Chromosomal distribution of telomeric and telomeric-associated sequences in Hordeum chilense by in situ hybridization.

The chromosomal distribution of telomeric repeat pAtT4 from Arabidopsis thaliana and telomeric associated repetitive sequence HvT01 from Hordeum vulgare have been studied by FISH (fluorescence in situ hybridization) in two accessions (H1 and H7) of Hordeum chilense. The telomeric sequence pAtT4 is present at the end of all chromosome arms in H1 and H7 accessions. In contrast, the telomeric associated sequence homologous to HvT01 showed variability for size, intensity and position of the signals for each line. In H1, HvT01 was present in every chromosome whereas only four chromosomes were labeled in H7 accession. Physical distribution of GAA-satellite sequence on both H1 and H7 metaphase chromosomes was also studied. Polymorphism for hybridization signals between the two accessions for GAA-banding pattern was also found. Based on differences in position and intensity of the hybridization signals found for both GAA and HvT01-homologous sequences, karyotypes for the in situ hybridization patterns are presented for H1 and H7 accessions of H. chilense.