A "high-resolution, two-dimensional Southern transfer" method has been developed and was used to examine the distribution of a class of interspersed repeated sequences in human genomes. This method consists of two separate restriction enzyme digestions, including an in situ digestion, and two-dimensional electrophoresis using a large-sized agarose gel. The first 163-base-pair region of the human LINE-1 full-length sequence was used to probe human genomic DNA from placental tissue samples. About 900 LINE-1 signals were resolved from each DNA sample within a 2-D plane. The bulk of the fragments were between 0.5 to 23 kilobases in length. At a minimum 15 variant signals were detected between DNA samples from male and female individuals and at a minimum 16 variant signals were detected between two different female samples. This approach can potentially be used to perform high-resolution human genome fingerprinting analyses.