Analysis of chromosome termini in potato varieties

Chromosomes of potato (Solanum tuberosum) are terminated by telomeres, which are formed by tandemly repeated [TTTAGGG]n oligonucleotide sequence. The total length of blocks of telomeric DNA has been known to vary largely among plant species and their varieties, and also among individual chromosome arms within a single nucleus. To check for such differences in potato varieties, which could be of a possible use in genotyping, we performed pulsed-field gel electrophoretic analysis of terminal restriction fragments in selected potato varieties. We found a typical range of telomere lengths of 20–60 kb in most analysed varieties. In one of analysed varieties (Monalisa), telomeres of wider span (up to 80 kb) have been observed. Most of restriction enzymes (PvuII, HaeIII, TaqI) produced a resulting smeared hybridisation pattern of telomeres. When using BglII, however, a doublet hybridisation band could be observed. This may reflect differences in composition of telomere-associated sequences at different chromosome ends.