Calculation of the Paternity Index for STR with tri-allelic patterns in paternity testing. (July 2021)

• Record Type: Journal Article
• Authors: Yang, Qinrui; Yao, Yining; Shao, Chengchen; Zhou, Yuxiang; Li, Hui; Li, Chengtao; Tang, Qiqun; Xie, Jianhui
• Is Part Of: Forensic science international. Volume 324(2021)
• Publication Date: 2021-07
• Subjects: Tri-allelic pattern -- Paternity testing -- Personal identification -- Biostatistics; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2021.110832
• Languages: English
• ISSNs: 0379-0738

Abstract

Highlights: The statistical interpretation of the Type 1 and Type 2 tri-allelic pattern in paternity testing is proposed. General equations for the Type 1 and Type 2 tri-allelic pattern related paternity cases is suggested. An Excel macro-enable TriPI package tool is provided to the calculation of paternity index concerning tri-allelic genotypes. 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.