Background: Genetic markers are routinely used in human identification of paternity, maternity, and kinship cases. We describe a DNA paternity case with one mismatch on SE33 locus between the alleged father (AF) and the child (daughter). Because there was a father-daughter relationship to solve this case we used chromosome X-STRs markers too.
Methods: As reference samples we used saliva collected from inside the cheek of each person using buccal swabs (Copan, Italy). The DNA samples were quantified on a 7500 ABI real-time PCR using the Investigator Quantiplex Pro Kit (Qiagen, Germany). Salivary DNA samples were amplified on a ProFlex PCR System (ThermoFischer, USA) using the multiplex STR markers from the AmpF/STR® NGM Select PCR Amplification Kit (Thermo-Fischer, USA) and Investigator® Argus X-12 QS kit markers (Qiagen, Germany). PCR products were run on capillary electrophoresis on an ABI 3500 Genetic Analyzer (ThermoFischer, USA).
Results: The AF was excluded from paternity on STRs markers due to one mismatch on SE33 locus. To confirm or exclude the paternity, we used the chromosome X-STRs markers, obtaining a perfect match between the AF and his daughter.
Conclusions: In paternity testing, where one or two mismatches are present between the child (daughter) and the AF on different loci on STR markers, the use of chromosome X-STRs is needed for the confirmation or exclusion of paternity.