Content area
Abstract
The calculation of the paternity index (PI) value of common bi-allelic genotypes at STR loci has been standardized in paternity cases. However, for tri-allelic patterns, a rare category of genotyping aberration in forensic practice, the statistical analysis in paternity testing remains disputed. The Type 1 tri-allelic pattern generally results from somatic mutation in the early stage of individual development. The Type 2 tri-allelic pattern is commonly generated by segmental duplication in the genome. In this study, practical and theoretical aspects of the evaluation of evidence concerning the Type 1 and Type 2 tri-allelic patterns in healthy individuals are discussed based on the likelihood ratio (LR) in different categories of kinship cases. The calculation of the PI value concerning tri-allelic genotypes is formulated according to the generation and genetic transmission of tri-allelic patterns. Meanwhile, a package tool named TriPI is developed to assist the calculation of the PI value in paternity testing concerning tri-allelic subjects, which could benefit the evaluation of the weight of evidence in the interpretation of tri-allelic pattern in forensic practice.
Details
1 Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
2 Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory of Crime Scene Evidence, Institute of Criminal Science and Technology, Shanghai Municipal Public Security Bureau, Shanghai 200083, China
3 Shanghai Key Laboratory of Forensic Medicine, Academy of Forensic Science, Ministry of Justice, Shanghai 200063, China
4 Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China