biostudies-literatureUnknown11Zhou YNational Natural Science Foundation of ChinaBecause of its non-template addition feature, <i>Taq</i> DNA polymerase can catalyze one or more extra nucleotides onto the 3' terminus of PCR products. An extra peak is observed at DYS391 locus after the PCR products stored for 4 days at 4°C. To explore the formation mechanism of this artifact, PCR primers and amplicon sequences of Y-STR loci are analyzed, furthermore, PCR products storage conditions and termination of PCR are discussed. The extra peak is a + 2 addition product, which we call excessive addition split peak (EASP). The most significant difference between EASP and the incomplete addition of adenine product is that the size of EASP is about one base larger than the true allele, and the EASP locates on the right side of the real allelic peak. The EASP cannot be eliminated by iFrontiers in bioengineering and biotechnology1180542https://www.ebi.ac.uk/biostudies/studies/S-EPMC10174434biostudies-literatureExcessive addition split peak formed by the non-templated nucleotide addition property of <i>Taq</i> DNA polymerase after PCR amplification.PMC10174434Wu BTian TZhou YBo FZhu BfalseExcessive addition split peak formed by the non-templated nucleotide addition property of <i>Taq</i> DNA polymerase after PCR amplification.Because of its non-template addition feature, <i>Taq</i> DNA polymerase can catalyze one or more extra nucleotides onto the 3' terminus of PCR products. An extra peak is observed at DYS391 locus after the PCR products stored for 4 days at 4°C. To explore the formation mechanism of this artifact, PCR primers and amplicon sequences of Y-STR loci are analyzed, furthermore, PCR products storage conditions and termination of PCR are discussed. The extra peak is a + 2 addition product, which we call excessive addition split peak (EASP). The most significant difference between EASP and the incomplete addition of adenine product is that the size of EASP is about one base larger than the true allele, and the EASP locates on the right side of the real allelic peak. The EASP cannot be eliminated by i2023-01-01T00:00:00Z20232026-04-08T12:22:36.671Z2025-04-05T21:09:14.997ZS-EPMC101744343718004410.3389/fbioe.2023.1180542