Comparative analysis of telomeric heterochromatin of rye chromosomes in rye and triticale by fish

The repetitive DNA composition in the telomeres of rye chromosomes in two rye lines and three triticale varieties is carried out using a sensitive sequential and successive fluorescence in situ hybridization (FISH). The rye lines: 'Petkus', and 'Imperial', and the 6x-triticale lines: 'Badiel', Tajuna' and '0-22-80', were comparatively investigated. Repetitive DNA sequences of 120 bp, 480 bp and 610 bp from rye were studied. The 5S rDNA sequence from wheat was used to identify the metacentric chromosomes. Interstitial hybridization sites detected correspond to only one sequence 120 bp or 480 bp. Concerning the telomeric repetitive DNA sequences our results demonstrate: i) the high polymorphism that exits for the composition and arrangement in the telomeres of open-pollination rye lines; and, ii) the complex organization in the telomeres of rye chromosomes in triticale. These consist of arrays of multiple family sequences. The number and order of repeated sequences varied between and within varieties.