Social injustice unveiled by genetic analysis: Argentina as a case study.

BACKGROUND: The population of the American countries is genetically heterogeneous, whose genesis result from of recent admixture events. In this process, the transoceanic European component displaced the original inhabitants of the continent. AIM: To investigate whether socially differentiated cohorts exhibit underlying ancestry components within an urban admixed population, two cohorts of individuals inhabiting Argentina were studied. One cohort included genetically unrelated individuals involved in voluntary paternity testing while the other included sexual or blood-crime suspects. MATERIALS & METHODS: We analyzed over 2500 unrelated individuals: four Native American maternal lineage mtDNA markers in 1024 samples, five Y chromosome haplogroups in 658 male samples, 24 autosomal ancestry informative markers (AIMs) in 205 samples, and 15 autosomal short tandem repeats (STRs) in 1557 samples; countrywide and divided by regions. RESULTS: While our results confirm a tricontinental ethnic contribution to both cohorts, their proportions showed statistically significant differences, with a higher proportion of Native American ancestry in the cohort linked to violent crimes compared to those in paternity testing. This hallmark was observed with all the marker sets used and at various levels of analysis. DISCUSSION: Since paternity tests are costly, socio-economic differences might help to interpret our observations. The effect of discrimination against descendants of Native American minorities, and exposure to violent social environments, might link marginal groups to criminality. CONCLUSION: Our findings underscore the relevance of proper social management since only by improving living conditions, reducing discrimination, promoting education, and providing job opportunities will it be possible to attain equality in a heterogeneous society. Genetic markers proved to be highly informative in unveiling unexpected social differences.