Analysis of Y-chromosome STRs in Chile confirms an extensive introgression of European male lineages in urban populations.

We analyzed the Y chromosome haplotypes (Yfiler) of 978 non-related Chilean males grouped in five sampling regions (Iquique, Santiago de Chile, Concepción, Temuco and Punta Arenas) covering main geo-political regions. Overall, 803 different haplotypes and 688 singletons were observed. Molecular diversity was moderately lower than in other neighboring countries (e.g. Argentina); and AMOVA analysis on Y-STR haplotypes showed that among variation within Chile accounted for only 0.25% of the total variation. Punta Arenas, in the southern cone, showed the lowest haplotype diversity, and discrimination capacity, and also the highest matching probability of the five Chilean samples, probably reflecting its more marked geographic isolation compared to the other regions. Multidimensional scaling (MDS) analysis based on RST genetic distances suggested a close proximity of Chilean Y-chromosome profiles to European ones. Consistently, haplogroups inferred from Y-STR profiles revealed that the Native American component constituted only 8% of all the haplotypes, and this component ranged from 5% in the Centre of the country to 9-10% in the South and 13% in the North, which is in good agreement with the distribution of Native American communities in these regions. AMOVA computed on inferred haplogroups confirmed the very low among variation observed in Chilean populations. The present project provides the first Chilean dataset to the international Y-chromosome STR Haplotype Reference Database (YHRD) and it is also the first reference database for Y-chromosome forensic casework of the country.

A reference frequency database of 15 autosomal STRs in Chile.

We estimated the allele frequencies for the 15 autosomal STR loci included in the AmpFlSTR(®) Identifiler (Applied Biosystems, USA) in a sample of 986 unrelated non-Native American individuals collected at five different localities from Chile, namely, Iquique, Santiago, Concepción, Temuco and Punta Arenas. Frequency distributions and several forensic parameters were estimated at each recruitment site. In addition, analyses were carried out merging the data into five sample locations. No significant statistical differences could be detected between different regions in Chile. These data represent one of the very few studies performed on autosomal STRs in Chile and therefore provide a useful tool for forensic casework carried out in the country.