ISOLATION OF HUMAN SIMPLE REPEAT LOCI BY HYBRIDIZATION SELECTION

We have isolated short tandem repeat arrays from the human genome, usi ng a rapid method involving filter hybridization to enrich for tri- or tetranucleotide tandem repeats. About 30% of clones from the enriched library cross-hybridize with probes containing trimeric or tetrameric tandem arrays, facilitating the rapid isolation of large numbers of c lones. In an initial analysis of 54 clones, 46 different tandem arrays were identified. Analysis of these tandem repeat loci by PCR showed t hat 24 were polymorphic in length; substantially higher levels of poly morphism were displayed by the tetrameric repeat loci isolated than by the trimeric repeats. Primary mapping of these loci by linkage analys is showed that they derive from 17 chromosomes, including the X chromo some. We anticipate the use of this strategy for the efficient isolati on of tandem repeats from other sources of genomic DNA, including DNA from flow-sorted chromosomes, and from other species.