A “hot spot” of recombination coincides with an interstitial telomeric sequence in the Armenian hamster

1993 ◽  
Vol 62 (2-3) ◽  
pp. 169-171 ◽  
Author(s):  
T. Ashley ◽  
DC. Ward
Keyword(s):  
Hot Spot ◽  
Telomeric Sequence ◽  
Interstitial Telomeric Sequence

scholarly journals Evolutionary analysis of chromosome end extension

2018 ◽  
Author(s):  
Haojing Shao ◽  
Chenxi Zhou ◽  
Minh Duc Cao ◽  
Lachlan J.M Coin
Keyword(s):  
Evolutionary Process ◽  
Chromosome Analysis ◽  
Telomeric Sequence ◽  
Extension Rate ◽  
Evolutionary Analysis ◽  
Interstitial Telomeric Sequence ◽  
Snp Data ◽  
Telomere Sequence ◽  
The Relationship ◽  
Subtelomeric Regions

There are substantial subtelomeric interstitial telomeric sequence (ITS) in the human genome, however the origin of these sequences is not well understood. We investigate the possibility that these ITS have arisen via a process of chromosome end extension to the telomere sequence. By analysing the relationship between subtelomeric duplication and ITS, we identify multiple ITS which were the ancestral chromosome telomeric capping sequence. Comparison of chromosome terminal sequence between 15 species reveals an ongoing evolutionary process of chromosome extension, with an average extension rate of 0.0020 bp per year per chromosome. Analysis of SNP data from 1000 genomes demonstrates reduced SNP diversity in subtelomeric regions, indicating that many terminal regions are younger than the remaining autosomal sequence.

Localization of the (TTAGGG)n telomeric sequence in zebrafish chromosomes

Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 136-138 ◽  
Author(s):  
E Gornung ◽  
I Gabrielli ◽  
L Sola
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Danio Rerio ◽  
Hot Spot ◽  
Telomeric Sequence ◽  
Recombination Site ◽  
Metaphase Chromosomes ◽  
Sequence Distribution

The distribution of the (TTAGGG)n telomeric sequence in Danio rerio (zebrafish) metaphase chromosomes was studied by fluorescence in situ hybridization. This study continues the analysis of the telomeric sequence distribution in fish and confirms that the (TTAGGG)n sequence is conserved in the telomeres of this group of vertebrates. The hybridization signals were restricted to telomeres in all the individuals analysed. With the degree of resolution currently available, no interstitial sites of the telomeric sequence were detected, which suggests that this type of hot-spot recombination site might be absent in zebrafish chromosomes.

scholarly journals Alternative Lengthening of Telomeres in the Budding Yeast Naumovozyma castellii

2019 ◽  
Vol 9 (10) ◽  
pp. 3345-3358 ◽  
Author(s):  
Marita Cohn ◽  
Ahu Karademir Andersson ◽  
Raquel Quintilla Mateo ◽  
Mirja Carlsson Möller
Keyword(s):  
Budding Yeast ◽  
Telomerase Activity ◽  
Telomeric Sequence ◽  
Wild Type ◽  
Alternative Lengthening Of Telomeres ◽  
Initiation Point ◽  
Interstitial Telomeric Sequence ◽  
Alternative Lengthening ◽  
Telomere Function ◽  
Linear Chromosomes

The enzyme telomerase ensures the integrity of linear chromosomes by maintaining telomere length. As a hallmark of cancer, cell immortalization and unlimited proliferation is gained by reactivation of telomerase. However, a significant fraction of cancer cells instead uses alternative telomere lengthening mechanisms to ensure telomere function, collectively known as Alternative Lengthening of Telomeres (ALT). Although the budding yeast Naumovozyma castellii (Saccharomyces castellii) has a proficient telomerase activity, we demonstrate here that telomeres in N. castellii are efficiently maintained by a novel ALT mechanism after telomerase knockout. Remarkably, telomerase-negative cells proliferate indefinitely without any major growth crisis and display wild-type colony morphology. Moreover, ALT cells maintain linear chromosomes and preserve a wild-type DNA organization at the chromosome termini, including a short stretch of terminal telomeric sequence. Notably, ALT telomeres are elongated by the addition of ∼275 bp repeats containing a short telomeric sequence and the subtelomeric DNA located just internally (TelKO element). Although telomeres may be elongated by several TelKO repeats, no dramatic genome-wide amplification occurs, thus indicating that the repeat addition may be regulated. Intriguingly, a short interstitial telomeric sequence (ITS) functions as the initiation point for the addition of the TelKO element. This implies that N. castellii telomeres are structurally predisposed to efficiently switch to the ALT mechanism as a response to telomerase dysfunction.

scholarly journals Evolutionary analysis of chromosome end extension

2018 ◽  
Author(s):  
Haojing Shao ◽  
Chenxi Zhou ◽  
Minh Duc Cao ◽  
Lachlan J.M Coin
Keyword(s):  
Evolutionary Process ◽  
Chromosome Analysis ◽  
Telomeric Sequence ◽  
Extension Rate ◽  
Evolutionary Analysis ◽  
Interstitial Telomeric Sequence ◽  
Snp Data ◽  
Telomere Sequence ◽  
The Relationship ◽  
Subtelomeric Regions

There are substantial subtelomeric interstitial telomeric sequence (ITS) in the human genome, however the origin of these sequences is not well understood. We investigate the possibility that these ITS have arisen via a process of chromosome end extension to the telomere sequence. By analysing the relationship between subtelomeric duplication and ITS, we identify multiple ITS which were the ancestral chromosome telomeric capping sequence. Comparison of chromosome terminal sequence between 15 species reveals an ongoing evolutionary process of chromosome extension, with an average extension rate of 0.0020 bp per year per chromosome. Analysis of SNP data from 1000 genomes demonstrates reduced SNP diversity in subtelomeric regions, indicating that many terminal regions are younger than the remaining autosomal sequence.

Co-located hAT transposable element and 5S rDNA in an interstitial telomeric sequence suggest the formation of Robertsonian fusion in armored catfish

Gene ◽  
2018 ◽  
Vol 650 ◽  
pp. 49-54 ◽  
Author(s):  
Larissa Glugoski ◽  
Lucia Giuliano-Caetano ◽  
Orlando Moreira-Filho ◽  
Marcelo R. Vicari ◽  
Viviane Nogaroto
Keyword(s):  
Transposable Element ◽  
5S Rdna ◽  
Telomeric Sequence ◽  
Robertsonian Fusion ◽  
Interstitial Telomeric Sequence

scholarly journals Karyotypic variation of Glanidium ribeiroi Haseman, 1911 (Siluriformes, Auchenipteridae) along the Iguazu river basin

2015 ◽  
Vol 75 (4 suppl 1) ◽  
pp. 215-221 ◽  
Author(s):  
R. L. Lui ◽  
D. R. Blanco ◽  
J. B. Traldi ◽  
V. P. Margarido ◽  
O. Moreira-Filho
Keyword(s):  
18S Rdna ◽  
5S Rdna ◽  
Terminal Region ◽  
Telomeric Sequence ◽  
Interstitial Telomeric Sequence ◽  
Rugged Topography ◽  
Karyotypic Variation ◽  
Preferential Location ◽  
Almost All ◽  
Submetacentric Pair

Abstract The Iguazu river is a tributary of the left margin of the Paraná river, isolated from this basin about 22 million years ago with the appearance of the Iguazu Falls. The Iguazu river is characterized by high endemism due to two factors: its rugged topography and the old isolation caused by formation of the Iguazu Falls. This study analyzed cytogenetically a population of Glanidium ribeiroi collected in a region at the final stretch of this basin, by Giemsa staining, C-banding, impregnation by silver nitrate, and FISH with probes of 5S rDNA, 18S rDNA, telomeric sequence [TTAGGG]n, and [GATA]n repeats. The diploid number was equal to 58 chromosomes. The heterochromatin was present in the terminal region of almost all chromosomes. The Ag-NORs were simple and presented interstitially on the short arm of the submetacentric pair 14, which was confirmed by FISH with 18S rDNA probe. The 5S rDNA-FISH marked only the submetacentric pair 16 on the long arm in interstitial position. The FISH with [TTAGGG]n probe presented all telomeres labeled as expected, with an absence of Interstitial Telomeric Sequence (ITS). The repetitive [GATA]n sequence was dispersed throughout the genome, with preferential location in the terminal region of all chromosomes. The data obtained are discussed herein with other species of Auchenipteridae, and other previously analyzed populations of G. ribeiroi from the Iguazu river, verifying differences among these populations, which should be mainly related to the rugged topography of this basin.

Mutation Spectrum in Patients with Wiskott-Aldrich Syndrome and X-linked Thrombocytopenia: Identification of Twelve Different Mutations in the WASP Gene

1996 ◽  
Vol 75 (04) ◽  
pp. 546-550 ◽  
Author(s):  
Marianne Schwartz ◽  
Albert Békássy ◽  
Mikael Donnér ◽  
Thomas Hertel ◽  
Stefan Hreidarson ◽  
...  
Keyword(s):  
Base Pair ◽  
Hot Spot ◽  
Missense Mutations ◽  
Nucleotide Substitutions ◽  
Exon 2 ◽  
Wiskott Aldrich Syndrome ◽  
Base Pair Deletion ◽  
Reliable Diagnosis ◽  
Wasp Gene ◽  
Detection Of Mutations

SummaryTwelve different mutations in the WASP gene were found in twelve unrelated families with Wiskott-Aldrich syndrome (WAS) or X-linked thrombocytopenia (XLT). Four frameshift, one splice, one nonsense mutation, and one 18-base-pair deletion were detected in seven patients with WAS. Only missense mutations were found in five patients diagnosed as having XLT. One of the nucleotide substitutions in exon 2 (codon 86) results in an Arg to Cys replacement. Two other nucleotide substitutions in this codon, R86L and R86H, have been reported previously, both giving rise to typical WAS symptoms, indicating a mutational hot spot in this codon. The finding of mutations in the WASP gene in both WAS and XLT gives further evidence of these syndromes being allelic. The relatively small size of the WASP gene facilitates the detection of mutations and a reliable diagnosis of both carriers and affected fetuses in families with WAS or XLT.

Challenges to immigrant associations and NGOs in contemporary Greece

2013 ◽  
Vol 10 (3) ◽  
pp. 342-358 ◽  
Author(s):  
Apostolos G. Papadopoulos ◽  
Christos Chalkias ◽  
Loukia-Maria Fratsea
Keyword(s):  
Civil Society ◽  
Economic Crisis ◽  
Hot Spot ◽  
Geographical Range ◽  
Legal Form ◽  
Social Actors ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Migrant Integration ◽  
Concentration Patterns

The paper explores the challenges faced today, in a context of severe economic crisis, by immigrant associations (ΙΜΑs) and Non-Governmental Organizations (NGOs) in Greece. The data analysed here was collected between October 2009 and February 2010 and incorporates references to all recorded migration-related social actors operating in Greece. The paper takes into account such indicators as legal form, objectives, financial capacity and geographical range of activity, concluding with a typology of civil society actors dealing with migration issues. This study aims at informing the migration policymaking and migrant integration processes. By a spatial hot-spot clustering of IMAs and NGOs, we also illustrate the concentration patterns of civil society actors in Greece.

Sign in / Sign up

Export Citation Format

Share Document