Colloquium paper: working toward a synthesis of archaeological, linguistic, and genetic data for inferring African population history

Abstract

isentangling past population histories is a formidably complicated task that benefits from the synthesis of archaeological, linguistic, and genetic data. Archaeology permits insights into ancient technology and culture and provides a timetable for the emergence of innovations. Historical linguistic data complement the archaeological record by contributing an independent phylogenetic analysis of language relationships and providing clues about ancient population migration and admixture events. Similarly, genetic data provide an independent data source to understand the biological relationships among modern peoples and likely points of origin and expansion of their ancestors. Undoubtedly, the specific details of human demographic history are more complex than any synthesis can account for, but we are focusing here on the overlap among the archaeological, linguistic, and genetic data collected in Africa to make inferences about African demographic history. African Language Family Classification Africa is home to almost a third of all modern languages, encompassing >2,000 ethno-linguistic groups (1) that have largely been classified into four language families: Niger-Kordofanian, Afroasiatic, Nilo-Saharan, and Khoesan. As displayed in Fig. 1, Niger-Kordofanian languages are spoken throughout western Africa, eastern Africa, central Africa, and southern Africa and include the common Bantu languages. The Afroasiatic language family includes languages spoken in northern, central, and eastern Africa such as Cushitic, Chadic, Semitic, and ancient Egyptian. The Nilo-Saharan language family is spoken predominantly in central and eastern Africa and includes the Sudanic and Nilotic languages. The Khoesan language family, which includes languages that contain click consonants and is spoken by hunter– gatherer populations in eastern (Hadza and Sandawe) and southern Africa [the San, referred to here as “southern African Khoesan” (“SAK”)], is the most contentious of the African language families because there is so much divergence among the Hadza, Sandawe, and SAK languages (2, 3). Modern Human Origins and Migration out of Africa The earliest emergence of anatomically modern humans in the fossil record occurred in eastern Africa 200–150 thousand years ago (kya) (4–7). Although the earliest dated modern humans outside of Africa were identified in the Middle East ∼90 kya (5, 8–