scholarly journals Chromosome Banding in Amphibia. XXXIV. Intrachromosomal Telomeric DNA Sequences in Anura

2016 ◽  
Vol 148 (2-3) ◽  
pp. 211-226 ◽  
Author(s):  
Michael Schmid ◽  
Claus Steinlein
Keyword(s):  
Dna Sequences ◽  
Distribution Patterns ◽  
Detailed Comparison ◽  
Telomeric Dna ◽  
Mitotic Chromosomes ◽  
Telomeric Sequences ◽  
Anuran Species ◽  
Specific Distribution ◽  
Large Clusters ◽  
Chromosome Regions

The mitotic chromosomes of 4 anuran species were examined by various classical banding techniques and by fluorescence in situ hybridization using a (TTAGGG)n repeat. Large intrachromosomal telomeric sequences (ITSs) were demonstrated in differing numbers and chromosome locations. A detailed comparison of the present results with numerous published and unpublished data allowed a consistent classification of the various categories of large ITSs present in the genomes of anurans and other vertebrates. The classification takes into consideration the total numbers of large ITSs in the karyotypes, their chromosomal locations and their specific distribution patterns. A new category of large ITSs was recognized to exist in anuran species. It consists of large clusters of ITSs located in euchromatic chromosome segments, which is in clear contrast to the large ITSs in heterochromatic chromosome regions known in vertebrates. The origin of the different categories of large ITSs in heterochromatic and euchromatic chromosome regions, their mode of distribution in the karyotypes and evolutionary fixation in the genomes, as well as their cytological detection are discussed.

scholarly journals Genomic in situ hybridization in interspecific hybrids of scallops (Bivalvia, Pectinidae) and localization of the satellite DNA Cf303, and the vertebrate telomeric sequences (TTAGGG)n on chromosomes of scallop Chlamys farreri (Jones & Preston, 1904)

2018 ◽  
Vol 12 (1) ◽  
pp. 83-95
Author(s):  
Liping Hu ◽  
Liming Jiang ◽  
Ke Bi ◽  
Huan Liao ◽  
Zujing Yang ◽  
...  
Keyword(s):  
Interspecific Hybrids ◽  
Distribution Patterns ◽  
Mitotic Chromosomes ◽  
Chromosomal Distribution ◽  
Satellite Dnas ◽  
Banding Patterns ◽  
Telomeric Sequences ◽  
Specific Distribution ◽  
Species Specific

Mitotic chromosome preparations of the interspecific hybrids Chlamysfarreri (Jones & Preston, 1904) × Patinopectenyessoensis (Jay, 1857), C.farreri × Argopectenirradinas (Lamarck, 1819) and C.farreri × Mimachlamysnobilis (Reeve, 1852) were used to compare two different scallop genomes in a single slide. Although genomic in situ hybridization (GISH) using genomic DNA from each scallop species as probe painted mitotic chromosomes of the interspecific hybrids, the painting results were not uniform; instead it showed species-specific distribution patterns of fluorescent signals among the chromosomes. The most prominent GISH-bands were mainly located at centromeric or telomeric regions of scallop chromosomes. In order to illustrate the sequence constitution of the GISH-bands, the satellite Cf303 sequences of C.farreri and the vertebrate telomeric (TTAGGG)n sequences were used to map mitotic chromosomes of C.farreri by fluorescence in situ hybridization (FISH). The results indicated that the GISH-banding pattern presented by the chromosomes of C.farreri is mainly due to the distribution of the satellite Cf303 DNA, therefore suggesting that the GISH-banding patterns found in the other three scallops could also be the result of the chromosomal distribution of other species-specific satellite DNAs.

scholarly journals Telomeric DNA sequences in beetle taxa vary with species richness

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Prušáková ◽  
Vratislav Peska ◽  
Stano Pekár ◽  
Michal Bubeník ◽  
Lukáš Čížek ◽  
...  
Keyword(s):  
Species Richness ◽  
Dna Sequences ◽  
Genome Instability ◽  
Telomeric Sequence ◽  
Dna Repeats ◽  
Telomeric Dna ◽  
Common Pattern ◽  
Telomeric Sequences ◽  
Genomic Changes ◽  
Protective Structures

AbstractTelomeres are protective structures at the ends of eukaryotic chromosomes, and disruption of their nucleoprotein composition usually results in genome instability and cell death. Telomeric DNA sequences have generally been found to be exceptionally conserved in evolution, and the most common pattern of telomeric sequences across eukaryotes is (TxAyGz)n maintained by telomerase. However, telomerase-added DNA repeats in some insect taxa frequently vary, show unusual features, and can even be absent. It has been speculated about factors that might allow frequent changes in telomere composition in Insecta. Coleoptera (beetles) is the largest of all insect orders and based on previously available data, it seemed that the telomeric sequence of beetles varies to a great extent. We performed an extensive mapping of the (TTAGG)n sequence, the ancestral telomeric sequence in Insects, across the main branches of Coleoptera. Our study indicates that the (TTAGG)n sequence has been repeatedly or completely lost in more than half of the tested beetle superfamilies. Although the exact telomeric motif in most of the (TTAGG)n-negative beetles is unknown, we found that the (TTAGG)n sequence has been replaced by two alternative telomeric motifs, the (TCAGG)n and (TTAGGG)n, in at least three superfamilies of Coleoptera. The diversity of the telomeric motifs was positively related to the species richness of taxa, regardless of the age of the taxa. The presence/absence of the (TTAGG)n sequence highly varied within the Curculionoidea, Chrysomeloidea, and Staphylinoidea, which are the three most diverse superfamilies within Metazoa. Our data supports the hypothesis that telomere dysfunctions can initiate rapid genomic changes that lead to reproductive isolation and speciation.

Characterization of two telomeric DNA processing reactions in Saccharomyces cerevisiae

1988 ◽  
Vol 8 (11) ◽  
pp. 4642-4650
Author(s):  
A W Murray ◽  
T E Claus ◽  
J W Szostak
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Division ◽  
Dna Polymerase ◽  
Dna Sequences ◽  
Inverted Repeat ◽  
Telomeric Sequence ◽  
Telomeric Dna ◽  
Telomeric Sequences ◽  
Telomere Elongation

We have investigated two reactions that occur on telomeric sequences introduced into Saccharomyces cerevisiae cells by transformation. The elongation reaction added repeats of the yeast telomeric sequence C1-3A to telomeric sequences at the end of linear DNA molecules. The reaction worked on the Tetrahymena telomeric sequence C4A2 and also on the simple repeat CA. The reaction was orientation specific: it occurred only when the GT-rich strand ran 5' to 3' towards the end of the molecule. Telomere elongation occurred by non-template-directed DNA synthesis rather than any type of recombination with chromosomal telomeres, because C1-3A repeats could be added to unrelated DNA sequences between the CA-rich repeats and the terminus of the transforming DNA. The elongation reaction was very efficient, and we believe that it was responsible for maintaining an average telomere length despite incomplete replication by template-directed DNA polymerase. The resolution reaction processed a head-to-head inverted repeat of telomeric sequences into two new telomeres at a frequency of 10(-2) per cell division.

scholarly journals Tracking the Distribution and Burst of Nuclear Mitochondrial DNA Sequences (NUMTs) in Fig Wasp Genomes

Insects ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 680
Author(s):  
Jian-Xia Wang ◽  
Jing Liu ◽  
Yun-Heng Miao ◽  
Da-Wei Huang ◽  
Jin-Hua Xiao
Keyword(s):  
Mitochondrial Dna ◽  
Dna Sequences ◽  
Theoretical Basis ◽  
Nuclear Genome ◽  
Distribution Patterns ◽  
Good Evidence ◽  
Fig Wasp ◽  
Fig Wasps ◽  
Exogenous Dna ◽  
Specific Distribution

Mitochondrial DNA sequences can be transferred into the nuclear genome, giving rise to nuclear mitochondrial DNA sequences (NUMTs). NUMTs have been described in numerous eukaryotes. However, the studies on the distribution of NUMTs and its influencing factors are still inadequate and even controversial. Previous studies have suggested that Hymenoptera may be a group rich in NUMTs, in which we selected 11 species of fig wasps (Chalcidoidea, Hymenoptera) to analyze the distribution and evolution of NUMTs at the genomic level. The results showed that the contents of NUMTs varied greatly in these species, and bursts of NUMTs existed in some species or lineages. Further detailed analyses showed that the large number of NUMTs might be related to the large genomes; NUMTs tended to be inserted into unstable regions of the genomes; and the inserted NUMTs might also be affected by transposable elements (TEs) in the neighbors, leading to fragmentations and duplications, followed by bursts of NUMTs. In summary, our results suggest that a variety of genomic environmental factors can determine the insertion and post-insertion fate of NUMTs, resulting in their species- or lineage-specific distribution patterns, and that studying the evolution of NUMTs can provide good evidence and theoretical basis for exploring the dynamics of exogenous DNA entering into the nuclear genome.

scholarly journals Characterization of two telomeric DNA processing reactions in Saccharomyces cerevisiae.

1988 ◽  
Vol 8 (11) ◽  
pp. 4642-4650 ◽  
Author(s):  
A W Murray ◽  
T E Claus ◽  
J W Szostak
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Division ◽  
Dna Polymerase ◽  
Dna Sequences ◽  
Inverted Repeat ◽  
Telomeric Sequence ◽  
Telomeric Dna ◽  
Telomeric Sequences ◽  
Telomere Elongation

We have investigated two reactions that occur on telomeric sequences introduced into Saccharomyces cerevisiae cells by transformation. The elongation reaction added repeats of the yeast telomeric sequence C1-3A to telomeric sequences at the end of linear DNA molecules. The reaction worked on the Tetrahymena telomeric sequence C4A2 and also on the simple repeat CA. The reaction was orientation specific: it occurred only when the GT-rich strand ran 5' to 3' towards the end of the molecule. Telomere elongation occurred by non-template-directed DNA synthesis rather than any type of recombination with chromosomal telomeres, because C1-3A repeats could be added to unrelated DNA sequences between the CA-rich repeats and the terminus of the transforming DNA. The elongation reaction was very efficient, and we believe that it was responsible for maintaining an average telomere length despite incomplete replication by template-directed DNA polymerase. The resolution reaction processed a head-to-head inverted repeat of telomeric sequences into two new telomeres at a frequency of 10(-2) per cell division.

Distribution of Interstitial Telomeric Sequences in Primates and the Pygmy Tree Shrew (Scandentia)

2017 ◽  
Vol 151 (3) ◽  
pp. 141-150 ◽  
Author(s):  
Sofia Mazzoleni ◽  
Odessa Schillaci ◽  
Luca Sineo ◽  
Francesca Dumas
Keyword(s):  
Dna Sequences ◽  
Tree Shrew ◽  
Chromosomal Rearrangements ◽  
Primate Species ◽  
Telomeric Dna ◽  
Erythrocebus Patas ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Cercopithecus Petaurista ◽  
Almost All

It has been hypothesized that interstitial telomeric sequences (ITSs), i.e., repeated telomeric DNA sequences found at intrachromosomal sites in many vertebrates, could be correlated to chromosomal rearrangements and plasticity. To test this hypothesis, we hybridized a telomeric PNA probe through FISH on representative species of 2 primate infraorders, Strepsirrhini (Lemur catta, Otolemur garnettii, Nycticebus coucang) and Catarrhini (Erythrocebus patas, Cercopithecus petaurista, Chlorocebus aethiops, Colobus guereza), as well as on 1 species of the order Scandentia, Tupaia minor, used as an outgroup for primates in phylogenetic reconstructions. In almost all primate species analyzed, we found a telomeric pattern only. In Tupaia, the hybridization revealed many bright ITSs on at least 11 chromosome pairs, both biarmed and acrocentric. These ITS signals in Tupaia correspond to fusion points of ancestral human syntenic associations, but are also present in other chromosomes showing synteny to only a single human chromosome. This distribution pattern was compared to that of the heterochromatin regions detected through sequential C-banding performed after FISH. Our results in the analyzed species, compared with literature data on ITSs in primates, allowed us to discuss different mechanisms responsible for the origin and distribution of ITSs, supporting the correlation between rearrangements and ITSs.

scholarly journals TRF1 and TRF2 use different mechanisms to find telomeric DNA but share a novel mechanism to search for protein partners at telomeres

2013 ◽  
Vol 42 (4) ◽  
pp. 2493-2504 ◽  
Author(s):  
Jiangguo Lin ◽  
Preston Countryman ◽  
Noah Buncher ◽  
Parminder Kaur ◽  
Longjiang E ◽  
...  
Keyword(s):  
Single Molecule ◽  
Dna Sequences ◽  
Specific Binding ◽  
General Mechanism ◽  
Telomeric Dna ◽  
External Energy ◽  
Telomeric Sequences ◽  
Shelterin Complex ◽  
Protein Partners ◽  
A Genome

Abstract Human telomeres are maintained by the shelterin protein complex in which TRF1 and TRF2 bind directly to duplex telomeric DNA. How these proteins find telomeric sequences among a genome of billions of base pairs and how they find protein partners to form the shelterin complex remains uncertain. Using single-molecule fluorescence imaging of quantum dot-labeled TRF1 and TRF2, we study how these proteins locate TTAGGG repeats on DNA tightropes. By virtue of its basic domain TRF2 performs an extensive 1D search on nontelomeric DNA, whereas TRF1’s 1D search is limited. Unlike the stable and static associations observed for other proteins at specific binding sites, TRF proteins possess reduced binding stability marked by transient binding (∼9–17 s) and slow 1D diffusion on specific telomeric regions. These slow diffusion constants yield activation energy barriers to sliding ∼2.8–3.6 κBT greater than those for nontelomeric DNA. We propose that the TRF proteins use 1D sliding to find protein partners and assemble the shelterin complex, which in turn stabilizes the interaction with specific telomeric DNA. This ‘tag-team proofreading’ represents a more general mechanism to ensure a specific set of proteins interact with each other on long repetitive specific DNA sequences without requiring external energy sources.

Telomeric and interstitial telomeric-like DNA sequences in Orthoptera genomes

Genome ◽  
2004 ◽  
Vol 47 (4) ◽  
pp. 757-763 ◽  
Author(s):  
C López-Fernández ◽  
E Pradillo ◽  
M Zabal-Aguirre ◽  
J L Fernández ◽  
C García de la Vega ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Dna Sequences ◽  
Constitutive Heterochromatin ◽  
Karyotype Evolution ◽  
Telomeric Dna ◽  
A Genome ◽  
Functional Dna ◽  
Chromosome Regions

A (TTAGG)n-specific telomeric DNA probe was hybridized to 11 orthopteroid insect genomes by fluorescence in situ hybridization. Nine different genera, mainly distributed within two evolutionary branches with male chromosome numbers 2n = 23 and 2n = 17 were included in the analysis. Telomere sequences yielded positive signals in every telomere and there was a considerable number of interstitial telomeric-like sequences, mainly located at the distal end of some, but not all, subterminal chromosome regions. One of the species, Pyrgomorpha conica, showed massive hybridization signals associated with constitutive heterochromatin. The results are discussed along two lines: (i) the chromosomal evolutionary trends within this group of insects and (ii) the putative role that ITs may play in a genome when they are considered telomere-derived, but not telomere-functional, DNA sequences.Key words: telomere, insect chromosomes, karyotype evolution, fluorescence in situ hybridization.

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