Developing a male-specific age predictive model based on Y-CpGs for forensic analysis.

Area of Science:

• Forensic Science
• Genetics
• Epigenetics

Background:

• Epigenetic age estimation is crucial in forensics but often limited to autosomal DNA.
• Existing models struggle with mixed DNA samples, hindering investigations.

Purpose of the Study:

• To develop a male-specific epigenetic age prediction model using Y-chromosome CpGs.
• To validate the model's accuracy and applicability in forensic contexts.

Main Methods:

• Screened methylation data to identify Y-CpGs.
• Established a male-specific age prediction model using 2 SNaPshot systems with 13 Y-CpGs.
• Validated the model for sensitivity and specificity.

Main Results:

• Achieved mean absolute deviations (MAD) of 4-6 years for age prediction.
• Demonstrated high performance on training (R²=0.9341, MAD=4.65) and test sets (R²=0.8952, MAD=5.73).
• Showed applicability to bloodstains and acceptable accuracy (<8 years deviation) in male-female DNA mixtures.

Conclusions:

• The Y-CpG based model is a sensitive and specific tool for male age prediction in forensics.
• The method shows promise for analyzing mixed DNA samples and in cases like sexual assault.
• This research establishes a foundation for using Y-CpGs in forensic age estimation.