The occurrence of different cleavage sites for restriction enzymes in the DNA of different individuals of the same species. Cleavage of DNA from different individuals with restriction enzymes thus produces differing sets of restriction fragments. The deletion of existing restriction sites or the creation of new ones is the result of random base changes in the noncoding stretches of DNA (introns) between genes. RFLPs have provided geneticists with a powerful set of genetic markers for mapping the genome (see restriction mapping), for identifying particular genes and mutations (see gene tracking), and for characterizing organisms (see DNA fingerprinting; ribotyping).