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 comprehensive Y-STR portrait of Argentinean populations.

A study of 23 Y-STRs was conducted in 257 individuals living in urban areas from eight Argentinean provinces. The data were meta-analyzed together with 364 profiles obtained from the literature that represent other five provinces. A total of 255 different haplotypes were observed (253 singletons). Genetic structure estimated from analysis of molecular variance (AMOVA) and exploring different grouping scenarios, yielded high within population variance. Not surprisingly, analyses of genetic distances with respect to main ancestral continental populations indicated Argentinean haplotypes to be closely related to European ones. Overall, these results provide a quite complete picture of the patterns of Y chromosome variation in Argentina, notably contributing to increase the previous national database, and consequently allowing a better estimation of parameters of interest in forensic casework and parentage testing.