Genetic polymorphism of 15 STR loci in agropastoral communities from central-northern Chile and relationships with other South American populations

The agropastoral communities of Coquimbo, Chile, are characterised by their goat herding-based livelihoods, admixed ancestry, and transhumant mobility. To explore the impact of these features on genetic diversity and interactions with neighbouring populations. Genotypic polymorphisms of 15 STRs were analysed in 466 individuals from 15 communities. Forensic parameters were estimated. Genetic structure was assessed using RST, Nei’s distances, MDS, dendrograms, and STRUCTURE, with 23 reference populations from Chile, South America and globally. A total of 158 alleles were observed, with frequencies ranging from 0.0011 to 0.5172. CSF1PO, D18S51, and Penta E showed deviation from Hardy-Weinberg equilibrium. The panel demonstrated high forensic performance (combined power of discrimination CPD > 0.999999999, combined power of exclusion CPE = 0.99999713817). No clear genetic structure was found within the Coquimbo communities. Regionally, Coquimbo clustered with northern Chile and north-west Argentina. Globally, it resembled other South American admixed populations, slightly differentiated from those from other regions. The STRs analysed show high forensic potential, low genetic structure within the agropastoral communities, and important similarities with populations in northern Chile and north-west Argentina, supporting the relevance of trans-Andean mobility in shaping their genetic landscape.