Abstract: It has been a problem that the identification of genomic DNA by restriction fragment length polymorphisms is limited, owing to the low level of genetic variation ordinarily detectable by cloned DNA in this method. The invention provides for improved identification by making use of the existence of DNA regions of hypervariability, otherwise called minisatellite regions in which the DNA contains tandem repeats or quasi-block copolymer sequences and the number of repeats or copolymer units varies considerably from one individual to another. It has now been found that many such regions can be probed simultaneously in such a way as to display this variability using a DNA or other polynucleotide probe of which the essential constituent is a short core sequence tandemly repeated at least 3 and preferably at least 10 times.

Abstract: Test samples of genomic DNA may be characterized by the use of polynucleotide probes each of which is specific for an informative genetic locus. Such probes may be prepared by the use of probes which are capable of differentiating DNA by reference to more than one polymorphic minisatellite region or hypervariable locus. The polynucleotides and probes of the invention are of use for genetic identification purposes, paternity and maternity testing and particularly in forensic medicine.