We previously proposed a prediction model consisting of 9 CpG sites for forensic age estimation with high practical potentials in Chinese males. Here, we further evaluated the performance of this prediction model in two independent batches of time-series bloodstain samples naturally exposed to room temperature conditions. The first batch consists of 30 Han Chinese males (18–59 years of age) whose peripheral blood was converted into bloodstains on Flinders Technology Association (FTA) cards and naturally exposed to room temperature conditions for different time points up to 3 months. The second batch consists of 99 Han Chinese males (21–66 years of age) whose peripheral blood was divided into 3 replicates, converted into bloodstains on gauze, and naturally exposed to room temperature conditions for 3 months. For each time point and each replicate, the methylation levels at the 9 CpG sites were detected using the EpiTYPER system. Applying the 9- CpG age prediction model to these bloodstain samples resulted in highly accurate age predictions for all time points and replicates (0.81 < R2 < 0.91, 2.94 < MAD < 3.55 years). The updated model combining our previous and current data achieved similarly high prediction results. Therefore, our 9-CpG age prediction model was successfully validated in time-series bloodstain samples converted on both FTA card and gauze under natural room temperature conditions, demonstrating high potentials in future forensic applications to Han Chinese males.

Additional Metadata
Persistent URL dx.doi.org/10.1016/j.fsigen.2019.03.006, hdl.handle.net/1765/116370
Journal Forensic Science International: Genetics
Peng, F.D., Feng, L., Chen, J., Wang, L, Li, P., Ji, A.Q., … Li, C. X. (2019). Validation of methylation-based forensic age estimation in time-series bloodstains on FTA cards and gauze at room temperature conditions. Forensic Science International: Genetics, 40, 168–174. doi:10.1016/j.fsigen.2019.03.006