The Analysis of a B2 Mitochondrial Sub-Lineage from the Chilean Andes Supports Complex Mobility Patterns Between...

This study aims to delve into mobility patterns and demographic movements in the Andes Altiplano, based on mitochondrial DNA analyses, by reviewing the phylogeny for two previously published lineages, B2ag and B2aj and an analysis of control region sequences to discuss the dynamics of the migratory processes that have shaped the maternal genetic variability in the Andean region. While many articles have focused on population dynamics in the Altiplano, all lack meaningful Chilean sequences.

We sequenced the complete mitogenomes of B2ag1a and B2aj haplogroups (13 and 16 samples, respectively), constructed phylogenies, calculated TMRCAs, and performed frequency maps for both haplogroups. We also sequenced the D-loop of 170 individuals from three populations and performed networks, principal coordinate analysis (PCoA), and multidimensional scaling (MDS) for 1135 individuals from 24 published populations from Argentina, Peru, and Bolivia.

We describe the B2ag1a sub-lineage, from the Chilean Altiplano, and reanalyze the B2aj. The temporal depth of both lineages, B2ag1a (9.538 BP) and B2aj (11.838 BP), is consistent with an early occupation of the Andean Altiplano. D-loop analysis shows a strong relationship between Bolivia, Chile, and Argentina, with Peru being more isolated.

The results support intensive mobility patterns between populations from different areas of the Altiplano, with a critical flux center in Tiwanaku. Moreover, the Chilean Altiplano appears to be an important migration source, mainly to Bolivia and Argentina, as well as to the Chilean north coast, while the influence of the Inca Empire, at least at the population level, seems to be minor.