Ancestry and admixture of a southernmost Chilean population: The reflection of a migratory history.

Objectives: Punta Arenas is a Chilean city situated on ancestral Aönikenk territory. The city was founded by 19th- and 20th-century colonists from Chile (Chiloé) and Europe (Croatia). This work uses uniparental and ancestry-informative markers (AIMs) to explore the effects of historic migratory and admixture patterns on the current genetic composition of Punta Arenas.

Methods: We analyzed mitochondrial DNA (mtDNA), Y-chromosome single-nucleotide polymorphisms (SNPs), and 141 AIMs obtained from 129 DNA samples from male residents with regional ancestry. After characterizing uniparental lineages and ancestry proportions, multivariate analysis was used to explore relationships among the various types of data.

Results: Punta Arenas has an admixed population with three main genetic components: European (56.5%), northern Native (11.3%), and south-central Native (28.6%). The Native component is preponderant in the mtDNA (83.76%), while the foreign component predominates in the Y-chromosome (92.25%). Non-Native mtDNA lineages are associated with European genetic ancestry, and Native mtDNA lineages originated mainly in the southern and southernmost regions of Chile. Most non-Native Y-chromosome SNPs originated in Spain, and secondly, in Croatia.

Conclusions: The population of Punta Arenas is mainly of Chilote origin with south-central Native and Spanish ancestral components, as well as some Croatian components. The persistence of local Native lineages is notable, suggesting continuity with the ancestral populations of the region such as the Kawésqar, Aönikenk, Yámana, or Selknam peoples. This study contributes to our knowledge of local history and its links to national and global developments in genetic ancestry.