[Amplification of subtelomeric sequences in "long" telomers of Drosophila melanogaster polytene chromosomes]

Drosophila melanogaster heat-resistant stock T32 is characterized by additional chromatin in the telomeres of the X and 2L chromosomes. Moreover, elevated (32 degrees C) temperature provokes high instability in the telomere morphology, so that sublines can be obtained which have additional chromatin in different chromosomes. Morphological patterns of telomeres in each subline are stable, if flies are kept at 23 degrees C. It was demonstrated using this model that additional chromatin in the "long" telomeres hybridizes actively with 3H-labelled telomere-associated Dm665 probe. The "short" telomeres show far weaker hybridization, if any, with Dm665. This means that morphological changes in the telomeres of polytene chromosomes result from different degree amplification of the telomere-associated sequences.