Master of Science in Forensic Science Program Director Dr. Fabio Oldoni, along with his collaborators, recently published “Massively parallel sequencing of 74 microhaplotypes for relationship testing in U.S. populations” in the journal “Forensic Science International Genetics.” The manuscript details their previously developed 74-locus Ion AmpliSeq™ microhaplotype (MH) panel for kinship testing across four major U.S. populations, including African American, European American, Southwest Hispanic, and East Asian American. The study analyzed 372 family samples using massively parallel sequencing (MPS) on the Ion GeneStudio S5 platform.

Microhaplotypes are short DNA regions containing multiple single-nucleotide polymorphisms (SNPs), which offer several advantages over traditional short tandem repeats (STRs), including lower mutation rates, no stutter artifacts, shorter amplicon lengths, and greater compatibility with MPS, which makes them particularly useful for degraded or mixed DNA samples.

The authors compared the performance of 74 MH loci with a 29-STR fragment panel using Familias software and calculated likelihood ratios (LRs) for different familial relationships, including parent–child, full siblings, half-siblings, and cousins. The results showed that the 74 MH panel outperformed the STR panel for first-degree relationships (parent–child and full siblings), producing higher and more tightly clustered logarithmic LR values. Both marker systems had difficulty distinguishing half-siblings, though MHs yielded stronger results than STRs; neither MHs nor STRs reliably differentiated cousins.

“The 74 MH panel demonstrates enhanced discriminatory power for close kinship testing,” said Oldoni. “However, the study also emphasizes the need for larger MH panels to improve resolution for more distant familial relationships, as well as highlights both the importance and potential of sequencing innovative and alternative MH markers in order to distinguish close and distant family relationships.”