Abstract: A method for the detection of diagnostic base sequences in a sample nucleic acid comprises contacting the sample in the presence of appropriate nucleoside triphosphates and an agent for polymerization thereof with a diagnostic primer for the diagnostic base sequence, the primer having a tail sequence comprising a tag region and a detector region such that an extension product of the primer is synthesized when the corresponding base sequence is present in the sample, and any extension product of the diagnostic primer acting as a template for extension of a further primer which hybridizes to a locus at a distance from the diagnostic base sequence. The sample is contacted with a tag primer which selectively hybridizes to the complement of the tag sequence in an extension product of the further primer and is extended, and the presence or absence of the diagnostic base sequence is detected by reference to the detector region in the further primer extension product.

Abstract: The present invention relates generally to a method of characterizing a sample of genomic DNA and to nucleotide sequences employed in the method as well as kits comprising these. In particular the invention involves the use of primers which selectively prime specific type(s) of internal repeat unit in a tandemly repeated region. The method of the invention is particularly useful in forensic or paternity studies and provides individual sample codes suitable for computerized storage on, and retrieval from, a database.