A method for characterization of DNA samples of individuals for forensic purposes, based on sequence variations within the repeating units of variable number tandem repeats (VNTRs). PCR primers are designed for a common flanking region and each of the variant repeating units; the latter primers are initially used in low enough concentration so that on average only one binds per template; thus upon amplification and electrophoresis, a ladder is produced for each primer pair that indicates the position of the variant along the length of the VNTR. The sequence of the variants derived from ladders for all primer pairs is subject to great diversity, and is both characteristic of an individual and capable of digitalization for data storage, search and retrieval.