Telomeres and P-element of Drosophila melanogaster contain sequences that replicate autonomously in Saccharomyces cerevisiae

Long telomeres in the polytene chromosomes of Drosophila melanogaster are associated with amplification of subtelomeric repeat sequences

“…They belong to the He-T family of sequences found in the telomeric and heterochromatic regions of the genome (Young et al, 1983;Traverse and Pardue, 1989;Biessmann et al n 1990; Levis, personal communication). The fragment Dm665 (Danilevskaya et al, 1984), which is a member of the He-T family of repetitive sequences, is located in the Y chromosome and shares homology with sequences located in subtelomeric regions (Danilevskaya et al, 1984;and unpublished observations). The telomere-associated sequences also frequently contain mobile elements of various kinds (Danilevskaya, unpublished observations Traverse and Pardue (1988) and Biessmann et al (1990) have described the de novo addition of He-T family sequences to the tips of broken chromosomes.…”

“…The DNA probes were labeled with tritiated thymidine by nick translation. The 2.4-kb Dm665 fragment was obtained by subcloning the Dm665 HindIII fragment from plasmid p665 into pBR322 (Danilevskaya et al, 1984 In situ hybridization of larval salivary gland polytene chromosomes from different T-32 sublines with telomere-associated probes Polytene chromosomes from the 6 sublines with morphologically different telomeres were subjected to in situ hybridization with 2 probes containing sequences homologous to the subtelomeric repeat designated Dm665 (Danilevskaya et al, 1984 (figs 1, 6). Note that these sublines also exhibit some hybridization with the 3L telomere, which is unlabeled in the other sublines.…”

“…The morphological peculiarities of telomeres can persist for a number of generations and serve as cytological markers in certain wildtype stocks (Lapta and Shakhbazov, 1986 (Danilevskaya et al, 1984). The Dm665 fragment is an AT-rich repeated sequence found at the tips of chromosomes and in heterochromatin, particularly in the Y chromosome.…”

Long telomeres in the polytene chromosomes of Drosophila melanogaster are associated with amplification of subtelomeric repeat sequences

“…The DNA probes were labeled with tritiated thymidine by nick translation. The 2.4-kb Dm665 fragment was obtained by subcloning the Dm665 HindIII fragment from plasmid p665 into pBR322 (Danilevskaya et al, 1984). A larger fragment homologous to Dm665 was obtained from a 10.5-kb insert in bacteriophage A 17.…”

“…This hypothesis was examined using the cloned DNA fragment Dm665 and the 10.5-kb insert of the phage A 17, which contains Dm665 and 2 copies of the transposable element hoppel (Danilevskaya et al, 1984). The Dm665 fragment is an AT-rich repeated sequence found at the tips of chromosomes and in heterochromatin, particularly in the Y chromosome.…”