Destabilization of Simple Repetitive DNA Sequences by Transcription in Yeast

Simple repetitive DNA sequences in the eukaryotic genome frequently alter in length. In wild-type strains, we find that transcription through a repetitive poly GT tract destabilizes the tract four- to ninefold. In mismatch repair-deficient yeast strains, simple repeats are very unstable. High levels of transcription in such strains destabilize repetitive tracts an additional two- to threefold.