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:Transcription profiling of permethrin resistant field mosquito samples of Anopheles funestus from three Southern African populations (Mozambique, Malawi and Zambia) compared to a susceptible lab strain FANG
Project description:<p>The goal of this study was to identify genes and loci associated with pigmentation in African populations. It comprises 1,593 participants from Ethiopia, Tanzania, and Botswana. Sexes are evenly represented (768 males and 825 females) and self reported ages ranged from 18 to 103. Mean age was used for individuals without ages. For each participant, a DSM II color meter was used to measure underarm skin reflectance in triplicate. These measures averaged and converted to a melanin index (MI = 100 x log10(1/(x/255)). All individuals were included in a genome wide scan that accounted for age, sex, and genetic relatedness.</p>
Project description:Skin color is highly variable in Africans, yet little is known about the underlying molecular mechanism. We identified 1,157 candidate variants influencing skin pigmentation in indigenous Africans by genome-wide association studies and scans of natural selection based on differentiation in allele frequencies between lightly pigmented southern African Khoesan populations and other darkly pigmented African populations. We applied massively parallel reporter and chromosome conformation capture assays to identify novel regulatory variants and their target genes related to skin pigmentation in melanocytic cells. We identified 165 SNPs showing strong differential regulatory activities between alleles. Combining CRISPR-mediated genome editing, transcriptome profiling and melanin assays, we identified causal regulatory variants impacting pigmentation near MFSD12/HMG20B, MITF, OCA2, and DDB1/CYB561A3/TMEM138. We identified CYB561A3 as a novel gene regulating pigmentation by impacting genes involved in oxidative phosphorylation and melanogenesis. Our results broaden our understanding of the genetic basis of human skin color diversity and human adaptation. To test the role of candidate enhancers and variants in skin pigmentation, we performed CRISPR inhibition or knockout of enhancers containing the functional variants identified by MPRA in melanocytic cells. Then, we performed gene expression profiling analysis using data obtained from RNA-seq of these CRISPR-edited cells. We also performed RNA-seq using CYB561A3-koncout MNT1 cells or CYB561A3-overexpressing MNT1 cells
Project description:Skin color is highly variable in Africans, yet little is known about the underlying molecular mechanism. We identified 1,157 candidate variants influencing skin pigmentation in indigenous Africans by genome-wide association studies and scans of natural selection based on differentiation in allele frequencies between lightly pigmented southern African Khoesan populations and other darkly pigmented African populations. We applied massively parallel reporter and chromosome conformation capture assays to identify novel regulatory variants and their target genes related to skin pigmentation in melanocytic cells. We identified 165 SNPs showing strong differential regulatory activities between alleles. Combining CRISPR-mediated genome editing, transcriptome profiling and melanin assays, we identified causal regulatory variants impacting pigmentation near MFSD12/HMG20B, MITF, OCA2, and DDB1/CYB561A3/TMEM138. We identified CYB561A3 as a novel gene regulating pigmentation by impacting genes involved in oxidative phosphorylation and melanogenesis. Our results broaden our understanding of the genetic basis of human skin color diversity and human adaptation. To decipher the target genes of the MFVs, we performed Hi-C and H3K27ac HiChIP assays in MNT1 cells. Hi-C is a high-throughput method for detecting chromatin interactions at whole genome scale and is often used to identify topologically associating domains (TADs) in the nucleus. H3K27ac HiChIP can identify chromatin interactions enriched for H3K27ac, a histone modification associated with active promoters and enhancers. We performed bridge linker mediated Hi-C and H3K27ac HiChIP using double (Hae3_Alu1) as well as single (Hae3) enzyme digestion in MNT-1 cells.