Simple human DNA-repeats associated with genomic hypervariability, flanking the genomic retroposons and similar to retroviral sites.

Earlier we found a human hypervariable genomic region (GVR). The DNA hybridization probe isolated from this region detects multiple hypervariability of restriction DNA fragments from genomic loci. The sequencing data suggest that the genomic instability and variability are associated with tandem DNA repeats. The DNA hybridization probe contains two families of simple DNA repeats designated as 'apo' and 'tau'. The (TC)n-rich family of DNA 'tau'-repeats bears some similarity to the simple transcribed repeats of Drosophila virilis, simple repetitive motifs of the human proenkephaline gene exon 1, and short sites of retroviral LTR ends. Apo-repeats show an unusual similarity to Rauscher viral env gene site. Besides GVR, apo- and tau-like repeats are localized in other genomic loci and can form separate tandem clusters and terminal repeats flanking certain copies of retroposons (Alu-SINES).