Regional localisation of tri- and tetranucleotide repeat sequence-containing cosmids on chromosome 13.

A human chromosome 13-specific cosmid library has been screened with oligonucleotides containing tri- and tetranucleotide repeats with motifs: GACA, GACT, CAC, TCC. 20 cosmid clones were identified and their physical location on chromosome 13 was determined using fluorescence in situ hybridisation. Over 80% of the cosmids were detected using tetranucleotide repeats of which 50% were GACT, but these were distributed along the length of the chromosome. Clones from the 13q12-->q14 and 13q32-->q34 regions were apparently overrepresented and 10% of cosmids were localised to the short arm of the chromosome. These simple tandem repeats will be an important addition to the genetic mapping strategy for human chromosome 13.