: Cephalic, mesocephalic, gender, culture, West Africa.

Patterns of cephalic indexes in three West African populations

Several craniometric studies involving Caucasian, Mongoloid and Americans have been conducted and its usefulness in facilitating proper identification of skeletal remains and in emphasizing a common origin of studied populations cannot be overemphasized. This study involved 699 (male 361; female 338) volunteer students of Delta State University whose age ranged 18 years and over. Respondents were selected along three ethnic groups including Urhobo (male 156; female 147), Ibo (male 141; female 145) and Edo (male 64; female 46). The mean cephalic index (CI) between the sampled populations was 77.95 ± 4.34 cm. There was an observed significant effect of age on cephalic index (p < 0.01) but gender showed no significant effects on cephalic index. The values for the three selected tribes did not differ significantly from one another nor differ from the population mean (p < 0.05). The mean male and female CI values were 77.67 and 78.14 cm, respectively. The Cephalic index patterns of three indigenous West African ethnic groups (Urhobo, Edo and Ibo) was presented in this study highlighting certain features common to West African and perhaps African populations. It was shown that Cephalic index were significant indices for differentiation of population groups and cultures. In spite of these observations, differences which enable intracultural differentiation commonly occur as exhibited by the craniometric pattern in this study. Inevitably therefore, craniometric studies are most essential in the study of population dynamics especially with respect to quantitative variables.

HLA-DRB1 and -DQB1 loci in three west African ethnic groups: Genetic relationship with sub-Saharan African and European populations

The Fulani of west Africa have been shown to be less susceptible to malaria and to mount a stronger immune response to malaria than sympatric ethnic groups. The analysis of HLA diversity is useful for the assessment of the genetic distance between the Fulani and sympatric populations, which represents the necessary theoretical background for the investigation of genetic determinants of susceptibility to malaria. We assessed the polymorphism of HLA-DRB1 and - DQB1 loci and analyzed the distribution of alleles/haplotypes in Fulani, Mossi, and Rimaibé from Burkina Faso. We then investigated the genetic relationship of these three ethnic groups with other sub-Saharan African populations as well as with Europeans. We confirmed that the Fulani from Burkina Faso are genetically distinct from sympatric Mossi and Rimaibé. Furthermore the Fulani from Burkina Faso are close to those from The Gambia and, intriguingly, share the distribution of specific alleles with east African populations (Amhara and Oromo). It is noteworthy that the HLA-DRB1*04 and - DQB1*02 alleles, which are implicated in the development of several autoimmune diseases, are present at high frequency in the Fulani, suggesting their potential involvement in the enhanced immune reactivity observed in this population.

Interferon regulatory factor-1 polymorphisms are associated with the control of Plasmodium falciparum infection

We describe the haplotypic structure of the interferon regulatory factor-1 (IRF-1) locus in two West African ethnic groups, Fulani and Mossi, that differ in their susceptibility and immune response to Plasmodium falciparum malaria. Both populations showed significant associations between IRF-1 polymorphisms and carriage of P. falciparum infection, with different patterns of association that may reflect their different haplotypic architecture. Genetic variation at this locus does not therefore account for the Fulani-specific resistance to malaria while it could contribute to parasite clearance's ability in populations living in endemic areas. We then conducted a case-control study of three haplotype-tagging single nucleotide polymorphisms (htSNPs) in 370 hospitalised malaria patients (160 severe and 210 uncomplicated) and 410 healthy population controls, all from the Mossi ethnic group. All three htSNPs showed correlation with blood infection levels in malaria patients, and the rs10065633 polymorphism was associated with severe disease (P=0.02). These findings provide the first evidence of the involvement in malaria susceptibility of a specific locus within the 5q31 region, previously shown to be linked with P. falciparum infection levels.

African-American mitochondrial DNAs often match mtDNAs found in multiple African ethnic groups

BackgroundMitochondrial DNA (mtDNA) haplotypes have become popular tools for tracing maternal ancestry, and several companies offer this service to the general public. Numerous studies have demonstrated that human mtDNA haplotypes can be used with confidence to identify the continent where the haplotype originated. Ideally, mtDNA haplotypes could also be used to identify a particular country or ethnic group from which the maternal ancestor emanated. However, the geographic distribution of mtDNA haplotypes is greatly influenced by the movement of both individuals and population groups. Consequently, common mtDNA haplotypes are shared among multiple ethnic groups. We have studied the distribution of mtDNA haplotypes among West African ethnic groups to determine how often mtDNA haplotypes can be used to reconnect Americans of African descent to a country or ethnic group of a maternal African ancestor. The nucleotide sequence of the mtDNA hypervariable segment I (HVS-I) usually provides sufficient information to assign a particular mtDNA to the proper haplogroup, and it contains most of the variation that is available to distinguish a particular mtDNA haplotype from closely related haplotypes. In this study, samples of general African-American and specific Gullah/Geechee HVS-I haplotypes were compared with two databases of HVS-I haplotypes from sub-Saharan Africa, and the incidence of perfect matches recorded for each sample.ResultsWhen two independent African-American samples were analyzed, more than half of the sampled HVS-I mtDNA haplotypes exactly matched common haplotypes that were shared among multiple African ethnic groups. Another 40% did not match any sequence in the database, and fewer than 10% were an exact match to a sequence from a single African ethnic group. Differences in the regional distribution of haplotypes were observed in the African database, and the African-American haplotypes were more likely to match haplotypes found in ethnic groups from West or West Central Africa than those found in eastern or southern Africa. Fewer than 14% of the African-American mtDNA sequences matched sequences from only West Africa or only West Central Africa.ConclusionOur database of sub-Saharan mtDNA sequences includes the most common haplotypes that are shared among ethnic groups from multiple regions of Africa. These common haplotypes have been found in half of all sub-Saharan Africans. More than 60% of the remaining haplotypes differ from the common haplotypes at a single nucleotide position in the HVS-I region, and they are likely to occur at varying frequencies within sub-Saharan Africa. However, the finding that 40% of the African-American mtDNAs analyzed had no match in the database indicates that only a small fraction of the total number of African haplotypes has been identified. In addition, the finding that fewer than 10% of African-American mtDNAs matched mtDNA sequences from a single African region suggests that few African Americans might be able to trace their mtDNA lineages to a particular region of Africa, and even fewer will be able to trace their mtDNA to a single ethnic group. However, no firm conclusions should be made until a much larger database is available. It is clear, however, that when identical mtDNA haplotypes are shared among many ethnic groups from different parts of Africa, it is impossible to determine which single ethnic group was the source of a particular maternal ancestor based on the mtDNA sequence.

Mitochondrial DNA genetic diversity among four ethnic groups in Sierra Leone

Although there are numerous ethnic groups in Sierra Leone, the Mende and Temne together account for approximately 60% of the total population. To see if genetic differences could be observed among ethnic groups in Sierra Leone, the nucleotide sequence of the hypervariable 1 (HV1) region of mitochondrial DNA (mtDNA) was determined from samples of the two major ethnic groups, the Mende (n=59) and Temne (n=121), and of two minor ethnic groups, the Loko (n=29) and Limba (n=67). Among these 276 HV1 sequences, 164 individual haplotypes were observed. An analysis of molecular variance indicated that the distribution of these haplotypes within the Limba sample was significantly different from that of the other ethnic groups. No significant genetic variation was seen between the Mende, Temne, and Loko. These results indicate that distinguishing genetic differences can be observed among ethnic groups residing in historically close proximity to one another. Furthermore, we observed some mitochondrial DNA haplotypes that are common among the Sierra Leone ethnic groups but that have not been observed in other published studies of West African ethnic groups. Therefore, we may have evidence for mtDNA lineages that are unique to this region of West Africa.

Genetic structure in four West African population groups

BackgroundAfrica contains the most genetically divergent group of continental populations and several studies have reported that African populations show a high degree of population stratification. In this regard, it is important to investigate the potential for population genetic structure or stratification in genetic epidemiology studies involving multiple African populations. The presences of genetic sub-structure, if not properly accounted for, have been reported to lead to spurious association between a putative risk allele and a disease. Within the context of the Africa America Diabetes Mellitus (AADM) Study (a genetic epidemiologic study of type 2 diabetes mellitus in West Africa), we have investigated population structure or stratification in four ethnic groups in two countries (Akan and Gaa-Adangbe from Ghana, Yoruba and Igbo from Nigeria) using data from 372 autosomal microsatellite loci typed in 493 unrelated persons (986 chromosomes).ResultsThere was no significant population genetic structure in the overall sample. The smallest probability is associated with an inferred cluster of 1 and little of the posterior probability is associated with a higher number of inferred clusters. The distribution of members of the sample to inferred clusters is consistent with this finding; roughly the same proportion of individuals from each group is assigned to each cluster with little variation between the ethnic groups. Analysis of molecular variance (AMOVA) showed that the between-population component of genetic variance is less than 0.1% in contrast to 99.91% for the within population component. Pair-wise genetic distances between the four ethnic groups were also very similar. Nonetheless, the small between-population genetic variance was sufficient to distinguish the two Ghanaian groups from the two Nigerian groups.ConclusionThere was little evidence for significant population substructure in the four major West African ethnic groups represented in the AADM study sample. Ethnicity apparently did not introduce differential allele frequencies that may affect analysis and interpretation of linkage and association studies. These findings, although not entirely surprising given the geographical proximity of these groups, provide important insights into the genetic relationships between the ethnic groups studied and confirm previous results that showed close genetic relationship between most studied West African groups.

Black Rice: The African Origins of Rice Cultivation in the Americas

Black Rice: The African Origins of Rice Cultivation in the Americas

HLA class I in three West African ethnic groups: genetic distances from sub-Saharan and Caucasoid populations.

Fulani of Burkina Faso (West Africa) are a particularly interesting ethnic group because of their lower susceptibility to Plasmodium falciparum malaria as compared to sympatric populations, Mossi and Rimaibé. Moreover, the occurrence of a Caucasoid component in their genetic make-up has been suggested on the basis of their physical traits and cultural traditions even though this view was not supported by genetic studies. A total of 149 unrelated subjects (53 Mossi, 47 Rimaibé and 49 Fulani) have been typed for 97 HLA class I alleles with the amplification refractory mutation system/polymerase chain reaction (ARMS/PCR) technique. Mossi and Rimaibé data were pooled since none of the 42 statistically testable alleles exhibited a significant heterogeneity. These pooled gene frequencies were found to be very different from those of Fulani: a certain (P<0.001) or a likely (0.001 <P<0.01) difference was found for 5 and 12 alleles, respectively. Four alleles (A*24, A*29, B*27, B*3701) appeared to be essentially "private" Fulani alleles with respect to the other two populations but their presence was not associated with higher resistance to P. falciparum. Our data have then been compared using chord distances (CD) with those from the literature on Africans (including Gambian Fulani) and Caucasoids. The Burkina Faso and Gambian Fulani turned out to be very different (CD=2.191). Moreover, Burkina Faso Fulani were very distant from sympatric Mossi and Rimaibé (CDs=1.912 and 1.884), whereas Gambian Fulani were similar to sympatric Mandinka and Wolof (CDs=0.412 and 0.388) to an extent comparable to that found between Mossi and Rimaibé (CD=0.555). Our study does not suggest the involvement of HLA I in the higher resistance to malaria of Fulani, and confirms a low, if any, Caucasoid component in their gene pool.

Interethnic differences in the humoral response to non-repetitive regions of the Plasmodium falciparum circumsporozoite protein.

We analyzed the humoral immune response to the amino- (amino acids 22-125) and carboxy-terminal (amino acids 289-390) non-repetitive domains of the Plasmodium falciparum circumsporozoite protein (PfCSP) in individuals belonging to three west African ethnic groups (the Fulani, Mossi, and Rimaibé) living in the same conditions of hyperendemic transmission in a Sudan savanna area of Burkina Faso. Previous surveys conducted in the same area showed obvious interethnic differences in the susceptibility and immune reactivity to malaria, with the Fulani showing lower infection and disease rates and higher humoral responses to various P. falciparum antigens than sympatric ethnic groups. A total of 764 subjects (311 Mossi, 273 Rimaibé, and 180 Fulani) of all age classes were tested. The total mean +/- SE anti-(CSPf-N-term) and anti-(CSPf-C-term) seroprevalences were 65.6 +/- 1.7% and 57.0 +/- 1.8%, respectively. These seroprevalences were lower than that recorded in the same sample for the central (NANP)40 repetitive domain (88.3 +/- 1.2%). As previously reported for other P. falciparum antigens (PfCSP-(NANP)40, thrombospondin-related anonymous protein, merozoite surface protein-1, Pf155-ring-infected erythrocyte surface antigen, and Pf332), in spite of similar exposure to malaria, the Fulani showed higher immune reactivity than sympatric populations for both antigens tested. Our results confirm the presence of B cell epitopes in the non-repetitive regions of the PfCSP; moreover a further evidence of interethnic differences in the capacity to mount humoral responses against P. falciparum malaria was obtained. The assessment of the biological basis of interethnic heterogeneities in the susceptibility and in the humoral immune responses to malaria appears relevant in the development of anti-malaria vaccines.

O259 - HLA class I and class II alleles in three sympatric West African ethnic groups

O259 - HLA class I and class II alleles in three sympatric West African ethnic groups

The coevolutionary relationship of humans and domesticated plants

Human-plant interactions have figured prominently in our species' evolution and they continue to influence the contemporary geographical patterns of human biodiversity. The domestication of particular plant taxa has genetically modified those taxa and intensified human contact with specific plants and their endogenous bioactive allelochemicals (secondary plant compounds). This contact, sustained over multiple generations of humans and plants has provided, on occasion, unique opportunities for amplified interactions of microevolutionary importance. In this paper, a theoretical overview of these interactions is presented and four case studies are detailed as examples of local potentially coevolutionary specificity. The first set of case studies include two human-plant diads: 1) salivary proline-rich proteins and carcinoma in East Asian ethnic groups and ingestion of tea (Camellia sinensis) flavonoids (polyphenols) and 2) HLADQ2+ phenotypes and celiac disease in Northern Atlantic European ethnic groups and ingestion of wheat (Triticum aestivum) A-gliadin peptides. Since established human-plant interactions frequently involve a third species, the second set of case studies includes two human-plant-parasite triads: 1) red blood cell G6PD variants similar to Gdmed and favism in Mediterranean ethnic groups and ingestion of fava bean (Vicia faba) glycosides and exposure to Plasmodium falciparum malaria and 2) HbβS phenotypes and sickle cell anemia in West African ethnic groups and ingestion of cassava (Manihot esculenta) cyanogenic glucosides and exposure to Plasmodium falciparum malaria. © 1996 Wiley-Liss, Inc.

西アフリカ諸民族の生体計測調査 (その1)

西アフリカ諸民族の生体計測調査 (その1)

HLA-DRB, -DQA and -DQB gene polymorphisms in four West African ethnic groups

HLA-DRB, -DQA and -DQB gene polymorphisms in four West African ethnic groups

Guinea yams the botany, ethnobotany, use and possible future of yams in West Africa

Of all the food crop plants of the tropics, few are as closely associated with a particular group of people, or particular cultural area, as are yams with certain of the West African peoples. Yams are grown and used in many other parts of the tropics, but in few other areas of the world are they so central a feature of day-to-day life. African cultural patterns tend to be strongly oriented towards staple carbohydrate foods in the food/agricultural complex (Uchendu, 1970), and through much of West Africa the yam is still a prominent factor in the cultural life, as well as the material subsistence of the population. In much of West Africa, yams are still the preferred staple food among most of the inhabitants of the forest zone and of the southern parts of the savannah. It may be no coincidence that the highest cultures of forest zone in West Africa Ashanti, Brong Ahafo, Ife, Igbo Ukwu and Beninarose in areas where yam was the staple food. Before the widespread impact of Western European ideologies and education during the present century, rituals associated with events in the yam farming calendar were major cultural junctures in the year among most West African ethnic groups and the yam harvest was regarded as the equivalent of the New Year. The paramount position of the yams has been diminished by in-