A landmark in the base sequence of a genome used for placing partial sequences in correct relation to each other; especially as a strategy for co-ordination of the efforts of many laboratories in sequencing the human genome. Originally, the use of defined PCR primers allowed the examination of DNA for the ability to generate a 200-500 bp amplicon which indicated the presence of the STS. With the growth of banked genome data, electronic PCR (e-PCR), the automated search of databases for STSs as DNA sequences of the desired size and orientation and bracketed by sites complementary to the defining primers, is possible as a non-laboratory, entirely computer based procedure