Project description:The genetic structure of the indigenous hunter-gatherer peoples of Southern Africa, the oldest known lineage of modern man, holds an important key to understanding humanity's early history. Previously sequenced human genomes have been limited to recently diverged populations. Here we present the first complete genome sequences of an indigenous hunter-gatherer from the Kalahari Desert and of a Bantu from Southern Africa, as well as protein-coding regions from an additional three hunter-gatherers from disparate regions of the Kalahari. We characterize the extent of whole-genome and exome diversity among the five men, reporting 1.3 million novel DNA differences genome-wide, and 13,146 novel amino-acid variants. These data allow genetic relationships among Southern African foragers and neighboring agriculturalists to be traced more accurately than was previously possible. Adding the described variants to current databases will facilitate inclusion of Southern Africans in medical research efforts.
Project description:The genetic structure of the indigenous hunter-gatherer peoples of Southern Africa, the oldest known lineage of modern man, holds an important key to understanding humanity's early history. Previously sequenced human genomes have been limited to recently diverged populations. Here we present the first complete genome sequences of an indigenous hunter-gatherer from the Kalahari Desert and of a Bantu from Southern Africa, as well as protein-coding regions from an additional three hunter-gatherers from disparate regions of the Kalahari. We characterize the extent of whole-genome and exome diversity among the five men, reporting 1.3 million novel DNA differences genome-wide, and 13,146 novel amino-acid variants. These data allow genetic relationships among Southern African foragers and neighboring agriculturalists to be traced more accurately than was previously possible. Adding the described variants to current databases will facilitate inclusion of Southern Africans in medical research efforts. Copy number differences between NA18507 and KB1 were predicted from the depth of whole-genome shotgun sequence reads. These predictions were then validated using array-CGH using a a genome-wide design as well as a custom design targeted at specific regions of copy number difference
Project description:Cowpea (Vigna unguiculata) is an important protein source in Sub-Saharan Africa. Optimizing resilience and productivity through genetic engineering in cowpea has been slow due in part to a lack of defined species-specific regulatory elements and difficulty testing gene function within the native system. In many plant species, Agrobacterium-mediated transient gene expression is widely used to validate constructs before investing in transgenic lines, but its implementation in legumes has been challenging. In this study, we optimized an in planta agroinfiltration assay in trifoliate cowpea leaves using a betalain reporter. To demonstrate the “intact plant” aspect of this system, we used this assay to characterize drought-inducible promoters by challenging cowpea plants with drought stress. Subsequently, to identify and broaden the pool of native promoters known in cowpea, we developed a user-friendly web application, CowPEAsy, allowing users to interrogate gene expression from our canopy-level, developmental-series RNA-Seq dataset. Finally, using CowPEAsy, we identified six promoters that showed constitutive expression across all conditions and verified these promoters with our transient system. This work provides an in vivo platform for preliminary validation of regulatory elements in cowpea and other legumes and enhances current genetic resources by identifying a suite of physiologically relevant promoters of varying strengths.
Project description:The history of click-speaking Khoe-San, and African populations in general, remains poorly understood. We genotyped ~2.3 million SNPs in 220 southern Africans and found that the Khoe-San diverged from other populations at least 100,000 years ago, but structure within the Khoe-San dated back to about 35,000 years ago. Genetic variation in various sub-Saharan populations did not localize the origin of modern humans to a single geographic region within Africa, instead, it indicated a history of admixture and stratification. We found evidence of adaptation targeting muscle function and immune response, potential adaptive introgression of UV-light protection, and selection predating modern human diversification involving skeletal and neurological development. These new findings illustrate the importance of African genomic diversity in understanding human evolutionary history .220 samples were analysed with the Illumina HumanOmni2.5-Quad BeadChip and are described herein.
Project description:Background: Cowpea (Vigna unguiculata L. Walp) is an important food and fodder legume of the semiarid tropics and subtropics worldwide, especially in sub-Saharan Africa. High density genetic linkage maps are needed for marker assisted breeding but are not available for cowpea. A single feature polymorphism (SFP) is a microarray-based marker which can be used for high throughput genotyping and high density mapping. Results: Here we report detection and validation of SFPs in cowpea using a readily available soybean (Glycine max) genome array. Robustified projection pursuit (RPP) was used for statistical analysis using RNA as a surrogate for DNA. Using a 15% outlying score cut-off, 1058 potential SFPs were enumerated between two parents of a recombinant inbred line (RIL) population segregating for several important traits including drought tolerance, Fusarium and brown blotch resistance, grain size and photoperiod sensitivity. Sequencing of 25 putative polymorphism-containing amplicons yielded a SFP probe set validation rate of 68%. Conclusions: We conclude that the Affymetrix soybean genome array is a satisfactory platform for identification of some 1000's of SFPs for cowpea. This study provides an example of extension of genomic resources from a well supported species to an orphan crop. Presumably, other legume systems are similarly tractable to SFP marker development using existing legume array resources. Keywords: Polymorphism discovery, array based genotyping
Project description:Genetic, linguistic, and archaeological studies have demonstrated the existence of strong links between eastern and southern Africa over the past millennia, including the diffusion of the first domesticated sheep and goats. However, the proportions at which they were introduced into past human subsistence strategies in Africa is difficult to assess archaeologically, as caprines share skeletal features with a number of wild bovids. Palaeoproteomics has proven effective at retrieving biological information from archaeological remains in African arid contexts. Using published collagen sequences and generated de novo ones of wild bovids, we present the molecular (re-)attribution of remains morphologically identified as sheep/goat or unidentifiable bovids from seventeen archaeological sites distributed between eastern and southern Africa and spanning seven millennia. More than 70% of the remains were identified and the direct radiocarbon dating of domesticates specimens allowed the chronological refinement of the arrival of caprines in both African regions. Our results further substantiate a predominance of sheep in the assemblages along with a similar arrival chronology. Beyond adding substantial biological data to the field of (palaeo-)proteomics, it is the first large-scale palaeoproteomics investigation to include both eastern and southern African sites, opening promising future applications of the method on the continent.
Project description:The main objective of the project is to find the reason why antivenoms commonly used in treatments of Naja mossambica bites are not effective in Eswatini and Mozambique, whereas they exhibit normal activity in other countries of southern Africa. The main hypothesis here assumes that intra-species differences in protein composition of venoms from different part of the continent are the main cause of observed diversity in antivenom efficacy. In the course of the project, there is also a plan to identify the specific toxins that differ analyzed venoms in reactivity towards antivenom immunoglobulins.
Project description:The main objective of the project is to find the reason why antivenoms commonly used in treatments of Naja mossambica bites are not effective in Eswatini and Mozambique, whereas they exhibit normal activity in other countries of southern Africa. The main hypothesis here assumes that intra-species differences in protein composition of venoms from different part of the continent are the main cause of observed diversity in antivenom efficacy. In the course of the project, there is also a plan to identify the specific toxins that differ analyzed venoms in reactivity towards antivenom immunoglobulins.
Project description:The hunter-gatherers and pastoralists of South Africa retain the highest genetic diversity of any population. Genetic determinants of light skin pigmentation, reduced stature etc and other basic biomedical phenotypes are unique to samples with Southern African hunter-gatherer and pastoralist ancestry or retain ancestral haplotypes not found in other populations.