Hypervariable sequences and DNA fingerprinting

The most polymorphic loci known in the human genome are tandemly repeated minisatellites (MS) and microsatellites (MCS), hundreds of which have been described and mapped. Jeffreys and his colleagues (Jeffreys, Wilson & Thein, 1985) were the first to show that probes derived from the human myoglobin gene (probes 33.6 and 33.15) could hybridize to several minisatellite loci, producing complex and individual-specific banding patterns called ‘DNA fingerprints’. Many other multilocus and single-locus probes have since been described (see Pena & Chakraborty, 1994). Fig. 4.1 shows an example of DNA fingerprints obtained with a multilocus probe, M13 phage DNA, which was independently discovered by Vassart et al. in Belgium (Vassart et al., 1987) and by Ryskov et al. in Russia (Jincharadze, Ivanov & Ryskov, 1987; Ryskov et al., 1988). This probe contains a minisatellite (M13-ms) which consists of repeating 15 bp sequences GAGGGTGGXGGXTCT. It detects a set of hypervariable regions in human DNA and makes it possible to estimate individual specificity as well as to establish paternity relationships. Ryskov et al. (1988) tested M13-ms for hybridization with DNA from many species and demonstrated a wide distribution of this MS in different taxonomic groups including man, animals, plants, bacteria. This peculiar characteristic of M13-ms allows one to apply its analysis for studying genomic diversity in different species.