Evaluación de los resultados de ADN para la identificación de víctimas de derechos humanos en Chile

Identifying victims of human rights violations pertaining to the dictatorship in Chile is essential for the pursuit of truth, justice and reparation. The Human Rights Unit in Servicio Médico Legal from Chile, uses DNA analysis of bone samples to identify human rights victims from this period. An evaluation of data related to each case was conducted to assess the influence of variables on identification outcomes (number of short tandem repeats amplified or STR). Six factors were analysed statistically: the post-mortem interval (PMI), the geographic zone of the sample’s exhumation, the victim’s age at death, preservation of the bone sample, the type of bone, and the sample’s weight. The main aim was to determine the most appropriate conditions to optimise DNA outcomes. The results indicated a significant difference in the number of STR amplified within groups for PMI ((H2,393=46.28, p<0.05), the geographic zone of exhumation (H2,393=51.45, p<0.05), bone preservation (H2,393=6.30, p<0,05) and type of bone analysed (H13,382=32.86, p<0,05). Attempts to model the relationship between factors and DNA outcomes using stepwise linear regression analysis of 396 samples indicate that PMI is significantly related to the amount of DNA amplified (F1,394=34.95, p<0.05), as is the combination of PMI and bone preservation (F2,393=19.61, p<0.05). These two factors accounted for 86% of the variation observed in DNA outcomes. Conclusively, samples from bones with longer PMI and ‘poor’ preservation result in lower DNA amplified than samples extracted from shorter PMIs with ‘good preservation.