A brief historical perspective on STR marker selection notes that STR markers were first described as effective tools for human identity testing in the early 1990s. Because of their use in the U.S. National DNA Database (NDNAD) as well as other criminal justice databases around the world, these STR loci dominate the genetic information collected to date on human beings. The creation of commercial STR kits has been historically driven by the selection of loci that have become part of NDNADs; however, in some cases loci were selected for inclusion in databases because of the ones available in commercial kits or already in use for forensic casework. The Human Genome Project officially was completed successfully in April 2003, when it announced a "finished" reference sequence of the human genome. The finished sequence continues to be refined, however, and there are several compilations that differ from one another. A discussion of population variation addresses allele range and variants, the characterizing of a variant allele that occurs between two loci, null alleles with commercial STR kits, and mutation rates. A brief review of population studies is followed by summary descriptions of Web resources. Other sections of the paper discuss potential linkage to disease genes, probabilistic predictions of sample ethnicity, additional STRs beyond the current core loci, and Y-chromosome STR loci. 9 tables and 139 references