scholarly journals Interstitial Arabidopsis-Type Telomeric Repeats in Asteraceae

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2794
Author(s):  
Alexis J. Maravilla ◽  
Marcela Rosato ◽  
Inés Álvarez ◽  
Gonzalo Nieto Feliner ◽  
Josep A. Rosselló
Keyword(s):  
Structural Changes ◽  
Tandem Repeats ◽  
Phylogenetic Signal ◽  
Telomeric Sequence ◽  
Mitotic Chromosomes ◽  
Telomeric Repeats ◽  
Early Diversification ◽  
Karyological Evolution ◽  
Interstitial Telomeric Repeats

Tandem repeats of telomeric-like motifs at intra-chromosomal regions, known as interstitial telomeric repeats (ITR), have drawn attention as potential markers of structural changes, which might convey information about evolutionary relationships if preserved through time. Building on our previous work that reported outstanding ITR polymorphisms in the genus Anacyclus, we undertook a survey across 132 Asteraceae species, focusing on the six most speciose subfamilies and considering all the ITR data published to date. The goal was to assess whether the presence, site number, and chromosomal location of ITRs convey any phylogenetic signal. We conducted fluorescent in situ hybridization (FISH) using an Arabidopsis-type telomeric sequence as a probe on karyotypes obtained from mitotic chromosomes. FISH signals of ITR sites were detected in species of subfamilies Asteroideae, Carduoideae, Cichorioideae, Gymnarhenoideae, and Mutisioideae, but not in Barnadesioideae. Although six small subfamilies have not yet been sampled, altogether, our results suggest that the dynamics of ITR formation in Asteraceae cannot accurately trace the complex karyological evolution that occurred since the early diversification of this family. Thus, ITRs do not convey a reliable signal at deep or shallow phylogenetic levels and cannot help to delimitate taxonomic categories, a conclusion that might also hold for other important families such as Fabaceae.

scholarly journals Insight into the Chromosome Structure of the Cultivated Tetraploid Alfalfa (Medicago sativa subsp. sativa L.) by a Combined Use of GISH and FISH Techniques

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 542
Author(s):  
Egizia Falistocco
Keyword(s):  
In Situ Hybridization ◽  
Medicago Sativa ◽  
Tandem Repeats ◽  
Chromosome Structure ◽  
Substantial Part ◽  
Telomeric Repeats ◽  
Evolutionary Pathway ◽  
Suitable Material ◽  
Interstitial Telomeric Repeats

Cytogenetic research in Medicago sativa subsp. sativa L., the cultivated tetraploid alfalfa (2n = 4x = 32), has lagged behind other crops mostly due to the small size and the uniform morphology of its chromosomes. However, in the last decades, the development of molecular cytogenetic techniques based on in situ hybridization has largely contributed to overcoming these limitations. The purpose of this study was to extend our knowledge about the chromosome structure of alfalfa by using a combination of genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) techniques. The results of self-GISH (sGISH) suggested that a substantial part of the repetitive fraction of the genome of subsp. sativa is constituted by tandem repeats typical of satellite DNA. The coincidence of sGISH and C-banding patterns supported this assumption. The FISH mapping of the Arabidopsis-type TTTAGGG telomeric repeats demonstrated, for the first time, that the alfalfa telomeres consist of this type of sequence and revealed a massive presence of interstitial telomeric repeats (ITRs). In the light of this finding M. sativa appears to be a suitable material for studying the origin and function of such extra telomeric repeats. To further exploit this result, investigation will be extended to the diploid subspp. coerulea and falcata in order to explore possible connections between the distribution of ITRs, the ploidy level, and the evolutionary pathway of the taxa.

scholarly journals Shortened Telomeres Involved in a Case With a Jumping Translocation at 1q21

Blood ◽  
1998 ◽  
Vol 91 (5) ◽  
pp. 1514-1519 ◽  
Author(s):  
Shinji Hatakeyama ◽  
Kazuhiro Fujita ◽  
Hiraku Mori ◽  
Mitsuhiro Omine ◽  
Fuyuki Ishikawa
Keyword(s):  
Molecular Study ◽  
Hybridization Experiment ◽  
Proximal Region ◽  
Telomeric Repeat ◽  
Telomeric Sequence ◽  
Nucleotide Sequencing ◽  
Telomeric Repeats ◽  
Base Mismatch ◽  
Acute Myelomonocytic Leukemia

Abstract The jumping translocation (JT) is a rare chromosomal abnormality in which a specific chromosomal segment translocates onto the ends of various chromosomes (jumps). In most cases, the region distal to 1q21 jumps onto numerous different telomeres. Here we report a molecular study of the JT involving 1q21 found in a patient with acute myelomonocytic leukemia that had transformed from myelodysplastic syndrome (MDS). This is the first report describing the analysis of the molecular structure of the JT. We demonstrated the presence of a stretch of telomeric repeats at the breakpoint by means of a fluorescence in situ hybridization experiment, molecular cloning, and nucleotide sequencing of the fused region. A significant amount of variant telomeric repeats (a telomeric sequence having one-base mismatch within the authentic telomeric repeat TTAGGG) was found in this region. The variant telomeric repeat has been shown to be present in the proximal region of telomeres and does not perform telomeric functions by itself. Therefore, these results indicated that the telomeres had already been critically shortened when the jumps occurred. We suggest that the extended proliferation of cancer cells during the premalignant stage, such as MDS, results in chromosomal instability due to the loss of telomeric functions.

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 Shortened Telomeres Involved in a Case With a Jumping Translocation at 1q21

Blood ◽  
1998 ◽  
Vol 91 (5) ◽  
pp. 1514-1519 ◽  
Author(s):  
Shinji Hatakeyama ◽  
Kazuhiro Fujita ◽  
Hiraku Mori ◽  
Mitsuhiro Omine ◽  
Fuyuki Ishikawa
Keyword(s):  
Molecular Study ◽  
Hybridization Experiment ◽  
Proximal Region ◽  
Telomeric Repeat ◽  
Telomeric Sequence ◽  
Nucleotide Sequencing ◽  
Telomeric Repeats ◽  
Base Mismatch ◽  
Acute Myelomonocytic Leukemia

The jumping translocation (JT) is a rare chromosomal abnormality in which a specific chromosomal segment translocates onto the ends of various chromosomes (jumps). In most cases, the region distal to 1q21 jumps onto numerous different telomeres. Here we report a molecular study of the JT involving 1q21 found in a patient with acute myelomonocytic leukemia that had transformed from myelodysplastic syndrome (MDS). This is the first report describing the analysis of the molecular structure of the JT. We demonstrated the presence of a stretch of telomeric repeats at the breakpoint by means of a fluorescence in situ hybridization experiment, molecular cloning, and nucleotide sequencing of the fused region. A significant amount of variant telomeric repeats (a telomeric sequence having one-base mismatch within the authentic telomeric repeat TTAGGG) was found in this region. The variant telomeric repeat has been shown to be present in the proximal region of telomeres and does not perform telomeric functions by itself. Therefore, these results indicated that the telomeres had already been critically shortened when the jumps occurred. We suggest that the extended proliferation of cancer cells during the premalignant stage, such as MDS, results in chromosomal instability due to the loss of telomeric functions.

Distribution of telomeric repeats and their role in the healing of broken chromosome ends in wheat

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 844-848 ◽  
Author(s):  
Joanna E. Werner ◽  
Rama S. Kota ◽  
Bikram S. Gill ◽  
T. R. Endo
Keyword(s):  
In Situ Hybridization ◽  
De Novo ◽  
Wheat Chromosome ◽  
Variable Number ◽  
Mitotic Chromosomes ◽  
Telomeric Repeats ◽  
Telomeric Sequences ◽  
Chromosome Healing ◽  
Synthetic Probe

The distribution of the telomeric repeats in common wheat and their role in the healing of broken ends of deleted chromosomes was studied. In situ hybridization to mitotic chromosomes was carried out using a synthetic probe that was derived from the sequence of the telomeric repeats of Arabidopsis thaliana. Sites of hybridization were visualized as double dots at both ends of each wheat chromosome. Variation in the strength of the signal that was detected among chromosome arms might be due to the variable number of telomeric repeats of each chromosome end. While signals were absent on normal chromosomes at the pericentric and intercalary regions, hybridization sites were detected at the broken chromosome ends of all deleted chromosomes included in the study. All telocentric chromosomes of multitelocentric lines of 'Chinese Spring' showed a strong signal at the centromeric region. The results suggest that a de novo chromosome healing mechanism exists in wheat involving the addition of the telomeric sequences to the ends of broken chromosome. Further evidence indicated that the healing of broken ends is probably intrinsic to replication during gametogenesis.Key words: in situ hybridization, telomeric sequences, deleted chromosomes, chromosome healing, telosome.

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.

Molecular cytogenetic analysis of supernumerary heterochromatic segments in Rumex acetosa

Genome ◽  
2000 ◽  
Vol 43 (2) ◽  
pp. 391-397 ◽  
Author(s):  
Fukashi Shibata ◽  
Masahiro Hizume ◽  
Yuzo Kuroki
Keyword(s):  
In Situ Hybridization ◽  
Copy Number ◽  
Tandem Repeats ◽  
Mitotic Chromosomes ◽  
Dioecious Plant ◽  
Rumex Acetosa ◽  
Interphase Nuclei ◽  
Heterochromatic Segment ◽  
Molecular Cytogenetic

The dioecious plant Rumex acetosa shows intraspecific karyotype variation, caused by supernumerary heterochromatic segments or DAPI (4',6-diamidino-2 phenylindole)-bands at the ends of the short arms of three pairs of autosomes. A DNA sequence (RAE730) specific to the supernumerary heterochromatic segments was cloned and sequenced. RAE730 was about 730 bp and AT-rich (71% AT-content). Using fluorescence in situ hybridization (FISH), RAE730 was localized in the supernumerary DAPI-positive heterochromatic segments on several mitotic chromosomes and chromocenters in interphase nuclei, but not in the DAPI-bands of Y or B chromosomes. RAE730 was tandemly arranged in the genome, and the copy number varied between plants from 40 000 to 304 000 copies per 2C, corresponding to the relative amount of supernumerary heterochromatic segments per genome. These results indicate that the karyotype variation caused by the supernumerary heterochromatic segment was generated by amplification or reduction of the tandem repeats of RAE730. Key words: Rumex acetosa, repetitive sequence, supernumerary heterochromatic segment, intraspecific karyotype variation, DAPI-band.

scholarly journals Physical mapping of repetitive oligonucleotides facilitates the establishment of a genome map-based karyotype to identify chromosomal variations in peanut

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Liuyang Fu ◽  
Qian Wang ◽  
Lina Li ◽  
Tao Lang ◽  
Junjia Guo ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Physical Mapping ◽  
Tandem Repeats ◽  
Genetic Research ◽  
Diploid Species ◽  
Reference Sequence ◽  
A Genome ◽  
Genome Map ◽  
Chromosomal Variants

Abstract Background Chromosomal variants play important roles in crop breeding and genetic research. The development of single-stranded oligonucleotide (oligo) probes simplifies the process of fluorescence in situ hybridization (FISH) and facilitates chromosomal identification in many species. Genome sequencing provides rich resources for the development of oligo probes. However, little progress has been made in peanut due to the lack of efficient chromosomal markers. Until now, the identification of chromosomal variants in peanut has remained a challenge. Results A total of 114 new oligo probes were developed based on the genome-wide tandem repeats (TRs) identified from the reference sequences of the peanut variety Tifrunner (AABB, 2n = 4x = 40) and the diploid species Arachis ipaensis (BB, 2n = 2x = 20). These oligo probes were classified into 28 types based on their positions and overlapping signals in chromosomes. For each type, a representative oligo was selected and modified with green fluorescein 6-carboxyfluorescein (FAM) or red fluorescein 6-carboxytetramethylrhodamine (TAMRA). Two cocktails, Multiplex #3 and Multiplex #4, were developed by pooling the fluorophore conjugated probes. Multiplex #3 included FAM-modified oligo TIF-439, oligo TIF-185-1, oligo TIF-134-3 and oligo TIF-165. Multiplex #4 included TAMRA-modified oligo Ipa-1162, oligo Ipa-1137, oligo DP-1 and oligo DP-5. Each cocktail enabled the establishment of a genome map-based karyotype after sequential FISH/genomic in situ hybridization (GISH) and in silico mapping. Furthermore, we identified 14 chromosomal variants of the peanut induced by radiation exposure. A total of 28 representative probes were further chromosomally mapped onto the new karyotype. Among the probes, eight were mapped in the secondary constrictions, intercalary and terminal regions; four were B genome-specific; one was chromosome-specific; and the remaining 15 were extensively mapped in the pericentric regions of the chromosomes. Conclusions The development of new oligo probes provides an effective set of tools which can be used to distinguish the various chromosomes of the peanut. Physical mapping by FISH reveals the genomic organization of repetitive oligos in peanut chromosomes. A genome map-based karyotype was established and used for the identification of chromosome variations in peanut following comparisons with their reference sequence positions.

Sign in / Sign up

Export Citation Format

Share Document