Fig. 3. Maintenance of the T₂AG₃-only telomere. (A) Schematic representation of the modified VII-L telomere used to monitor the length of the wild type and of T₂AG₃-only telomere. A representation of the ura3-1 allele is shown to indicate the existence of a 753 nt fragment hybridizing with the ura3 probe. (B) Genomic DNA was digested with EcoRV and HindIII and hybridized with the ura3 probe. The median length of the telomeric restriction fragment was calculated using a set of molecular weight markers (not shown) and using the ura3-1 753 nt fragment as an internal control. 720 bp was subtracted from this value to give the size of the distal TG_1–3 repeats (Y strains) or the distal T₂AG₃ repeats (Hy strains). wt: wild type for the RAP1, RIF1, RIF2 and TEL1 genes.