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Single nucleotide polymorphisms (SNPs) are the most abundant genetic markers in the human genome. SNPs are used in forensics for predicting the externally visible characteristics of a given individual based on a sample of DNA alone. In this study, we tested degraded DNA samples to determine the eye color prediction accuracy of the IrisPlex system. We used five years old bloodstains and UVC exposed (30 and 60 min) DNA samples. PCR and electrophoresis were performed. The multinomial logistic regression model statistics is applied for eye color prediction. We observed allele and locus drop-outs on both bloodstains stored for five years and UVC exposed samples. The brown and blue eye colors were correctly predicted for reference and degraded samples. The intermediate eye colors were predicted to be brown or inconclusive. The degradation by aging bloodstains or UVC exposure, is differently affected the prediction accuracy depending on the informativeness of the SNPs. This study showed that the prediction of the eye color is highly accurate for the blue and brown eye colored individuals. However, the IrisPlex prediction accuracy could be influenced by the old and degraded samples. Istanbul University, Scientific Research FundIstanbul University [41343, 26105] This study was supported by Istanbul University, Scientific Research Fund (Project No: 41343 and 26105).

Aim To analyze two phenotype characteristics – eye and hair color – using single-nucleotide polymorphisms (SNPs) and evaluate their prediction accuracy in Slovenian population. Methods Twelve SNPs (OCA2 – rs1667394, rs7170989, rs1800407, rs7495174; HERC2 – rs1129038, rs12913832; MC1R – rs1805005, rs1805008; TYR – rs1393350; SLC45A2 – rs16891982, rs26722; SLC24A5 – rs1426654) were used for the development of a single multiplex assay. The single multiplex assay was based on SNaPshot chemistry and capillary electrophoresis. In order to evaluate the accuracy of the prediction of eye and hair color, we used the logistic regression model and the Bayesian network model, and compared the parameters of both. Results The new single multiplex assay displayed high levels of genotyping sensitivity with complete profiles generated from as little as 62 pg of DNA. Based on a prior evaluation of all SNPs in a single multiplex, we focused on the five most statistically significant in our population in order to investigate the predictive value. The two prediction models performed reliably without prior ancestry information, and revealed very good accuracy for both eye and hair color. Both models determined the highest predictive value for rs12913832 (P