Satellite Chromosomes

2013 ◽  
pp. 332
Author(s):  
M.A. Ferguson-Smith
Keyword(s):  
Satellite Chromosomes

The nucleolar cycle in man

1977 ◽  
Vol 25 (1) ◽  
pp. 103-110
Author(s):  
M. Anastassova-Kristeva
Keyword(s):  
Gene Expression ◽  
Mitotic Division ◽  
Tissue Cultures ◽  
Nucleolar Number ◽  
Satellite Chromosomes ◽  
Nucleolar Cycle ◽  
Group D ◽  
Secondary Constrictions ◽  
Nucleolus Organizers

Tissue cultures of human embryonal kidney and ovary were examined. In the nuclei of both tissues, one to ten nucleoli have been found. The maximum number of nucleoli is connected with the gene expression of rDNA of the 10 nucleolus organizers of chromosome pairs Nos. 13, 14, 15, 21 and 22, which have secondary constrictions and are the satellite chromosomes in man. The small percentage of cells with 10, 9 and 8 nucleoli is attributed to the rapid association of 3 of the homologous acrocentrics (perhaps of group D). Two of the satellite (SAT) pairs probably associate later after mitosis. The process of fusion is dynamic, resulting in one interphase nucleous—a manifestation of the association of all SAT chromosomes. Dissociation of the nucleolus occurs upon entering prophase, due to the condensation of the chromosomes and retreat of rDNA to the respective secondary constrictions. As a result, the nucleolar number increases again. The pattern of the nucleolar kinetics within the course of one mitotic division is described.

Chromosome evolution in wild oat grasses (Aveneae) revealed by molecular phylogeny

Genome ◽  
2009 ◽  
Vol 52 (4) ◽  
pp. 361-380 ◽  
Author(s):  
Grit Winterfeld ◽  
Elke Döring ◽  
Martin Röser
Keyword(s):  
Molecular Phylogeny ◽  
Dna Sequences ◽  
Chromosome Evolution ◽  
5S Rdna ◽  
Fluorochrome Staining ◽  
Satellite Dnas ◽  
A Genome ◽  
Satellite Chromosomes ◽  
Species Specific

Karyotype structures revealed by in situ hybridization with ribosomal and satellite DNAs and fluorochrome staining of AT- or GC-rich regions are reported for 23 diploid to tetraploid taxa of Aveneae genera Arrhenatherum , Avena , Helictotrichon , and Pseudarrhenatherum . Chromosomal features are compared with a molecular phylogeny generated on nuclear ribosomal (ITS, 5S) and chloroplast (matK) DNA sequences. Ancestral chromosomal character states are (1) two satellite chromosomes per set of x = 7, (2) 5S rDNA localized in nonsatellite chromosomes, (3) large chromosomes with (4) rather equal lengths of their respective chromosome arms, (5) sets with strong variance of chromosome lengths, (6) absence or small amounts of heterochromatin, and (7) absence or no detectable amplification of the satellite DNAs tested. Overall, most karyotype characteristics are species specific, but common patterns were found for the species of two large subgenera of Helictotrichon. Pseudarrhenatherum, although nested in the molecular phylogeny within Helictotrichon subgenus Helictotrichon, deviates strongly in karyotype characters such as Arrhenatherum as sister of Avena. The karyotype of Helictotrichon jahandiezii , sister to the clade of Helictotrichon subgenera Helictotrichon, Avena, and Arrhenatherum, strongly resembles that of Avena macrostachya . Karyotype features suggest that perennial A. macrostachya and H. jahandiezii are close to the C-genome species of annual Avena, whereas the Avena A genome resembles that of Arrhenatherum.

Nucleolus formation in structurally reconstructed barley karyotypes with six satellite chromosomes

Chromosoma ◽  
1977 ◽  
Vol 62 (2) ◽  
pp. 111-117 ◽  
Author(s):  
M. Anastassova-Kristeva ◽  
H. Nicoloff ◽  
G. K�nzel ◽  
R. Rieger
Keyword(s):  
Satellite Chromosomes

Heterochromatin diversity and chromosome morphology in wheats analyzed by the HKG banding technique

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 956-965 ◽  
Author(s):  
X. M. Shang ◽  
R. C. Jackson ◽  
H. T. Nguyen
Keyword(s):  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Chromosome Morphology ◽  
Banding Technique ◽  
Hypotonic Solution ◽  
Drying Time ◽  
Banding Patterns ◽  
Satellite Chromosomes ◽  
Water Treatments

Chromosome banding patterns in diploid, tetraploid, and hexaploid wheats were clearly revealed and compared by the HCl–KOH–Giemsa banding technique. Heterochromatin diversity of chromosomes 4A, 4B, 5B, and satellite chromosomes IB and 6B was shown at the centromeric, pericentric, telomeric, interstitial, and satellite regions. Quantitative comparisons were made of the amount of heterochromatin in chromosomes 4A, 4B, and 5B and among genomes of 'Chinese Spring' (Triticum aestivum). Genome relationships were evaluated in the extant diploid and polyploid wheat taxa. Modifications of the banding technique by hypotonic solution and water treatments and by changing air-drying time of slides influenced centromeric, interstitial, and nucleolar organizer region banding patterns, greatly increased the volume of chromosomes, produced different banding patterns, and significantly changed the nuclear morphologies.Key words: HKG-banding, diversity, chromosomes, genome relationships, Triticum.

scholarly journals Reconstruction of evolutionary trajectories of coffee chromosomes

2019 ◽  
Author(s):  
Jing Li ◽  
Jiaqing Yuan ◽  
Yuhao Zhao ◽  
Fanbo Meng ◽  
Chao Liu ◽  
...  
Keyword(s):  
Evolutionary Process ◽  
End Joining ◽  
Chromosome Fusion ◽  
Plant Chromosomes ◽  
Evolutionary Trajectories ◽  
Widespread Phenomenon ◽  
Satellite Chromosomes ◽  
Chromosome Fission ◽  
Chromosome Fusions ◽  
Fusion Mode

Abstract Background Polyploidization is a widespread phenomenon in plants, especially in angiosperms. Because of the rearrangement of chromosomes and the loss of genes, the number of plant chromosomes will reduce. Studies have shown that core dicotyledons are derived from ancestors with seven proto-chromosomes, which triplicated in a core-eudicot-common hexaploidization. Therefore, dicotyledon with different chromosome numbers have evolved on the basis of 21 chromosomes. On this basis, we selected grape as the intermediate reference species to infer the karyotype evolutionary process of coffee. Results We found that all the chromosome fusion forms in grape were end-end joining, and 7 (70.0%) chromosome fusion forms in coffee were end-end joining. In the process of grape forming 19 chromosomes, there were three chromosome fusions and one chromosome fission. In the process of coffee 11 chromosomes formation, 10 chromosome fusions occurred. During the process, we inferred that satellite chromosomes formed by telomeres from the same or different chromosomes were produced; and the lost of them resulted in chromosome number reduction Conclusions Notably, we found that the major fusion mode of chromosomes in coffee is end-end joining, which is well explained by telomere-centric model, shared by grape and possibly by many other eudicots. This is contrastively different from the observation of monocot plants like grasses, in which nested chromosome fusions often occurred. The present work will help to understand the structural and functional innovations of plant chromosomes.

Karyological studies on eight species of Onobrychis genus in Turkey

Biologia ◽  
2011 ◽  
Vol 66 (6) ◽  
Author(s):  
Hakan Sepet ◽  
İrfan Emre ◽  
Yaşar Kiran ◽  
Murat Kursat ◽  
Ahmet Sahin
Keyword(s):  
Chromosome Numbers ◽  
The Other ◽  
Karyotype Asymmetry ◽  
Satellite Chromosomes

AbstractThis study used karyological techniques to determine the chromosome numbers and morphology of eight species of Onobrychis L. (O. caput-galli (L.) Lam, O. aequidentata (Sibth. & Sm.) d’ Urv, O. fallax Freyn & Sint. var. fallax, O. lasiostachya Boiss, O. viciifolia Scop., O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu, O. hypargyrea Boiss. and O. cappadocica Boiss.). The results of this study determined the chromosome numbers of O. cappadocica as 2n = 16; O. viciifolia as 2n = 28 and the other species as 2n = 14 The karyotypes of species consisted of median-centromeric (m) or submedian-centromeric (sm) chromosomes. However, O. oxyodonta Boiss. subsp. armena (Bois. & Huet) Aktoklu was found to have only the median-centromeric (m) chromosomes. According to the results of the present study, of the eight Onobrychis taxa, only O. hypargyrea has a pair of satellite chromosomes (sat-chromosome). Furthermore, this study detected karyotype asymmetry.

CHROMOSOME BREAKAGE INDUCED IN VICIA FABA ROOT TIPS BY 2,4,6-TRI(ETHYLENEIMINO)-1,3,5-TRIAZINE

1959 ◽  
Vol 37 (3) ◽  
pp. 403-411 ◽  
Author(s):  
Resa Wakonig ◽  
T. J. Arnason
Keyword(s):  
Vicia Faba ◽  
Heterochromatic Region ◽  
Chromosome Breakage ◽  
Equal Frequency ◽  
Root Tips ◽  
Satellite Chromosome ◽  
Root Cells ◽  
Chromosome Breaks ◽  
Satellite Chromosomes ◽  
Unit Of Length

After a 12-hour treatment in 10−5 M solution of 2,4,6-tri(ethyleneimino)-1,3,5-triazine (TEM), up to 29% of Vicia and 31% of Allium root cells in anaphase had bridges or fragments. The most abundant metaphase aberrations were chromosome breaks and chromatid interchanges. Aberrations were more numerous after 6-hour treatment with 2 × 10−5 M than after 12-hour treatment with 10−5 M solution. The peak aberration frequencies were reached at 36 hours after 2 × 10−5 M treatments and slightly earlier with weaker solutions. Many chromosomes had incomplete breaks. Sister reunions of chromatids occurred with equal frequency in centric and acentric fragments. Sister reunion was 1.5 times as frequent as chromatid exchange. Along the length of the satellite chromosome, breaks occurred at random except for a slight favoring of the heterochromatic region. Per unit of length the short chromosomes were about 3 times as susceptible to breakage and exchange as satellite chromosomes. TEM introduced through cut stems had no discernible effects on Tradescantia microspore chromosomes even after 3 to 5 days of treatment.

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