Systematic analysis of full-sibling identification by adding genetic markers and reference relatives

Area of Science:

• Forensic Science
• Genetics
• Population Genetics

Background:

• Full-sibling (FS) identification is vital in kinship analysis but current methods lack routine accuracy.
• Enhancing the precision of FS identification is crucial for forensic applications.

Purpose of the Study:

• To assess optimal cut-off values for FS identification using identical by state (IBS) and likelihood ratio (LR) methods.
• To evaluate the accuracy and effectiveness of FS identification with varying numbers of short tandem repeats (STRs) under different error rates.

Main Methods:

• Incorporated IBS and LR methods to determine optimal cut-off values for FS identification.
• Calculated sensitivity, specificity, accuracy, and effectiveness across 19 to 55 STRs.
• Validated cut-off values using authentic Han population pedigrees from East China.

Main Results:

• Dependable and practical cut-off values were identified for IBS and LR methods with error rates below 0.01%.
• The study analyzed the influence of half-sibling relationships and reference relatives on FS identification.
• Validated cut-off values demonstrated high accuracy in authentic pedigrees.

Conclusions:

• Optimized cut-off values enhance the reliability of FS identification in forensic contexts.
• The findings support the practical application of improved FS identification methods in China.
• An updated technical specification for FS identification in China provides a valuable resource for forensic testing.