Construction of a library of cloned short tandem repeat (STR) alleles as universal templates for allelic ladder preparation

•We constructed a library of cloned short tandem repeat alleles.•The library covers 261 alleles for 22 STR loci and Amelogenin.•The plasmids bear long flanking sequences on both sides of core repeats.•The library could provide universal templates for allelic ladder preparation.•102 unreported repeat structures from 15 STR loci were described.