Less is more--length reduction of STR amplicons using redesigned primers.

PCR primers closely flanking the repeat region were redesigned to reduce the amplicon length of the selected STRs down to approximately 100 bp for the shorter alleles (loci HumTH01, D10S2325, DYS19 and DYS391). Highly degraded DNA (e.g. formalin-fixed tissue) and very low amounts of DNA could be more successfully typed using the new redesigned primers compared to the established sequences generating longer amplicons.