Telomeres are the specialized structures at the ends of eukaryotic chromosomes and are composed of short T/G-rich DNA repeats and the proteins that interact with them. Internal to telomeres are subtelomeric regions that are species-specific and often repetitive. The yeast Kluyveromyces lactis has telomeric tracts of 10-20 copies of a 25-bp repeat, but the subtelomeric regions have not previously been characterized in detail. Here we have cloned and characterized subtelomeric regions from ten of the twelve chromosome ends. The amount of sequence examined ranged 0.7-10 kb for each subtelomeric region. We have identified a K. lactis subtelomeric element, the R element, which has a purine/pyrimidine strand bias and extends for about 2 kb. Internal to the R element, we found extensive homology among half of the chromosome ends reported here. This homology appears to include three putative gene families.
