Genome-wide structure of West Cape Coloured population (de Wit et al. 2010)

On the left Figure S5: Proportion of each individual’s ancestry derived using the linkage model in STRUCTURE for the optimal number of ancestral populations (K = 4) (TIFF 102 kb)

Related:

• Genetic ancestry of Coloured South Africans
• Origin of South African Couloured population

Human Genetics doi:10.1007/s00439-010-0836-1

Genome-wide analysis of the structure of the South African Coloured Population in the Western Cape

Erika de Wit et al.

Admixed populations present unique opportunities to discover the genetic factors underlying many multifactorial diseases. The geographical position and complex history of South Africa has led to the establishment of the unique admixed population known as the South African Coloured. Not much is known about the genetic make-up of this population, and the historical record is patchy. We genotyped 959 individuals from the Western Cape area, self-identified as belonging to this population, using the Affymetrix 500k genotyping platform. This resulted in nearly 75,000 autosomal SNPs that could be compared with populations represented in the International HapMap Project and the Human Genome Diversity Project. Analysis by means of both the admixture and linkage models in STRUCTURE revealed that the major ancestral components of this population are predominantly Khoesan (32–43%), Bantu-speaking Africans (20–36%), European (21–28%) and a smaller Asian contribution (9–11%), depending on the model used. This is consistent with historical data. While of great historical and genealogical interest, this information is also essential for future admixture mapping of disease genes in this population.

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Origin of South African Couloured population

Photo from Wikipedia article.

AJHG doi:10.1016/j.ajhg.2010.02.014

Strong Maternal Khoisan Contribution to the South African Coloured Population: A Case of Gender-Biased Admixture

Lluis Quintana-Murci et al.

Abstract

The study of recently admixed populations provides unique tools for understanding recent population dynamics, socio-cultural factors associated with the founding of emerging populations, and the genetic basis of disease by means of admixture mapping. Historical records and recent autosomal data indicate that the South African Coloured population forms a unique highly admixed population, resulting from the encounter of different peoples from Africa, Europe, and Asia. However, little is known about the mode by which this admixed population was recently founded. Here we show, through detailed phylogeographic analyses of mitochondrial DNA and Y-chromosome variation in a large sample of South African Coloured individuals, that this population derives from at least five different parental populations (Khoisan, Bantus, Europeans, Indians, and Southeast Asians), who have differently contributed to the foundation of the South African Coloured. In addition, our analyses reveal extraordinarily unbalanced gender-specific contributions of the various population genetic components, the most striking being the massive maternal contribution of Khoisan peoples (more than 60%) and the almost negligible maternal contribution of Europeans with respect to their paternal counterparts. The overall picture of gender-biased admixture depicted in this study indicates that the modern South African Coloured population results mainly from the early encounter of European and African males with autochthonous Khoisan females of the Cape of Good Hope around 350 years ago.

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Genetic ancestry of Coloured South Africans

Hum Mol Genet. 2009

Genetic structure of a unique admixed population: implications for medical research.

Patterson N, Petersen DC, van der Ross RE, Sudoyo H, Glashoff RH, Marzuki S, Reich D, Hayes VM.

Understanding human genetic structure has fundamental implications for understanding the evolution and impact of human diseases. In this study we describe the complex genetic substructure of a unique and recently admixed population arising approximately 350 years ago as a direct result of European settlement in South Africa. Analysis was performed using over 900,000 genome-wide single nucleotide polymorphisms in 20 unrelated ancestry-informative marker selected Coloured individuals and made comparisons with historically predicted founder populations. We show that there is substantial genetic contribution from at least four distinct population groups: Europeans, South Asians, Indonesians, and a population genetically close to the isiXhosa sub-Saharan Bantu. This is in good accord with the historical record. We briefly examine the implications of determining the genetic diversity of this population, not only for furthering understanding of human evolution out of Africa, but also for genome-wide association studies using admixture mapping. In conclusion, we define the genetic structure of a uniquely admixed population that holds great potential to advance genetic-based medical research.

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