Age estimation of burnt human remains through DNA methylation analysis

Area of Science:

• Forensic Science
• Epigenetics
• Human Identification

Background:

• Identifying fire victims is difficult due to heat damage to tissues, often hindering conventional anthropological and DNA database matching.
• DNA methylation analysis offers a potential avenue for generating investigative leads when standard identification methods are insufficient.

Purpose of the Study:

• To develop and validate an age prediction model using age-related epigenetic markers in blood for identifying human fire victims.
• To assess the reliability and accuracy of DNA methylation analysis for chronological age estimation in burnt human remains.

Main Methods:

• Five age-related epigenetic markers (ELOVL2, FHL2, KLF14, C1orf132, TRIM59) were analyzed in blood samples from 72 living individuals using a Single Base Extension (SBE) assay.
• A multiple linear regression model was constructed to predict age, achieving a Mean Absolute Error (MAE) of 3.15 years in living individuals.
• The model was subsequently tested on 29 blood samples from burnt human remains, yielding an MAE of 6.92 years.

Main Results:

• The developed age prediction model demonstrated a MAE of 6.92 years when applied to burnt human remains.
• The model achieved correct age predictions within a 95% prediction interval in 79.3% of the burnt samples.
• DNA degradation was identified as a significant factor influencing the accuracy of age predictions in severely damaged samples.

Conclusions:

• Single Base Extension (SBE) typing of blood from burnt remains is a reliable and cost-effective tool for estimating chronological age.
• This epigenetic approach provides valuable investigative leads for the identification of fire victims, complementing existing forensic techniques.
• The method's feasibility is enhanced by the widespread availability of capillary electrophoresis sequencers in forensic genetics laboratories.