Numerical expression of paternity test results using predetermined indexes

Area of Science:

• Forensic Genetics
• Human Identification
• Statistical Genetics

Background:

• Paternity testing relies on genetic markers to establish biological relationships.
• The Paternity Index (PI) is a statistical measure of the strength of evidence for paternity.
• Converting PI to a more interpretable format is crucial for reporting.

Purpose of the Study:

• To explain the calculation and application of Relative Chance of Paternity (RCP).
• To demonstrate how RCP provides a clear percentage for paternity or non-paternity.
• To outline the process of deriving RCP from genetic marker data.

Main Methods:

• Calculating the Paternity Index (PI) for individual genetic markers.
• Combining PI values across multiple genetic markers for a trio (mother, child, alleged father).
• Converting the combined PI to Relative Chance of Paternity (RCP) using the formula RCP = PI/(PI+1).

Main Results:

• RCP provides a numerical expression ranging from 0% (non-paternity) to near 100% (paternity).
• Pre-determined PI values for various genetic marker systems are available in tables.
• The method allows for straightforward qualitative and quantitative reporting of paternity testing results.

Conclusions:

• RCP offers a standardized and easily understandable metric for paternity testing outcomes.
• The conversion of PI to RCP simplifies the interpretation of complex genetic data.
• This approach enhances the clarity and utility of paternity testing reports.