Interpreting mismatches between linguistic and genetic patterns among speakers of Tanimuka (Eastern Tukanoan) and Yukuna (Arawakan)

The genetic history of the Southern Andes from present-day Mapuche ancestry

The southernmost regions of South America harbor some of the earliest evidence of human presence in the Americas. However, connections with the rest of the continent and the contextualization of present-day indigenous ancestries remain poorly resolved. In this study, we analyze the genetic ancestry of one of the largest indigenous groups in South America: the Mapuche. We generate genome-wide data from 64 participants from three Mapuche populations in Southern Chile: Pehuenche, Lafkenche, and Huilliche. Broadly, we describe three main ancestry blocks with a common origin, which characterize the Southern Cone, the Central Andes, and Amazonia. Within the Southern Cone, ancestors of the Mapuche lineages differentiated from those of the Far South during the Middle Holocene and did not experience further migration waves from the north. We find that the deep genetic split between the Central and Southern Andes is followed by instances of gene flow, which may have accompanied the southward spread of cultural traits from the Central Andes, including crops and loanwords from Quechua into Mapudungun (the language of the Mapuche). Finally, we report close genetic relatedness between the three populations analyzed, with the Huilliche characterized additionally by intense recent exchanges with the Far South. Our findings add new perspectives on the genetic (pre)history of South America, from the first settlement through to the present-day indigenous presence. Follow-up fieldwork took these results back to the indigenous communities to contextualize the genetic narrative alongside indigenous knowledge and perspectives.

Interpreting mismatches between linguistic and genetic patterns among speakers of Tanimuka (Eastern Tukanoan) and Yukuna (Arawakan)

Northwestern Amazonia is home to a great degree of linguistic diversity, and the human societies in that region are part of complex networks of interaction that predate the arrival of Europeans. This study investigates the population and language contact dynamics between two languages found within this region, Yukuna and Tanimuka, which belong to the Arawakan and Tukanoan language families, respectively. We use evidence from linguistics, ethnohistory, ethnography and population genetics to provide new insights into the contact dynamics between these and other human groups in NWA. Our results show that the interaction between these groups intensified in the last 500 years, to the point that it is difficult to differentiate between them genetically. However, this close interaction has led to more substantial contact-induced language changes in Tanimuka than in Yukuna, consistent with a scenario of language shift and asymmetrical power relations.

Diversity, multilingualism and inter-ethnic relations in the long-term history of the Upper Rio Negro region of the Amazon

The Upper Rio Negro regional social system is made up of more than 30 languages belonging to six linguistic families. This results from socio-historical processes stretching back at least two millennia, which have built a system with different levels of autonomy and hierarchy associated with a mythical and ritual complex, and with social and linguistic exchanges. The analysis of these processes require an interdisciplinary outlook to understand the ways in which people from different linguistic families interacted and created it. More specifically, we ask how linguistic and cultural diversity have been created in the context of intense relations of multilingualism and inter-ethnic contact. To this end, we integrate perspectives from historical linguistics (regarding languages from the Tukanoan, Arawakan and Naduhup families) with archaeological data from the Amazonian past. Through this multidisciplinary approach, we seek to develop a linguistic-anthropological understanding of the dynamics shaping the region's diversity and inter-ethnic relations. We show that processes creating diversity are interrelated with changes in social histories, and are especially tied to the establishment of new forms of social organization as a result of pre-colonial inter-ethnic relations. This has led to the construction of various local multilingual ecologies connected to macro-regional processes in Amazonia.

Multidisciplinary approaches to the Amazonian past: introduction to the theme issue

This theme issue presents collaborative research by anthropologists, linguists, archaeologists, geneticists, historians and biogeographers, who work across disciplinary boundaries to investigate the Amazonian past. Amazonia is a fertile ground in which to develop such multidisciplinary approaches because its relative paucity of documentary records makes other sources of evidence regarding the past more important; because multidisciplinary approaches are well suited to address important unanswered questions in Amazonian history; and because a recent and dramatic reappraisal of the region's past make this an exciting time to conduct this sort of research. The papers in this theme issue feature different combinations of academic disciplines, and they address different geographical regions and historical periods, but all of them show how combining insights from different fields can help illuminate aspects of the Amazonian past that would otherwise remain obscure to them all.