Abstract:
BACKGROUND : The Afrikaner population of South Africa is the descendants of European colonists who started to
colonize the Cape of Good Hope in the 1600s. In the early days of the colony, mixed unions between European
males and non-European females gave rise to admixed children who later became incorporated into either the
Afrikaner or the Coloured populations of South Africa. Differences in ancestry, social class, culture, sex ratio and
geographic structure led to distinct and characteristic admixture patterns in the Afrikaner and Coloured
populations. The Afrikaner population has a predominant European composition, whereas the Coloured population
has more diverse ancestries. Genealogical records previously estimated the contribution of non-Europeans into the
Afrikaners to be between 5.5 and 7.2%.
RESULTS : To investigate the genetic ancestry of the Afrikaner population today (11–13 generations after initial
colonization), we genotyped approximately five million genome-wide markers in 77 Afrikaner individuals and
compared their genotypes to populations across the world to determine parental source populations and
admixture proportions. We found that the majority of Afrikaner ancestry (average 95.3%) came from European
populations (specifically northwestern European populations), but that almost all Afrikaners had admixture from
non-Europeans. The non-European admixture originated mostly from people who were brought to South Africa as
slaves and, to a lesser extent, from local Khoe-San groups. Furthermore, despite a potentially small founding
population, there is no sign of a recent bottleneck in the Afrikaner compared to other European populations.
Admixture amongst diverse groups from Europe and elsewhere during early colonial times might have
counterbalanced the effects of a small founding population.
CONCLUSIONS : While Afrikaners have an ancestry predominantly from northwestern Europe, non-European admixture
signals are ubiquitous in the Afrikaner population. Interesting patterns and similarities could be observed between
genealogical predictions and our genetic inferences. Afrikaners today have comparable inbreeding levels to current-day
European populations.
