Consistency of Familial DNA Search Results in Southeast Asian Populations

TL;DR

This study evaluates different likelihood ratio strategies for familial DNA searches in Southeast Asian populations, highlighting the effectiveness of the minimum likelihood ratio approach in Thai subpopulations for forensic identification.

Contribution

It provides the first assessment of familial DNA search strategies specifically in Southeast Asian populations, comparing their effectiveness across different subpopulations.

Findings

Minimum likelihood ratio strategy performs best in Thai subpopulations.

Statistical power varies significantly across different strategies.

Effectiveness of strategies differs among Southeast Asian populations.

Abstract

DNA databases are widely used in forensic science to identify unknown offenders. When no exact match is found, familial DNA searches can help by identifying first-degree relatives using likelihood ratios. If multiple subpopulations are relevant, likelihood ratios can be computed separately based on allele frequency estimates. Various strategies exist to combine these ratios, such as averaging allele frequencies or taking the average, maximum, or minimum likelihood ratio. While some comparisons have been made in populations like those in the U.S., their effectiveness in other regions remains unclear. This study evaluates likelihood ratio-based strategies in Southeast Asian populations, specifically Thailand, Malaysia, and Singapore. Our findings align with previous research, showing that statistical power varies across strategies. Among Thai subpopulations, the minimum likelihood ratio strategy is preferred, as it maintains high power while minimizing differences between subpopulations.