scholarly journals Do Time, Heterochromatin, NORs, or Chromosomal Rearrangements Correlate with Distribution of Interstitial Telomeric Repeats in Sigmodon (Cotton Rats)?

2012 ◽  
Vol 103 (4) ◽  
pp. 493-502 ◽  
Author(s):  
V. J. Swier ◽  
F. A. Anwarali Khan ◽  
R. J. Baker
Keyword(s):  
Chromosomal Rearrangements ◽  
Telomeric Repeats ◽  
Cotton Rats ◽  
Interstitial Telomeric Repeats

scholarly journals Cytogenetic Analysis Did Not Reveal Differentiated Sex Chromosomes in Ten Species of Boas and Pythons (Reptilia: Serpentes)

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 934 ◽  
Author(s):  
Augstenová ◽  
Mazzoleni ◽  
Kostmann ◽  
Altmanová ◽  
Frynta ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Sex Chromosomes ◽  
Chromosomal Rearrangements ◽  
Telomeric Repeats ◽  
Molecular Cytogenetic ◽  
Poorly Differentiated ◽  
Python Bivittatus ◽  
Interstitial Telomeric Repeats ◽  
Cytogenetic Methods

Homologous and differentiated ZZ/ZW sex chromosomes (or derived multiple neo-sex chromosomes) were often described in caenophidian snakes, but sex chromosomes were unknown until recently in non-caenophidian snakes. Previous studies revealed that two species of boas (Boa imperator, B. constrictor) and one species of python (Python bivittatus) independently evolved XX/XY sex chromosomes. In addition, heteromorphic ZZ/ZW sex chromosomes were recently revealed in the Madagascar boa (Acrantophis sp. cf. dumerili) and putatively also in the blind snake Myriopholis macrorhyncha. Since the evolution of sex chromosomes in non-caenophidian snakes seems to be more complex than previously thought, we examined ten species of pythons and boas representing the families Boidae, Calabariidae, Candoiidae, Charinidae, Pythonidae, and Sanziniidae by conventional and molecular cytogenetic methods, aiming to reveal their sex chromosomes. Our results show that all examined species do not possess sex-specific differences in their genomes detectable by the applied cytogenetic methods, indicating the presence of poorly differentiated sex chromosomes or even the absence of sex chromosomes. Interestingly, fluorescence in situ hybridization with telomeric repeats revealed extensive distribution of interstitial telomeric repeats in eight species, which are likely a consequence of intra-chromosomal rearrangements.

scholarly journals Interstitial Telomeric Repeats Are Rare in Turtles

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 657 ◽  
Author(s):  
Lorenzo Clemente ◽  
Sofia Mazzoleni ◽  
Eleonora Pensabene Bellavia ◽  
Barbora Augstenová ◽  
Markus Auer ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Karyotype Evolution ◽  
Chromosomal Rearrangements ◽  
Telomeric Repeats ◽  
Squamate Reptiles ◽  
Nucleoprotein Complexes ◽  
Interstitial Telomeric Repeats ◽  
Eukaryotic Organisms ◽  
Genomic Regions

Telomeres are nucleoprotein complexes protecting chromosome ends in most eukaryotic organisms. In addition to chromosome ends, telomeric-like motifs can be accumulated in centromeric, pericentromeric and intermediate (i.e., between centromeres and telomeres) positions as so-called interstitial telomeric repeats (ITRs). We mapped the distribution of (TTAGGG)n repeats in the karyotypes of 30 species from nine families of turtles using fluorescence in situ hybridization. All examined species showed the expected terminal topology of telomeric motifs at the edges of chromosomes. We detected ITRs in only five species from three families. Combining our and literature data, we inferred seven independent origins of ITRs among turtles. ITRs occurred in turtles in centromeric positions, often in several chromosomal pairs, in a given species. Their distribution does not correspond directly to interchromosomal rearrangements. Our findings support that centromeres and non-recombining parts of sex chromosomes are very dynamic genomic regions, even in turtles, a group generally thought to be slowly evolving. However, in contrast to squamate reptiles (lizards and snakes), where ITRs were found in more than half of the examined species, and birds, the presence of ITRs is generally rare in turtles, which agrees with the expected low rates of chromosomal rearrangements and rather slow karyotype evolution in this group.

scholarly journals Interstitial telomeric repeats-associated DNA breaks

Nucleus ◽  
2017 ◽  
Vol 8 (6) ◽  
pp. 641-653 ◽  
Author(s):  
Olga Shubernetskaya ◽  
Dmitry Skvortsov ◽  
Sergey Evfratov ◽  
Maria Rubtsova ◽  
Elena Belova ◽  
...  
Keyword(s):  
Dna Breaks ◽  
Telomeric Repeats ◽  
Interstitial Telomeric Repeats

Interstitial telomeric repeats are enriched in the centromeres of chromosomes in Solanum species

2012 ◽  
Vol 21 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Li He ◽  
Jun Liu ◽  
Giovana A. Torres ◽  
Haiqin Zhang ◽  
Jiming Jiang ◽  
...  
Keyword(s):  
Solanum Species ◽  
Telomeric Repeats ◽  
Interstitial Telomeric Repeats

scholarly journals Histone H1 protects telomeric repeats from H3K27me3 invasion in Arabidopsis

2020 ◽  
Author(s):  
Gianluca Teano ◽  
Lorenzo Concia ◽  
Léopold Carron ◽  
Léa Wolff ◽  
Kateřina Adamusová ◽  
...  
Keyword(s):  
Dna Binding ◽  
Long Distance ◽  
Telomeric Repeats ◽  
Protein Coding ◽  
Telomere Repeat ◽  
Linker Histones ◽  
Chromatin Compaction ◽  
Protein Coding Genes ◽  
Distance Effects ◽  
Interstitial Telomeric Repeats

AbstractLinker histones play a pivotal role in shaping chromatin architecture, notably through their globular H1 (GH1) domain that contacts the nucleosome and linker DNA. Yet, the interplay of H1 with chromatin factors along the epigenome landscape is poorly understood. Here, we report that Arabidopsis H1 favors chromatin compaction and H3K27me3 marking on a majority of Polycomb-targeted protein-coding genes while preventing H3K27me3 accumulation on telomeres and pericentromeric interstitial telomeric repeats (ITRs). These contrasting effects of H1 on H3K27me3 enrichment are associated with long-distance effects on the 3D organization of telomeres and ITRs. Mechanistically, H1 prevents ITRs from being invaded by Telomere Repeat Binding 1 (TRB1), a GH1-containing telomere component with an extra-telomeric function in targeting Polycomb to genes bearing telomeric motifs. We propose that reciprocal DNA binding of H1 and TRB1 to clustered telobox motifs prevents H3K27me3 accumulation on large chromosomal blocks, conferring a sequence-specific role to H1 in epigenome homeostasis.

Extensive Amplification of Telomeric Repeats in the Karyotypically Highly Diverse African Pygmy Mice

2017 ◽  
Vol 152 (2) ◽  
pp. 55-64 ◽  
Author(s):  
Victor Colomina ◽  
Josette Catalan ◽  
Janice Britton-Davidian ◽  
Frédéric Veyrunes
Keyword(s):  
Mammalian Species ◽  
Chromosomal Rearrangements ◽  
Replication Timing ◽  
Pericentromeric Region ◽  
Chromosomal Evolution ◽  
Telomeric Repeats ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Karyotypic Diversity ◽  
The One

Telomeres are ribonucleoprotein structures protecting the physical ends of eukaryotic chromosomes. However, telomeric sequences can also occur at non-terminal regions of chromosomes, forming the so-called interstitial telomeric sequences (ITSs). Some ITSs are considered as relics of past chromosomal rearrangements and as such provide important insights into karyotype evolution. By FISH, we explored the distribution of telomeric motifs in the genome of a complex of mammalian species that has long been recognized for its extraordinary karyotypic diversity: the African pygmy mice. This survey involved 5 species, representing 10 highly diverse karyotypes with or without autosomal and sex-autosome robertsonian (Rb) fusions. The study revealed that in species with an ancestral-like karyotype (i.e., no fusions; Mus mattheyi and M. indutus), only terminal telomeres were observed, whereas in species experiencing intense chromosomal evolution (e.g., M. minutoides, M. musculoides), a large amplification of telomeric repeats was also identified in the pericentromeric region of acrocentrics and most metacentrics. We concluded that (i) the mechanism of Rb fusion in the African pygmy mice is different than the one highlighted in the house mouse; (ii) the intensity of the ITS hybridization signal could be a signature of the age of formation of the Rb fusion; (iii) the large amplification of pericentromeric telomeric sequences in acrocentrics may mediate the formation of Rb fusions, and (iv) the ITSs on the sex-autosome fusion Rb(X.1) may participate to the insulation buffer between the sexual and autosomal arms to prevent X inactivation from spreading and silencing autosomal genes and allow the independent regulation of replication timing of both segments.

Interstitial telomeric repeats are not preferentially involved in radiation-induced chromosome aberrations in human cells

2004 ◽  
Vol 104 (1-4) ◽  
pp. 123-130 ◽  
Author(s):  
C. Desmaze ◽  
L.M. Pirzio ◽  
R. Blaise ◽  
C. Mondello ◽  
E. Giulotto ◽  
...  
Keyword(s):  
Chromosome Aberrations ◽  
Human Cells ◽  
Telomeric Repeats ◽  
Radiation Induced ◽  
Interstitial Telomeric Repeats

scholarly journals Cytogenetic markers reveal a reinforcement of variation in the tension zone between chromosome races in the brachypterous grasshopper Podisma sapporensis Shir. on Hokkaido Island

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Beata Grzywacz ◽  
Haruki Tatsuta ◽  
Alexander G. Bugrov ◽  
Elżbieta Warchałowska-Śliwa
Keyword(s):  
Dna Sequences ◽  
Genome Instability ◽  
Significant Degree ◽  
Hybrid Population ◽  
Telomeric Dna ◽  
Telomeric Repeats ◽  
C Banding ◽  
Rdna Sequences ◽  
Rdna Sites ◽  
Interstitial Telomeric Repeats

AbstractThe cytogenetic characteristics of the grasshopper Podisma sapporensis (two races 2n = 23♂ X0/XX and 2n = 22♂ neo-XY/neo-XX) were analysed through fluorescence in situ hybridization with rDNA and telomeric DNA probes, C-banding, fluorochrome and silver staining. For the first time, samples from the neighbourhood of a hybrid population (i.e., Mikuni Pass population) were studied. Our results indicated a significant degree of chromosomal differentiation between P. sapporensis races when comparing the number and position of the rDNA sites, as well as the heterochromatin composition and distribution obtained by C-banding and DAPI/CMA3 staining. Telomeric signals were usually detected at the distal and/or subdistal position of the autosomes; however, some chromosome ends lacked signals, probably due to a low number of telomeric repeats. On the other hand, telomeric DNA sequences were found as interstitial telomeric repeats in some autosomes, which can trigger a variety of genome instability. B chromosomes were found in specimens belonging to both main races from nine out of 22 localities. Four types of X chromosomes in the X0/XX race were identified. It was concluded that the physical mapping of rDNA sequences and heterochromatin are useful as additional markers for understanding the phylogeographic patterns of cytogenetic differentiation in P. sapporensis populations.

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