Suppose the genotypes for parental cells have already been determined by a recognized repository (ATCC, DSMZ, or JCRB). In that case, the genotype of the submitted cells can be compared to genotypes in the database. Comparison of the genetic profile of the sample generated by short tandem repeat analysis (STR) to the cell line's known profile allows verification of the cell line's authenticity. The diversity of alleles, repeating segments of DNA 2 to 6 base pairs in length that have a diverse number of repeats at a single locus, makes it possible to generate unique genetic profiles by combining analysis results for several marker loci. For gender determination, the amelogenin marker found on the X and Y chromosome is routinely used.