In this figure, all of the human chromosomes in this 'metaphase spread' were uniformly stained with a fluorescent dye. Then they were hybridized with simple-sequence DNA labeled with a fluorescent reporter molecule called biotin, which appears as a yellow band on chromosome 16, thus locating this particular simple sequence to one site in the genome. Even small differences in the total lengths of various minisatellites from different individuals can be detected. The differences provide the molecular basis of DNA fingerprinting. Red letters indicate positions where base differences were detected among the ten sequences.
Red dot indicates a base deletion.
It is different from simple sequence repeat regions, which can are about 100 kb long. Human DNA fingerprints. Functional DNA rearrangements represent a mechanism for regulation of gene expression of a small number of genes, but the consequences of this kind of regulation can be very important. Salmonella typhimurium is a pathogenic bacterium causing food poisoning. Two different types of proteins that assemble into bacterial flagella can be produced by Salmonella , but only one gene is expressed at a time.