It has been 100 years since the first report of sickle haemoglobin (HbS). More than 50 years ago, it was suggested that the gene responsible for this disorder could reach high frequencies because of resistance conferred against malaria by the heterozygous carrier state. This traditional example of balancing selection is known as the 'malaria hypothesis'. However, the geographical relationship between the transmission intensity of malaria and associated HbS burden has never been formally investigated on a global scale. Here, we use a comprehensive data assembly of HbS allele frequencies to generate the first evidence-based map of the worldwide distribution of the gene in a Bayesian geostatistical framework. We compare this map with the pre-intervention distribution of malaria endemicity, using a novel geostatistical area-mean comparison. We find geographical support for the malaria hypothesis globally; the relationship is relatively strong in Africa but cannot be resolved in the Americas or in Asia.

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Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis

In this study, we investigated the relationship between pain and pancreatic pressure in patients with chronic pancreatitis (CP). We studied 12 patients with CP undergoing surgery and five controls with cancer of the pancreatic tail. CP was staged on the basis of morphological (ERP) and functional (serum-pancreolauryl test) criteria. Patients kept daily records of the intensity of pain on a linear analog scale. Intraoperatively, pressure within the pancreas was assessed by the introduction of a fine needle into the pancreatic parenchyma connected to a pressure transducer. In controls, pressure was determined in macroscopically normal tissue in the head of the pancreas. Pancreatic pressure was significantly higher in CP than in controls (29.9 ± 3.1 vs 7.2 ± 1.1 mmHg, p < 0.001). No relationship was found between the pain score and the pancreatic pressure. Pressure was positively correlated with ductal changes (r = 0.831;p<0.001), but not with exocrine function of the pancreas. Postoperatively, pancreatic pressure fell by 15.3% in four patients with CP in whom pressure assessment was repeated after surgical decompression. We conclude that pancreatic parenchy pressure is not closely related to pain in CP.

Is increased pancreatic pressure related to pain in chronic pancreatitis

Although marriages between close biological kin are preferential in many parts of the world, there still is a remarkable lack of knowledge of this central feature of human kinship structure, in particular how consanguinity might influence reproductive behavior, and consanguinity-associated morbidity and mortality. The principal aim of this report is to provide a detailed and comprehensive review of the current global prevalence of consanguineous marriages. The review is based almost exclusively on data collated from refereed journal articles, supplemented where appropriate by information from edited book chapters, papers submitted for publication and personal communications. All of the results cited refer either to the current parental generation or to the two immediate past parental generations.

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Empirical estimates of the global prevalence of consanguineous marriage in contemporary societies

926 women attending the Obstetrics and Gynaecology Department of the Faculty of Medicine, Khartoum, were investigated to study the inbreeding effects on reproductive profiles and morbidity of the offspring. 49.5% of the women had married their first cousins and 13.8% had married more distant relatives. Altogether, 4,471 pregnancy outcomes were analysed including abortions, still births, neonatal and childhood deaths, physical deformity, mental retardation and other congenital abnormalities. No significant difference in the reproductive loss or net fertility was observed between the inbred and outbred groups. Only the proportions of childhood deaths were found to be significantly higher in the inbred marriages (p less than 0.005). The morbidity was also not affected by the practice of inbreeding.

Inbreeding Effects on Reproductive Outcome in a Sudanese Population

Northeast Africa has a long history of human habitation, with fossil-finds from the earliest anatomically modern humans, and housing ancient civilizations. The region is also the gate-way out of Africa, as well as a portal for migration into Africa from Eurasia via the Middle East and the Arabian Peninsula. We investigate the population history of northeast Africa by genotyping ~3.9 million SNPs in 221 individuals from 18 populations sampled in Sudan and South Sudan and combine this data with published genome-wide data from surrounding areas. We find a strong genetic divide between the populations from the northeastern parts of the region (Nubians, central Arab populations, and the Beja) and populations towards the west and south (Nilotes, Darfur and Kordofan populations). This differentiation is mainly caused by a large Eurasian ancestry component of the northeast populations likely driven by migration of Middle Eastern groups followed by admixture that affected the local populations in a north-to-south succession of events. Genetic evidence points to an early admixture event in the Nubians, concurrent with historical contact between North Sudanese and Arab groups. We estimate the admixture in current-day Sudanese Arab populations to about 700 years ago, coinciding with the fall of Dongola in 1315/1316 AD, a wave of admixture that reached the Darfurian/Kordofanian populations some 400-200 years ago. In contrast to the northeastern populations, the current-day Nilotic populations from the south of the region display little or no admixture from Eurasian groups indicating long-term isolation and population continuity in these areas of northeast Africa.

/pdf/northeast-african-genomic-variation-shaped-by-the-continuity-16p1abkcbt.pdf

Northeast African genomic variation shaped by the continuity of indigenous groups and Eurasian migrations

The average inbreeding coefficients of the highly consanguineous Fur and Baggara tribes of Western Sudan were 004167 and 004450, respectively Two hundred ninety-eight subjects from the two tribes were tested for polymorphism of hemoglobins, seven red cell enzymes, and four serum proteins The Baggara showed a higher gene frequency of HbS and TfD and lower gene frequency of GdA and PC compared to the Fur Both tribes showed a low gene frequency of PGM1 and high frequency of G6PD deficiency when compared to other Sudanese tribes In spite of the high degree of inbreeding, no significant deviation from the Hardy-Weinburg equilibrium was observed in either tribe The effects of inbreeding seem to be offset by mixing between the two tribes on Gabal Marra Plateau The flow of the sickle gene from the Baggara into the Fur and other Sudanese tribes is discussed

A study of some genetic characteristics of the Fur and Baggara tribes of the Sudan

The overall prevalence rate of endemic goitre among the Fur and Baggara tribes of Western Sudan was found to be 74%. Family studies in 60 nuclear families showed a significantly higher incidence of en

T. S. M. Taha

Papers

A study of some genetic characteristics of the Fur and Baggara tribes of the Sudan

Study of possible genetic predisposition to endemic goitre among the Fur and Baggara tribes of the Sudan.