Southern and eastern African populations that speak non-Bantu languages with click consonants are known to harbour some of the most ancient genetic lineages in humans, but their relationships are poorly understood. Here, we report data from 23 populations analysed at over half a million single-nucleotide polymorphisms, using a genome-wide array designed for studying human history. The southern African Khoisan fall into two genetic groups, loosely corresponding to the northwestern and southeastern Kalahari, which we show separated within the last 30,000 years. We find that all individuals derive at least a few percent of their genomes from admixture with non-Khoisan populations that began ∼1,200 years ago. In addition, the East African Hadza and Sandawe derive a fraction of their ancestry from admixture with a population related to the Khoisan, supporting the hypothesis of an ancient link between southern and eastern Africa.

Preface and acknowledgments v List of maps, tables, and figures xiv Abbreviations and conventions xviii Representation of linguistic examples xviii Abbreviations xix Other symbols and fonts xxi 1 The framework, aim, and data of this study 1 1.1 Topic and research questions 1 1.2 Theoretical preliminaries 3 1.2.1 Reported discourse and its categories 4 1.2.2 Quotative indexes as formal signals of reported discourse 1.3 Methodological preliminaries 1.3.1 Language sample, sources, and data corpus 1.3.2 The analysis of quotative indexes 1.3.3 Elements of quotative indexes used with other functions 1.4 An overview of reported-discourse constructions in the corpus 1.4.1 Non-direct reported discourse 1.4.2 Free direct reported discourse 2 The internal structure of quotative indexes 2.1 The predicative assertion and predication operators 2.1.1 Predicative vs. non-predicative quotative indexes 2.1.2 Deviation from canonical predicativity ("marked predicativity") 2.1.3 Marked lexical features of predicative items 2.1.

The Khoisan populations of southern Africa are known to harbor some of the deepest-rooting lineages of human mtDNA; however, their relationships are as yet poorly understood. Here, we report the results of analyses of complete mtDNA genome sequences from nearly 700 individuals representing 26 populations of southern Africa who speak diverse Khoisan and Bantu languages. Our data reveal a multilayered history of the indigenous populations of southern Africa, who are likely to be the result of admixture of different genetic substrates, such as resident forager populations and pre-Bantu pastoralists from East Africa. We find high levels of genetic differentiation of the Khoisan populations, which can be explained by the effect of drift together with a partial uxorilocal/multilocal residence pattern. Furthermore, there is evidence of extensive contact, not only between geographically proximate groups, but also across wider areas. The results of this contact, which may have played a role in the diffusion of common cultural and linguistic features, are especially evident in the Khoisan populations of the central Kalahari.