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 a highly heritable human trait, and global variation in skin pigmentation has been shaped by natural selection, migration and admixture. Ethnically diverse African populations harbor extremely high levels of genetic and phenotypic diversity, and skin pigmentation varies widely across Africa. Recent genome-wide genetic studies of skin pigmentation in African populations have advanced our understanding of pigmentation biology and human evolutionary history. For example, novel roles in skin pigmentation for loci near MFSD12 and DDB1 have recently been identified in African populations. However, due to an underrepresentation of Africans in human genetic studies, there is still much to learn about the evolutionary genetics of skin pigmentation. Here, we summarize recent progress in skin pigmentation genetics in Africans and discuss the importance of including more ethnically diverse African populations in future genetic studies. In addition, we discuss methods for functional validation of adaptive variants related to skin pigmentation.
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