Subsistence transition preceded population turnover in the eastern Colombian Andes

Area of Science:

• * Paleogenomics and population genetics
• * Archaeology and anthropology of South America
• * Human dispersals and cultural evolution in the Holocene

Background:

• * Northwest South America, particularly the Altiplano Cundiboyacense in Colombia, is crucial for understanding Holocene human dispersals and cultural exchanges.
• * This region possesses a rich archaeological record spanning from the late Pleistocene to the late Holocene Muisca chiefdoms.
• * Previous ancient DNA studies identified a population turnover but lacked data for a critical period (6000-2000 BP), leaving the nature of the shift unresolved.

Purpose of the Study:

• * To reconstruct the population history of the Altiplano Cundiboyacense over 7000 years using ancient DNA.
• * To investigate the relationship between subsistence changes (maize adoption) and population dynamics.
• * To identify the ancestry of populations associated with the Herrera and Muisca cultures.

Main Methods:

• * Generation of genome-wide ancient DNA data from 209 individuals spanning over 7000 years.
• * Radiocarbon dating and stable isotope analysis (δ¹³C) to determine diet.
• * Population genetic analyses, including admixture proportions and phylogenetic relationships, compared with modern Native American populations.

Main Results:

• * A persistent lineage of hunter-gatherers existed for over five millennia with no significant external gene flow.
• * Individuals predating the Herrera Period (~2800 years ago) showed maize in their diet without evidence of population replacement.
• * A sharp genetic discontinuity emerged around 2200 BP with the arrival of a new population admixed between Chibchan-related groups and Amazonian-Andean populations, coinciding with the Herrera culture.

Conclusions:

• * Subsistence strategies, such as maize adoption, could change independently of population replacement.
• * The emergence of the Herrera culture was associated with a significant migration event and population turnover.
• * Later populations in the Altiplano Cundiboyacense derive ancestry from admixture events involving groups related to lower Central American Chibchan speakers and Amazonian-Andean populations.