Differences between Khoe-San subgroups

In 1971 Jenkins et al., combined allele frequencies from several serogenetic studies (blood groups, serum protein and red cell enzyme systems) in multivariate analysis through genetic distances. Data from gene frequencies in 10 loci in 18 southern African populations were compared though genetic distance measures coupled to clustering methods (Jenkins et al., 1971; Jenkins, 1986). Figure 1.3 A and B shows a clustered tree and Principal Component Analysis (PCA) plot adapted from the genetic distance matrix published in Jenkins (1986).

In the cluster analysis (Figure 1.3 A) all the Khoe and Khoe descendant groups cluster together. The grouping of the Hai//om within the Khoe cluster is in contrast to the theories that the Hai//om is a !Xun group that acquired the Nama language. The Hai//om does not cluster with any of the four Ju groups (!Xun-Vasekele, !Xun-Kavango valley, Ju\’hoansi,

‡X’ao//‘ãesi) but rather with two Nama groups. Interestingly, the Hai//om that inhabit northern Namibia (Figure 1.1), cluster more closely with the two southern Nama groups of Keetmanshoop and !Kuboes (Richtersveld) than the more northern Rehoboth Nama. This, however, might have to do with the various amount of admixture from Caucasoid and Bantu-speaking groups into the different Nama groups. The clustering of the Basters and Coloured populations within the Khoe cluster confirm the large inputs of Khoe groups into these two groups of hybrid ancestry.

All of the San groups except the !Xun (previously also referred to a Vasekele) form a

clustering but rather with geographic proximity. The speakers of northern San languages of the Ju linguistic group (Tsumkwe Ju\’hoansi, ‡X’ao//‘ãesi, Kavango valley !Xun and the Vasekele !Xun) does not form a uniform cluster and neither do the Khoe-speaking San groups of the central Kalahari (Naro, /Gui and //Gana). Rather the Naro (Khoe linguistic group) and ‡X’ao//‘ãesi (Ju linguistic group) who have geographically overlapping territories form the closest cluster; followed by the Ju\’hoansi (Ju) which is also geographically close. The G!ang!ai !Xun then joins the cluster also according to geographic distance. The two central Kalahari San groups /Gui and //Gana, forms a separate branch within the San cluster. This indicates that geographic separation has a greater influence on geneflow than linguistic barriers. The !Xun cluster with two Bantu-Speaking groups suggests a higher amount of Bantu-Speaking admixture.

The Bantu-speaking groups (Kgalagari from Botswana, Ngwato - a Tswana group from Botswana, Herero from Namibia) form two separate clusters that also include the Khwe and Dama who are classified as “Khoisan speaking Negros” by Jenkins (1986). The Khwe appear to be most closely related to the Herero supporting observations that the Khwe phenotypically resemble Bantu-speakers rather than Khoe-San groups. The Khwe cluster closer with the Western Bantu speaking Herero group than with the Eastern-Bantu speaking Ngwato. The Dama also clearly cluster with the Bantu-speakers confirming historic accounts that the Dama were similar genetically to Bantu-speaking people before they adopted Nama as a language, possibly a consequence of their enslavement by the Nama. This study together with others (Nurse et al., 1976; Nurse and Jenkins, 1977) have thus shown that the Khwe (as well as the Dama) have genetic profiles that are more similar to Bantu-speakers. In a further study it was found that the Khwe most closely resemble their Mbukushu neighbours and an Ambo chiefdom (the Ndonga) (Nurse and Jenkins, 1977).

The first axis on the PCA plot contains more than half of the total variation (56%) and summarises the speaking versus Khoe-San variance component. The Bantu-Speaking groups cluster to the one side of this component while the northern San (NS) groups occupy the other extreme. Even though the Dama speak a Khoe language they show very little admixture from Khoe-San groups. The Kgalagari is known to live in close

contact with the /Gui and //Gana and the relative higher Khoe-San contribution into this group is evident in the first component. The Khwe, although grouping with the Bantu-Speaking groups show a higher contribution from the Khoe-San variance component than most of the Bantu-Speaking groups. The Nama, Baster and Coloured groups are located between the San and Bantu-Speaking groups on the first component, indicating higher admixture from Bantu-Speaking groups into these groups. This evidence of geneflow from Bantu-Speaking into the Khoe and Khoe descendant groups are expected, due to enhanced contact between these groups as a consequence of the sharing of the pastoralist culture (versus the absence of pastoralism in the San groups). With exception of the Vasekele !Xun and the //Gana, all the other northern and central San groups contain little Bantu-Speaking admixture. As mentioned before, the Vasekele !Xun lived in close association with the local Ambo (Ovambo) population for centuries, from whom they learned crop cultivation and herding. The higher Bantu-Speaking component in this group is therefore not surprising. Also, the higher Bantu-Speaking component in the //Gana (G//ana) is expected since it is believed by the //Gana themselves that they originated from a intermixing of the /Gui (G/wi) and the Kgalagari.

The second and third component seem to both summarise a component of variance that exist between the Khoe groups and the !Xun groups. The second component (21%) summarises variation between the !Xun of the Kavango valley in northern Namibia and the Khoe groups. The /Gui, //Gana, Ju\’hoansi, ‡X’ao//‘ãesi and Naro occupy intermediate positions with the /Gui, //Gana located more to the !Xun side and the other three groups more towards the Khoe side. The third component separate the Vasekele !Xun from the Khoe groups with the Ju\’hoansi, ‡X’ao//‘ãesi and Naro intermediate.

This thesis will investigate the genetic relationships between different Khoe and San groups further to see if the mitochondrial, Y-chromosome and autosomal genetic variation reflect group affinities that were apparent from serological studies. Through analysis of the genetic systems this study will investigate the genetic relatedness of the Khwe to the other Khoe-San populations and to the speakers. The amount of admixture from Bantu-speakers into different Khoe-San groups will also be analysed. Furthermore this study will

The study will also focus on how physical distance between groups influence their genetic relatedness, since cluster analyses of serological studies suggest a strong influence.

Figure 1.3 A Cluster analysis of distance matrix data from Jenkins (1986).

11 loci in 18 populations. NS – Northern San, CS – Central San, BS – Bantu-speaking

Figure 1.3 B Principal Component Analysis of distance matrix data from Jenkins (1986).

11 loci in 18 populations. (axis 1 = 56.1 % variation, axis 2 = 21.1%, axis 3 = 8.1% variation)