Towards a multidisciplinary population profiling of southern Angola: a key region for understanding human settlement in southern Africa

Portuguese Foundation for Science and Technology (FCT): PTDC/BIA-EVF/2907/2012

Duration: 2013-2015

Principal Investigator: Jorge Rocha

​

 

This project aimed at inferring the population history that gave rise to the current patterns of human diversity in southern Angola, using a multidisciplinary approach with a strong emphasis on population genetics. Specifically, we explored the working hypothesis that the unique combination of linguistic, cultural and biological features observed in the region was shaped by three major confluent migratory movements which led to the present human variability in the wider area of southern Africa: i) an early occupation by "Khoisan" foragers; ii) a more recent intrusion of Pre-Bantu pastoralist peoples from East Africa, speaking Khoe-Kwadi languages and introducing fat-tailed sheep and possibly also longhorn taurine cattle ; iii) a subsequent arrival of Bantu-speaking groups relying to various degrees on agricultural and pastoral lifeways based on different breeds of livestock.

​

The importance of southern Angola for understanding human settlement in southern Africa is due to a number of key features that provide an ideal framework to examine the history and consequences of population contact. The region is linguistically and bio-culturally very diverse, with overlapping population strata that include Kx'a-speaking forager groups, Bantu-speaking peoples with different combinations of agricultural and pastoral subsistence, and peripatetic remnant populations that are likely to descend from Pre-Bantu groups, one of whom is known to have spoken the extinct Kwadi branch of the Khoe-Kwadi language family.

​

The sharpness of the often assumed dichotomy between hunter-gatherer peoples and their food-producing neighbors, the origin and migration routes of the ancestors of southwestern Bantu peoples, as well as the role played by Pre-Bantu herders in the emergence of the southwestern African pastoral scene were all unsolved questions whose resolution critically depended on the thorough characterization of multiple dimensions of human variation in southern Angola. Since, prior to this project, little effort had been done to perform such study, we undertook a multidisciplinary initiative based on contributions from human population genetics, livestock genetics and linguistics, in order to obtain for the first time a comprehensive profile of six representative populations from the provinces of Namibe, Huíla and Kunene: i) Sekele (!Xun); ii) Kwepe; iii) Twa and Kwisi; iv) Nyaneka-Nkhumbi; v) Himba; vi) Kuvale.

​

The human genetics study led to the generation of likely evolutionary scenarios of population movement, demographic change and admixture, which were jointly considered with data from other disciplines. Benefiting from recent developments in high-throughput sequencing and typing technologies, the study provided a thorough characterization of human genetic variation based on the sequencing of complete mtDNA genomes (Barbieri et al. 2013, 2014; Oliveira et al. 2018, AJPA), target sequencing of a 500kb segment of Y chromosome (Oliveira et al. 2018, Eur. J. Hum. Gen.) and typing of approximately 600,000 single nucleotide polymorphisms, specifically selected for human micro-evolutionary studies (Oliveira et al. 2023, Sci. Adv.).

​

Given the importance of livelihoods - especially pastoralism - in the subsistence of southern Angolan peoples, we further studied the oral microbiome (Araújo et al. 2023) and the distribution of Lactase Persistence in the region (Pinto et al. 2016). Taking into account the close association of livestock species to human migration, we additionally used a multi-marker approach to assess the genetic variation of the poorly characterized sheep and cattle populations owned by the pastoralist and agro-pastoralist populations included in the study. The inclusion of the linguistic component turned out to be crucial, as some of the most relevant historical hypotheses about the peopling of southern Africa had been based on the analysis of language data. The linguistic study contributed to improve the documentation of Bantu and non-Bantu languages of the area (Oliveira et al. 2018, AJPA; Fehn 2019, Fehn 2020), and led to a comprehensive historical-comparative reconstruction substantiating the existence of a Khoe-Kwadi language family (Fehn & Rocha, forthc.).

 

The multidisciplinary nature of the project and its conceptual focus on admixture were highly innovative and ended up providing a significant contribution towards a unified picture of the peopling of southern Africa, including the discovery of a previously unknown ancestry component in the Kwisi, Twa and Kwepe (Oliveira et al. 2023). The research team was formed by specialists in the disciplines involved and included a collaborative effort with Angolan institutions, i.e. the Instituto Superior de Ciências da Educação (ISCED-Huíla) in Lubango (Huíla) and the Centro de Estudos do Deserto (CEDO) in Curoca, as well as with the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.