scholarly journals Chromosomal variability in Brazilian species of Anthurium Schott (Araceae): Heterochromatin, polyploidy, and B chromosomes

2019 ◽  
Vol 42 (3) ◽  
pp. 635-642
Author(s):  
Sarah do Nascimento ◽  
Marcus Alberto Nadruz Coelho ◽  
Joel M. P. Cordeiro ◽  
Leonardo P. Felix
Keyword(s):  
B Chromosomes ◽  
Brazilian Species ◽  
Chromosomal Variability

scholarly journals Chromosomal Instability at Fragile Sites in Blue Foxes, Silver Foxes, and Their Interspecific Hybrids

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1743
Author(s):  
Marta Kuchta-Gładysz ◽  
Ewa Wójcik ◽  
Anna Grzesiakowska ◽  
Katarzyna Rymuza ◽  
Olga Szeleszczuk
Keyword(s):  
Interspecific Hybrids ◽  
Genome Stability ◽  
Diploid Number ◽  
Fragile Sites ◽  
B Chromosomes ◽  
Silver Fox ◽  
Chromosomal Breaks ◽  
Blue Fox ◽  
Chromosomal Fragile Sites ◽  
Karyotypic Variation

A cytogenetic assay based on fragile sites (FS) enables the identification of breaks, chromatid gaps, and deletions. In healthy individuals, the number of these instabilities remains low. Genome stability in these species is affected by Robertsonian translocations in the karyotype of the blue fox and by B chromosomes in the silver fox. The aims of the study were to characterise the karyotype of blue foxes, silver foxes, and their hybrids and to identify chromosomal fragile sites used to evaluate genome stability. The diploid number of A chromosomes in blue foxes ranged from 48 to 50, while the number of B chromosomes in silver foxes varied from one to four, with a constant number of A chromosomes (2n = 34). In interspecific hybrids, both types of karyotypic variation were identified, with the diploid number of A chromosomes ranging from 40 to 44 and the number of B chromosomes varying from 0 to 3. The mean frequency of FS in foxes was 4.06 ± 0.19: 4.61 ± 0.37 in blue foxes, 3.46 ± 0.28 in silver foxes, and 4.12 ± 0.22 in hybrids. A relationship was identified between an increased number of A chromosomes in the karyotype of the hybrids and the frequency of chromosomal breaks. The FS assay was used as a biomarker for the evaluation of genomic stability in the animals in the study.

scholarly journals New Data on Organization and Spatial Localization of B-Chromosomes in Cell Nuclei of the Yellow-Necked Mouse Apodemus flavicollis

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1819
Author(s):  
Tatyana Karamysheva ◽  
Svetlana Romanenko ◽  
Alexey Makunin ◽  
Marija Rajičić ◽  
Alexey Bogdanov ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Sex Chromosomes ◽  
Interphase Nucleus ◽  
Spatial Organization ◽  
Three Dimensional ◽  
Dna Probes ◽  
B Chromosomes ◽  
Apodemus Flavicollis ◽  
Yellow Necked Mouse

The gene composition, function and evolution of B-chromosomes (Bs) have been actively discussed in recent years. However, the additional genomic elements are still enigmatic. One of Bs mysteries is their spatial organization in the interphase nucleus. It is known that heterochromatic compartments are not randomly localized in a nucleus. The purpose of this work was to study the organization and three-dimensional spatial arrangement of Bs in the interphase nucleus. Using microdissection of Bs and autosome centromeric heterochromatic regions of the yellow-necked mouse (Apodemus flavicollis) we obtained DNA probes for further two-dimensional (2D)- and three-dimensional (3D)- fluorescence in situ hybridization (FISH) studies. Simultaneous in situ hybridization of obtained here B-specific DNA probes and autosomal C-positive pericentromeric region-specific probes further corroborated the previously stated hypothesis about the pseudoautosomal origin of the additional chromosomes of this species. Analysis of the spatial organization of the Bs demonstrated the peripheral location of B-specific chromatin within the interphase nucleus and feasible contact with the nuclear envelope (similarly to pericentromeric regions of autosomes and sex chromosomes). It is assumed that such interaction is essential for the regulation of nuclear architecture. It also points out that Bs may follow the same mechanism as sex chromosomes to avoid a meiotic checkpoint.

scholarly journals Repetitive DNA landscape in essential A and supernumerary B chromosomes of Festuca pratensis Huds

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rahman Ebrahimzadegan ◽  
Andreas Houben ◽  
Ghader Mirzaghaderi
Keyword(s):  
Repetitive Sequences ◽  
Nuclear Genome ◽  
B Chromosome ◽  
B Chromosomes ◽  
Festuca Pratensis ◽  
Ltr Retrotransposons ◽  
Chromosome Identification ◽  
Satellite Repeats ◽  
Low Pass ◽  
Illumina Sequence

AbstractHere, we characterized the basic properties of repetitive sequences in essential A and supernumerary B chromosomes of Festuca pratensis Huds. This was performed by comparative analysis of low-pass Illumina sequence reads of B chromosome lacking (−B) and B chromosome containing (+B) individuals of F. pratensis. 61% of the nuclear genome is composed of repetitive sequences. 43.1% of the genome are transposons of which DNA transposons and retrotransposons made up 2.3% and 40.8%, respectively. LTR retrotransposons are the most abundant mobile elements and contribute to 40.7% of the genome and divided into Ty3-gypsy and Ty1-copia super families with 32.97% and 7.78% of the genome, respectively. Eighteen different satellite repeats were identified making up 3.9% of the genome. Five satellite repeats were used as cytological markers for chromosome identification and genome analysis in the genus Festuca. Four satellite repeats were identified on B chromosomes among which Fp-Sat48 and Fp-Sat253 were specific to the B chromosome of F. pratensis.

Occurrence and Origin of Supernumerary Chromosomes in Partamona (Hymenoptera: Apidae: Meliponini)

2016 ◽  
Vol 150 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Diana P. Machado ◽  
Elder A. Miranda ◽  
Mariana C. Dessi ◽  
Camila P. Sabadini ◽  
Marco A. Del Lama
Keyword(s):  
High Frequency ◽  
Scar Marker ◽  
Sequence Data ◽  
Low Frequency ◽  
B Chromosomes ◽  
First Report ◽  
Supernumerary Chromosomes

Samples from 861 colonies of 12 Partamona species from 125 Brazilian localities were analysed for a SCAR marker specific to the B chromosomes of P. helleri. We identified the SCAR marker in 6 of the 12 species analysed, including 2 (P. gregaria and P. chapadicola) from the pearsoni clade. This is the first report on the presence of this marker in Partamona species that are not included in the cupira clade, which indicates that the B chromosomes probably are more widespread in this genus than previously thought. The analysis revealed a high frequency of the SCAR marker in the samples of P. helleri (0.47), P. cupira (0.46), and P. rustica (0.29), and a low frequency in P. aff. helleri (0.06). The frequency of the marker in P. helleri was correlated with the latitude of the sampling locality, decreasing from north to south. Sequence data on the SCAR marker from 50 individuals of the 6 species in which the presence of this marker was shown revealed a new scenario for the origin of the B chromosomes in Partamona.

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