Age estimation based on different molecular clocks in several tissues and a multivariate approach: an explorative...

Area of Science:

• Forensic Science
• Biogerontology
• Molecular Biology

Background:

• Aging is characterized by molecular changes, including DNA and protein modifications, serving as potential "molecular clocks" for age estimation.
• Current forensic age estimation methods using molecular clocks face limitations due to individual aging variations influenced by intrinsic and extrinsic factors.
• A comprehensive approach combining multiple molecular clocks across different tissues may overcome these limitations for more precise age determination.

Purpose of the Study:

• To test the hypothesis that combining different molecular clocks in various tissues improves the accuracy of forensic age estimation.
• To evaluate the efficacy of analyzing D-aspartic acid (D-Asp) and pentosidine (PEN) accumulation in intervertebral disc and epiglottis tissues for age prediction.

Main Methods:

• Analysis of two protein-based molecular clocks: D-aspartic acid accumulation and pentosidine accumulation.
• Examination of tissues: annulus fibrosus of intervertebral discs and elastic cartilage of the epiglottis.
• Development and comparison of univariate and multivariate models for age estimation using data from 95 cases.

Main Results:

• The inclusion of more parameters in age estimation models progressively reduced mean absolute errors (MAE).
• Univariate models yielded MAEs ranging from 7.5 to 11.0 years.
• A multivariate model integrating both protein clocks across the two tissues achieved a significantly lower MAE of 4.0 years.

Conclusions:

• Combining different molecular clocks (D-Asp, PEN) in distinct tissues (intervertebral disc, epiglottis) enhances postmortem age estimation accuracy.
• This multi-marker, multi-tissue approach offers a more comprehensive analysis of individual aging processes.
• Future research will incorporate epigenetic clocks (DNA methylation) and expand the range of tissues analyzed.