Abstract
A routine paternity test using 23 autosomal short tandem repeats (A-STRs) revealed three Mendelian inconsistencies at D21S11, D13S317, and D7S820 between the alleged father and child, yielding a combined paternity index (CPI) below the confirmation threshold (CPI > 10⁴) stipulated in the Chinese technical specifications. Extended capillary electrophoresis typing of 48 A-STRs and 17 Y-STRs eliminated further mismatches and raised the CPI above the standard. Subsequent massively parallel sequencing (MPS) of 54 A-STRs, 27 X-STRs, 48 Y-STRs, 132 identity-informative single nucleotide polymorphisms (iiSNPs), and mitochondrial DNA (mtDNA) provided both length- and sequence-based genotypes. The CPI reached 2.78 × 10²¹ (A-STRs) and 6.28 × 10¹⁷ (iiSNPs), strongly supporting the paternity. All other marker systems were consistent with the alleged relationships. The three observed incompatibilities were attributed to single-step paternal mutations. This case highlights the risk of misinterpreting multi-locus STR mismatches and demonstrates the value of MPS-based genotyping in resolving complex paternity evaluations.
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This research was funded by the National Key R&D Program of China (Grant No. 2024YFC3306702) and the High-level Talent Research Start-up Fund of Guiyang Kangyang University (No. K2026-010) .
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This research was funded by the National Key R&D Program of China (Grant No. 2024YFC3306702) and the High-level Talent Research Start-up Fund of Guiyang Kangyang University (No. K2026-010).
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All experimental processes in this study strictly followed ethical research principles, and all methods were performed in accordance with the relevant guidelines and regulations. All samples were collected after obtaining informed consent. This study was approved by the Ethics Committee of Sun Yat-sen University (approval number: No. 008 [2016]).
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Wang, N., Chen, W., Chen, J. et al. Reinvestigation of a paternity case with three CODIS core STR inconsistencies using MPS-based multi‑marker analysis. Sci Rep (2026). https://doi.org/10.1038/s41598-026-53806-8
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DOI: https://doi.org/10.1038/s41598-026-53806-8
