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BACKGROUND AND OBJECTIVES: Recessive inheritance of African-specific APOL1 kidney risk variants is associated with higher risk of nondiabetic kidney disease, progression to kidney failure, and early-onset albuminuria that precedes eGFR decline. The effect of APOL1 risk variants on kidney disease in continental Africans is understudied. Objectives of this study were to determine APOL1 risk allele prevalence and associations between APOL1 genotypes and kidney disease in West, East, and South Africa. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This cross-sectional population-based study in four African countries included 10,769 participants largely aged 40–60 years with sociodemographic and health information, anthropometry data, and blood and urine tests for biomarkers of kidney disease. APOL1 risk alleles were imputed from the H3Africa genotyping array, APOL1 risk allele and genotype frequencies were determined, and genetic associations were assessed for kidney disease. Kidney disease was defined as the presence of eGFR

Most hypertension-related genome-wide association studies (GWAS) focus on non-African populations, despite hypertension (a major risk factor for cardiovascular disease) being highly prevalent in Africa. The AWI-Gen study GWAS meta-analysis for blood pressure-related traits (systolic and diastolic blood pressure, pulse pressure, mean-arterial pressure and hypertension) from three sub-Saharan African geographic regions (N=10,775), identified two genome-wide significant signals (p

MotivationGenome-wide association studies (GWASs) analyse genetic variation over the genomes of many individuals in an attempt to identify single nucleotide polymorphisms (SNPs) associated with complex phenotypes. To capture a large amount of genetic variation and increase the chance of detecting associated SNPs, modern GWASs include millions of SNPs sampled from thousands of individuals. The cumulative probability of false associations increases with the number of SNPs included in the analysis. A GWAS, therefore, needs to control the number of false associations. Permutation testing is a straightforward and accurate method of controlling the false positive rate, but it is very computationally expensive (and slow) so there is a need for a permutation testing accelerator that can process modern GWAS datasets in reasonable time.ResultsFPGAs (Field-Programmable Gate Arrays) are reconfigurable integrated circuits which provide a high level of parallelisation that can be harnessed to accelerate GWAS permutation testing. This work presents an accessible FPGA-based tool (designed to run on a cloud-based AWS EC2 FPGA instance) that accelerates GWAS permutation testing for continuous phenotypes. The tool implements two known GWAS permutation testing algorithms: maxT permutation testing and adaptive permutation testing. The speed of the FPGA-based tool was compared to the speed of PLINK (a popular CPU-based tool) running on 40 Intel Xeon 4114 CPU cores using an imputed breast cancer dataset of 13.7 million SNPs sampled from 3652 individuals. For 1000 maxT permutations, the FPGA-based algorithm’s run time was 22 minutes while PLINK’s run time was almost 7 days; for 100 million adaptive permutations, the FPGA-based algorithm’s run time was 325 minutes and PLINK’s run time was about 8.5 days. For 700 million adaptive permutations of the same dataset (an almost unfeasible workload for PLINK running on a 40-core CPU) the run time of the FPGA-accelerated algorithm was 33 hours.AvailabilityAn EC2 AMI (FPGA_perm) in the us-east-1 region is available. Instructions, source code and sample data are available at https://github.com/witseie/fpgaperm.

Breast cancer (BC) is the most common cancer among African women and is the second most common cause of cancer deaths in Africa as estimated by GLOBOCAN 2018.1 Cancer incidence is increasing in Africa1 and is associated largely with lifestyle changes, resulting from increased urbanization.2 Ferlay et al3 predicted a 49% increase in BC incidence across Africa between 2018 and 2040, an increase faster than any other region in the world. The International Association of Cancer Registries cancer incidence report includes data for only 20 of 46 sub-Saharan African (SSA) countries,4 and it is likely that the incidence of BC is under-reported owing to lack of infrastructure for cancer diagnosis in resource-constrained countries in SSA.5 Also, owing to the large burden of communicable and other noncommunicable diseases in SSA, most resources are directed at controlling these diseases.6,7 Cancer research, especially molecular research, in SSA is often deprioritized against other pressing public health concerns.8 CONTEXT Key Objective Both rare and common genetic variants contribute to the risk of breast cancer (BC). Much is known about the genetics of BC in populations of European origin. Our objective was to review studies of genetic susceptibility to BC in the populations of sub-Saharan Africa to identify knowledge gaps and propose study designs to address these. Knowledge Generated A total of 22 studies were identified in 10 of 46 countries in sub-Saharan Africa. Rare variants predicted to be pathogenic were detected most commonly in the BRCA1, BRCA2, and PALB2 genes. There were few studies of common genetic variants, none of which provided strong evidence for association with BC risk. Relevance Knowledge of genetic factors contributing to BC risk has important implications for patients and their families both for genetic counseling and for potential access to new therapies, which improve survival and reduce side effects.

Genome-wide association studies (GWAS) provide huge information on statistically significant single-nucleotide polymorphisms (SNPs) associated with various human complex traits and diseases. By performing GWAS studies, scientists have successfully identified the association of hundreds of thousands to millions of SNPs to a single phenotype. Moreover, the association of some SNPs with rare diseases has been intensively tested. However, classic GWAS studies have not yet provided solid, knowledgeable insight into functional and biological mechanisms underlying phenotypes or mechanisms of diseases. Therefore, several post-GWAS (pGWAS) methods have been recommended. Currently, there is no simple scientific document to provide a quick guide for performing pGWAS analysis. pGWAS is a crucial step for a better understanding of the biological machinery beyond the SNPs. Here, we provide an overview to performing pGWAS analysis and demonstrate the challenges behind each method. Furthermore, we direct readers to key articles for each pGWAS method and present the overall issues in pGWAS analysis. Finally, we include a custom pGWAS pipeline to guide new users when performing their research.

Genetic associations for lipid traits have identified hundreds of variants with clear differences across European, Asian and African studies. Based on a sub-Saharan-African GWAS for lipid traits in the population cross-sectional AWI-Gen cohort (N = 10,603) we report a novel LDL-C association in the GATB region (P-value=1.56 × 10

To identify pathogenic variants in a cohort of 23 black South African children with sporadic primary congenital glaucoma (PCG) using an exome-based approach.Children with PCG were recruited from two Paediatric Ophthalmology Clinics in Johannesburg, South Africa. Whole exome sequencing was performed on genomic DNA. Of the 23 children, 19 were male and 19 had bilateral PCG. A variant prioritization strategy was employed whereby variants in known PCG genes (CYP1B1, LTBP2 and TEK) were evaluated first, followed by the identification of putative disease-causing variants in other genes related to eye diseases and phenotypes.Validated pathogenic variants in the CYP1B1 gene (c.1169 GA; p.Arg390His) and TEK gene (c.922 GA; p.Gly308Arg) were identified in one child each. No LTBP2 mutations were identified in this cohort. In silico predictions identified potentially damaging rare variants in genes previously associated with eye development phenotypes or glaucoma in a further 12 children.This study demonstrates the value of whole exome sequencing in identifying disease-causing variants in African children with PCG. It is the first report of a TEK disease-causing variant in an African PCG patient. Potential causative variants detected in PCG candidate genes warrant further investigation.

Globally, chronic kidney disease (CKD) contributes substantial morbidity and mortality. Recently, various ‘omics platforms have provided insight into the molecular basis of kidney dysfunction. This scoping review is a synthesis of the current literature on the use of different ‘omics platforms to identify biomarkers that could be used to detect early-stage CKD, predict disease progression, and identify pathways leading to CKD. This review includes 123 articles published from January 2007 to May 2021, following a structured selection process. The most common type of ‘omic platform was proteomics, appearing in 55 of the studies and two of these included a metabolomics component. Most studies (n = 91) reported on CKD associated with diabetes mellitus. Thirteen studies that provided information on the biomarkers associated with CKD and explored potential pathways involved in CKD are discussed. The biomarkers that are associated with risk or early detection of CKD are SNPs in the MYH9/APOL1 and UMOD genes, the proteomic CKD273 biomarker panel and metabolite pantothenic acid. Pantothenic acid and the CKD273 biomarker panel were also involved in predicting CKD progression. Retinoic acid pathway genes, UMOD, and pantothenic acid provided insight into potential pathways leading to CKD. The biomarkers were mainly used to detect CKD and predict progression in high-income, European ancestry populations, highlighting the need for representative ‘omics research in other populations with disparate socio-economic strata, including Africans, since disease etiologies may differ across ethnic groups. To assess the transferability of findings, it is essential to do research in diverse populations.

Atherosclerosis precedes the onset of many clinical manifestations of cardiovascular diseases (CVDs). We used carotid intima-media thickness (cIMT) to investigate genetic susceptibility to atherosclerosis in 7894 unrelated adults (3963 women, 3931 men) aged 40 to 60 years resident in four sub-Saharan African countries. cIMT was measured by ultrasound and genotyping was performed on the H3Africa SNP Array. Two new African-specific genome-wide significant loci, SIRPA (p=4.7E-08), and FBXL17 (p=2.5E-08), were identified in the combined dataset. Sex-stratified analysis revealed associations with two male-specific loci, SNX29 (p=6.3E-09) and MAP3K7 (p=5.3E-08), and two female-specific loci, LARP6 (p=2.4E-09) and PROK1 (p=1.0E-08). Regional associations were replicated with known risk loci for atherosclerosis and CVDs with different lead SNPs than in Europeans and significant enrichment for oestrogen response genes for female-specific signals were identified. The genes identified showed biological relevance to atherosclerosis and/or CVDs, as well as sex-differences and transferability of signals from non-African studies.

Atherosclerosis precedes the onset of clinical manifestations of cardiovascular diseases (CVDs). We used carotid intima-media thickness (cIMT) to investigate genetic susceptibility to atherosclerosis in 7894 unrelated adults (3963 women, 3931 men; 40 to 60 years) resident in four sub-Saharan African countries. cIMT was measured by ultrasound and genotyping was performed on the H3Africa SNP Array. Two new African-specific genome-wide significant loci for mean-max cIMT, SIRPA (p = 4.7E-08), and FBXL17 (p = 2.5E-08), were identified. Sex-stratified analysis revealed associations with one male-specific locus, SNX29 (p = 6.3E-09), and two female-specific loci, LARP6 (p = 2.4E-09) and PROK1 (p = 1.0E-08). We replicate previous cIMT associations with different lead SNPs in linkage disequilibrium with SNPs primarily identified in European populations. Our study find significant enrichment for genes involved in oestrogen response from female-specific signals. The genes identified show biological relevance to atherosclerosis and/or CVDs, sex-differences and transferability of signals from non-African studies.

Chloroquine/hydroxychloroquine have been proposed as potential treatments for COVID-19. These drugs have warning labels for use in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Analysis of whole genome sequence data of 458 individuals from sub-Saharan Africa showed significant G6PD variation across the continent. We identified nine variants, of which four are potentially deleterious to G6PD function, and one (rs1050828) that is known to cause G6PD deficiency. We supplemented data for the rs1050828 variant with genotype array data from over 11,000 Africans. Although this variant is common in Africans overall, large allele frequency differences exist between sub-populations. African sub-populations in the same country can show significant differences in allele frequency (e.g. 16.0% in Tsonga vs 0.8% in Xhosa, both in South Africa, p = 2.4 × 10−3). The high prevalence of variants in the G6PD gene found in this analysis suggests that it may be a significant interaction factor in clinical trials of chloroquine and hydroxychloroquine for treatment of COVID-19 in Africans.

Chloroquine/hydroxychloroquine have been proposed as potential treatments for COVID-19. These drugs have warning labels for use in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Analysis of whole-genome sequence data of 458 individuals from sub-Saharan Africa showed significant G6PD variation across the continent. We identified nine variants, of which four are potentially deleterious to G6PD function, and one (rs1050828) that is known to cause G6PD deficiency. We supplemented data for the rs1050828 variant with genotype array data from over 11,000 Africans. Although this variant is common in Africans overall, large allele frequency differences exist between sub-populations. African sub-populations in the same country can show significant differences in allele frequency (e.g. 16.0% in Tsonga vs 0.8% in Xhosa, both in South Africa, p = 2.4 × 10−3). The high prevalence of variants in the G6PD gene found in this analysis suggests that it may be a significant interaction factor in clinical trials of chloroquine and hydrochloroquine for treatment of COVID-19 in Africans.

The spread of COVID-19 caused by the SARS-CoV-2 outbreak has been growing since its first identification in December 2019. The publishing of the first SARS-CoV-2 genome made a valuable source of data to study the details about its phylogeny, evolution, and interaction with the host. Protein-protein binding assays have confirmed that Angiotensin-converting enzyme 2 (ACE2) is more likely to be the cell receptor through which the virus invades the host cell. In the present work, we provide an insight into the interaction of the viral spike Receptor Binding Domain (RBD) from different coronavirus isolates with host ACE2 protein. By calculating the binding energy score between RBD and ACE2, we highlighted the putative jump in the affinity from a progenitor form of SARS-CoV-2 to the current virus responsible for COVID-19 outbreak. Our result was consistent with previously reported phylogenetic analysis and corroborates the opinion that the interface segment of the spike protein RBD might be acquired by SARS-CoV-2 via a complex evolutionary process rather than a progressive accumulation of mutations. We also highlighted the relevance of Q493 and P499 amino acid residues of SARS-CoV-2 RBD for binding to human ACE2 and maintaining the stability of the interface. Moreover, we show from the structural analysis that it is unlikely for the interface residues to be the result of genetic engineering. Finally, we studied the impact of eight different variants located at the interaction surface of ACE2, on the complex formation with SARS-CoV-2 RBD. We found that none of them is likely to disrupt the interaction with the viral RBD of SARS-CoV-2., Highlights • We noticed a large difference in the binding energy of RBD from the spike protein of SARS-CoV-2 with ACE2, compared to the closest isolates to the proposed progenitor forms. • Currently, available sequence data do not explain the transition from low-affinity RBD forms to high-affinity RBD that are capable to infect the Humans. • We suggest that residues N493Q and not N501T as was reported previously is responsible for a higher affinity toward ACE2 when we compare SARS-CoV-2 to SARS-CoV. • The mutation T499P is responsible for stabilizing the interface of RBD interacting with ACE2 when we compare SARS-CoV-2 to SARS-CoV. • It is unlikely that the interface of RBD from SARS-CoV-2 is a result of human intervention aiming to increase the affinity toward ACE2. • The role of receptors other than ACE2 is shown, and these may have a more critical function in crossing the species barrier. • Variants that corresponding to residues on the ACE2 interface are unlikely to be associated with resistance or sensibility forms compared to the reference allele.

Esophageal squamous cell carcinoma (ESCC) has a high incidence in sub-Saharan Africa and a poor prognosis, but little is known about the genetic contribution to ESCC susceptibility in this region. We carried out a GWAS in the South African Black (SAB) population with 1,686 ESCC cases and 3,217 controls as part of the Evolving Risk Factors for Cancer in African populations (ERICA-SA) study after ethical approval and informed consent. ESCC case samples from ERICA-SA and controls from the H3A AWI-Gen study were genotyped on the 2.3 million H3 Africa SNP Illumina array and additional SNPs imputed using the Wellcome Sanger Institute imputation service. Measures for correction of population structure included Eigen decomposition for Principal Component (PC) analysis. The final imputed dataset of 14.4M SNPs for 1,686 OSCC cases and 3,217 population controls was used in linear-mixed model analysis to test for association using GEMMA. A meta-analysis of SNP sets common to both our study and a GWAS of 2,013 Chinese ESCC cases and 2,701 controls was done using METAL. The GWAS of the SAB population identified a total of 62 SNPs with suggestive association with ESCC (P < 5x10-6), from 29 independent potential risk loci. A strong signal at genome-wide significance is located upstream of the FAM120A gene on chromosome 9 (rs1237966, p=4.58x10-8) and is supported by multiple SNPs at this locus. FAM120A encodes an RNA binding protein which is a critical component of oxidative stress-induced signalling. A strong association was also observed on chromosome 2, led by rs142741123 (p=5.49x10-8) in a region spanning the MYO1B and STAT4 genes with SNPs that are absent in non-African populations, suggesting that this is an African-specific risk locus for ESCC. There was limited support for the association of ESCC risk loci reported in other populations in our study. We did a meta-analysis of the SAB GWAS with a published GWAS of Chinese ESSC cases and controls with 4.85 million SNPs shared between the two studies. A total of 12 SNPs were associated with ESCC at genome-wide significance. These included 3 loci: chromosome 9, led by rs12379660 (p-valuemeta = 9.36x10-10), chromosome 10 led by rs7099485 (p-valuemeta = 1.48x10-8) and chromosome 22 led by rs1033667 (p-valuemeta = 1.47x10-9). The chromosome 9 locus at FAM120A is the novel locus identified in our African ESCC GWAS, the chromosome 10 locus at PLCE1 shows association only in the Chinese GWAS, and the chromosome 22 locus at CHEK2 was previously identified in the Chinese ESCC GWAS, and is supported further by the African ESCC GWAS. This study is, to our knowledge, the first cancer GWAS conducted in solely in a resident African population, and has detected two novel risk loci for ESCC at or near genome-wide significance, one of which is likely specific to African populations. It also demonstrates the power of trans-ethnic meta-analysis to identify common or distinct risk loci in populations of diverse ancestry. Citation Format: Wenlong C. Chen, Jean-Tristan Brandenburg, Ananyo Choudhury, Mahtaab Hayat, Dhriti Sengupta, Chantal Babb de Villiers, Lucien Ferndale, Cassandra Soo, Sang H. Lee, Charles Curtis, Robert Newton, Tim Waterboer, Frederic Sitas, Michele Ramsay, Christian C. Abnet, Colleen Aldous, Mohamed I. Parker, Elvira Singh, Deborah Bradshaw, Cathryn M. Lewis, Christopher G. Mathew. Genome-wide association study of African esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 31.

Despite Nb and Ta being considered as ‘geochemical twins’, most Ta mineral deposits are associated with muscovite-bearing peraluminous granites and related pegmatites (MPG), whereas significant Nb deposits are related to peralkaline to metaluminous A1-type granites and syenites as well as nepheline syenites. Metaluminous to peraluminous A2-type granites and syenites have a lower potential for rare-metal mineralization. The Nb/Ta ratios are highly variable within each type of rare-metal-enriched felsic igneous suite and causes of the Nb-Ta geochemical fractionation remain poorly understood. Our compilation of whole-rock geochemical data indicates that Nb/Ta ratios generally anticorrelate with Ta, and at given Ta contents the Nb/Ta ratios increase from MPG through A2-type to A1-type igneous suites. However, the Nb-Ta compositions of A1-type and silica-undersaturated felsic magmatic rocks are indistinguishable. New regression models to estimate the mineral/melt partition coefficients DNb and DTa indicate that fractional crystallization of biotite and ilmenite significantly decreases Nb/Ta, but an extreme degree of fractional crystallization is needed to explain the observed range of Nb-Ta variations in rare-metal-enriched igneous suites. Importantly, metasomatic rocks formed by the alteration of igneous suites and their country-rocks are commonly highly enriched in Ta and Nb. Their low Nb/Ta ratios suggest that magmatic-hydrothermal processes involving fluids and hydrosaline melts also play a critical role in Nb-Ta geochemical fractionation and HFSE enrichment in general. We show that the Nb-Ta compositions of the primitive end-members of rare-metal-enriched felsic igneous suites fingerprint the nature and evolution of their sources including metasomatic processes in the Earth's crust and upper mantle.

Objective: The extent to which social organization of human societies impacts the patterns of genetic diversity remains an open question. Here, we investigate the transmission of reproductive success in patrilineal and cognatic populations from Central Asia using a coalescent approach. Methods: We performed a study on the mitochondrial DNA (mtDNA) and Y chromosome polymorphism of patrilineal and cognatic populations from Central Asia. We reconstructed the gene genealogies in each population for both kind of markers and inferred the imbalance level of these genealogies, a parameter directly related to the level of transmission of reproductive success. Results: This imbalance level appeared much stronger for the Y chromosome in patrilineal populations than in cognatic populations, while no difference was found for mtDNA. Furthermore, we showed that this imbalance level correlates negatively with Y-chromosomal, mtDNA, and autosomal genetic diversity. Conclusions: This shows that patrilineality might be one of the factors explaining the male transmission of reproductive success, which, in turn, lead to a reduction of genetic diversity. Thus, notwithstanding the fact that our population genetic approach clearly shows that there is a strong male-biased transmission of reproductive success in patrilineal societies, it also highlights the fact that a social process such as cultural transmission of reproductive success could play an important role in shaping human genetic diversity, although we cannot formally exclude that this transmission has also a genetic component. Am J Phys Anthropol 157:537–543, 2015. © 2015 Wiley Periodicals, Inc.

International audience; Gene presence–absence polymorphisms segregating within species are a significant source of genetic variation but have been little investigated to date in natural populations. In plant pathogens, the gain or loss of genes encoding proteins interacting directly with the host, such as secreted proteins, probably plays an important role in coevolution and local adaptation. We investigated gene presence–absence polymorphism in populations of two closely related species of castrating anther-smut fungi, Microbotryum lychnidis-dioicae (MvSl) and M. silenes-dioicae (MvSd), from across Europe, on the basis of Illumina genome sequencing data and high-quality genome references. We observed presence–absence polymorphism for 186 autosomal genes (2% of all genes) in MvSl, and only 51 autosomal genes in MvSd. Distinct genes displayed presence–absence polymorphism in the two species. Genes displaying presence–absence polymorphism were frequently located in subtelomeric and centromeric regions and close to repetitive elements, and comparison with outgroups indicated that most were present in a single species, being recently acquired through duplications in multiple-gene families. Gene presence–absence polymorphism in MvSl showed a phylogeographic structure corresponding to clusters detected based on SNPs. In addition, gene absence alleles were rare within species and skewed toward low-frequency variants. These findings are consistent with a deleterious or neutral effect for most gene presence–absence polymorphism. Some of the observed gene loss and gain events may however be adaptive, as suggested by the putative functions of the corresponding encoded proteins (e.g., secreted proteins) or their localization within previously identified selective sweeps. The adaptive roles in plant and anther-smut fungi interactions of candidate genes however need to be experimentally tested in future studies.

SummaryFertility transmission (FT) is a phenomenon with a cultural and/or genetic basis, whereby a positive correlation exists between the number of offspring of an individual and that of his/her parents. Theoretical studies using a haploid individual-based model have shown that FT increases the variance and intergenerational correlation in reproductive success and results in an imbalance in the coalescent tree of sampled genes. This phenomenon has been documented in several demographic studies conducted on the correlation in fertility between generations, or through the reconstruction of the genealogical trees of mitochondrial DNA sequences. However, as mtDNA is a single locus, potentially subject to other forces (e.g. natural selection), it is of interest to extend the theory of FT to nuclear loci. We show that because random mating between individuals leads to a mixing of their fertility profiles, FT in these cases will have less influence on the variance and intergenerational correlation of reproductive success. This, in turn, results in less impact on the shape of the coalescent trees. Nevertheless, in the presence of FT, high heterogeneity in reproductive success and homogamy for family size will increase the imbalance in the coalescent tree. Thus, FT should be easier to detect when occurring in conjunction with these other factors. We also show the utility of analysing different kinds of loci (X-linked, Y-linked, mitochondrial and autosomal) to assess whether FT is matrilineal, patrilineal or biparental. Finally, we demonstrate that the shape of the coalescent tree depends upon population size, in contrast to the classical Kingman's model.

Complex phenotypes are often controlled by many interacting genes. One question emerging from such organization is how selection, acting at the phenotypic level, shapes the evolution of genes involved in regulatory networks controlling the phenotypes. We studied this issue through a matrix model of such networks. In a population submitted to selection, we simulated the evolution of a quantitative trait controlled by a set of loci that regulate each other through positive or negative interactions. Investigating several levels of selection intensity on the trait, we studied the evolution of regulation intensity between the genes and the evolution of the genetic diversity of those genes as an indirect measure of the strength of selection acting on them. We show that an increasing intensity of selection on the phenotype leads to an increased level of regulation between the loci. Moreover, we found that the genes responding more strongly to selection within the network were those evolving towards stronger regulatory action on the other genes and/or those that are the less regulated by the other genes. This observation is strongest for an intermediate level of selection. This may explain why several experimental studies have shown evidence of selection on regulatory genes inside gene networks.