Forensic genetic analysis of bone remain samples.

Area of Science:

• Forensic Science
• Molecular Biology
• Bioarchaeology

Background:

• DNA typing from degraded human remains presents significant challenges in purification, profile interpretation, and data management, particularly in mass fatality incidents.
• Existing methods struggle with varying degrees of decomposition, impacting the reliability of forensic DNA analysis.

Purpose of the Study:

• To present a DNA typing protocol for investigating skeletal remains with varying decomposition levels.
• To establish a grading system for predicting Short Tandem Repeat (STR) amplification success based on decomposition and bone type.
• To optimize DNA isolation and STR profiling for challenging forensic cases.

Main Methods:

• A modified DNA IQ™ System was used for DNA isolation from 80 bone samples.
• STR analysis was performed using the AmpFLSTR Identifiler® kit.
• Samples were categorized into low, medium, and high destruction groups based on decomposition levels.

Main Results:

• Complete STR profiles were obtained from 84.4% of low destruction samples, with partial profiles in 9.4% and non-amplification in 6.2%.
• Medium destruction samples yielded 31.2% complete or partial STR profiles, with 37.5% failing to amplify.
• No DNA profiles were generated from highly destroyed bone samples.
• Compact bones (femur, humerus) showed higher amplification success than spongy bones.
• Costal cartilage proved effective for DNA isolation within 3 days post-mortem, yielding high-quality DNA with reduced time and cost.

Conclusions:

• The developed DNA typing protocol and grading system aid in assessing STR amplification efficacy from degraded skeletal remains.
• Compact bone types and costal cartilage are recommended specimens for improved DNA recovery in forensic investigations.
• The findings contribute to more effective DNA profiling strategies for challenging forensic samples, especially in mass fatalities.