Chromosome banding patterns and the nucleolar organizer region of the eastern mole (Scalopus aquaticus)

1976 ◽  
Vol 32 (10) ◽  
pp. 1276-1277 ◽  
Author(s):  
T. L. Yates ◽  
A. D. Stock ◽  
D. J. Schmidly
Keyword(s):  
Chromosome Banding ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Banding Patterns

Pattern of X-Y chromosome pairing in the Taiwan vole, Microtus kikuchii

Genome ◽  
2001 ◽  
Vol 44 (1) ◽  
pp. 27-31 ◽  
Author(s):  
K Mekada ◽  
M Harada ◽  
L K Lin ◽  
K Koyasu ◽  
P M Borodin ◽  
...  
Keyword(s):  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Sex Chromosomes ◽  
Meiotic Prophase ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
The Other ◽  
Banding Patterns ◽  
Y Chromosomes

Pairing of X and Y chromosomes at meiotic prophase and the G- and C-banding patterns and nucleolar organizer region (NOR) distribution were analyzed in Microtus kikuchii. M. kikuchii is closely related to M. oeconomus and M. montebelli, karyologically and systematically. The formation of a synaptonemal complex between the X and Y chromosomes at pachytene and end-to-end association at diakinesis – metaphase I are only observed in three species in the genus Microtus; M. kikuchii, M. oeconomus, and M. montebelli. All the other species that have been studied so far have had asynaptic X–Y chromosomes. These data confirm that M. kikuchii, M. oeconomus, and M. montebelli are very closely related, and support the separation of asynaptic and synaptic groups on the phylogenetic tree.Key words: Microtus kikuchii, Microtus phylogeny, karyotype, synaptic sex chromosomes, synaptonemal complex.

Fluorescent banding patterns of the chromosomes of the genus Salmo

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 193-197 ◽  
Author(s):  
Ruth B. Phillips ◽  
Sheila E. Hartley
Keyword(s):  
Great Britain ◽  
North America ◽  
Acrocentric Chromosome ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Salmo Gairdneri ◽  
Chromomycin A3 ◽  
Banding Patterns ◽  
Fluorescent Banding

The fluorescent banding patterns of the chromosomes of Salmo gairdneri (rainbow trout), Salmo trutta (brown trout), and Salmo salar (Atlantic salmon) from North America and Great Britain are described. Quinacrine stained a subset of C bands in S. gairdneri and S. salar from North America. No bright quinacrine (Q) bands were found on the chromosomes of S. salar from Great Britain or the chromosomes from any of the three stocks of S. trutta that were examined. Q bands were found at the centromeres of three to seven different chromosome pairs in S. gairdneri, including the pair that has been identified as the sex chromosome pair in some populations. In S. salar from North America the Q bands were found at the teleomeres of three to four chromosome pairs and at interstitial locations in the 10–13 large acrocentric chromosome pairs. Chromomycin A3 stained either the nucleolar organizer region or the adjacent heterochromatin or both in all three species. In S. trutta the entire short arm of the acrocentric chromosome containing the nucleolar organizer region always stained with chromomycin A3 while in S. gairdneri and S. salar the staining properties of the NOR and adjacent heterochromatin were polymorphic.Key words: banding, C-, Q-; Salmo; trout.

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 Comparative FISH analysis of Senna tora tandem repeats revealed insights into the chromosome dynamics in Senna

2021 ◽  
Vol 43 (3) ◽  
pp. 237-249 ◽  
Author(s):  
Thanh Dat Ta ◽  
Nomar Espinosa Waminal ◽  
Thi Hong Nguyen ◽  
Remnyl Joyce Pellerin ◽  
Hyun Hee Kim
Keyword(s):  
Tandem Repeats ◽  
Chromosomal Rearrangements ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Pericentromeric Region ◽  
Its2 Sequence ◽  
Fish Analysis ◽  
Chromosomal Distribution ◽  
Chromosome Dynamics

Abstract Background DNA tandem repeats (TRs) are often abundant and occupy discrete regions in eukaryotic genomes. These TRs often cause or generate chromosomal rearrangements, which, in turn, drive chromosome evolution and speciation. Tracing the chromosomal distribution of TRs could therefore provide insights into the chromosome dynamics and speciation among closely related taxa. The basic chromosome number in the genus Senna is 2n = 28, but dysploid species like Senna tora have also been observed. Objective To understand the dynamics of these TRs and their impact on S. tora dysploidization. Methods We performed a comparative fluorescence in situ hybridization (FISH) analysis among nine closely related Senna species and compared the chromosomal distribution of these repeats from a cytotaxonomic perspective by using the ITS1-5.8S-ITS2 sequence to infer phylogenetic relationships. Results Of the nine S. tora TRs, two did not show any FISH signal whereas seven TRs showed similar and contrasting patterns to other Senna species. StoTR01_86, which was localized in the pericentromeric regions in all S. tora, but not at the nucleolar organizer region (NOR) site, was colocalized at the NOR site in all species except in S. siamea. StoTR02_7_tel was mostly localized at chromosome termini, but some species had an interstitial telomeric repeat in a few chromosomes. StoTR05_180 was distributed in the subtelomeric region in most species and was highly amplified in the pericentromeric region in some species. StoTR06_159 was either absent or colocalized in the NOR site in some species, and StoIGS_463, which was localized at the NOR site in S. tora, was either absent or localized at the subtelomeric or pericentromeric regions in other species. Conclusions These data suggest that TRs play important roles in S. tora dysploidy and suggest the involvement of 45S rDNA intergenic spacers in “carrying” repeats during genome reshuffling.

scholarly journals The genomic structure of a human chromosome 22 nucleolar organizer region determined by TAR cloning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jung-Hyun Kim ◽  
Vladimir N. Noskov ◽  
Aleksey Y. Ogurtsov ◽  
Ramaiah Nagaraja ◽  
Nikolai Petrov ◽  
...  
Keyword(s):  
Genomic Structure ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Chromosome 21 ◽  
Reference Sequence ◽  
Chromosome 22 ◽  
Rdna Variation ◽  
High Level ◽  
Tar Cloning

AbstractThe rDNA clusters and flanking sequences on human chromosomes 13, 14, 15, 21 and 22 represent large gaps in the current genomic assembly. The organization and the degree of divergence of the human rDNA units within an individual nucleolar organizer region (NOR) are only partially known. To address this lacuna, we previously applied transformation-associated recombination (TAR) cloning to isolate individual rDNA units from chromosome 21. That approach revealed an unexpectedly high level of heterogeneity in human rDNA, raising the possibility of corresponding variations in ribosome dynamics. We have now applied the same strategy to analyze an entire rDNA array end-to-end from a copy of chromosome 22. Sequencing of TAR isolates provided the entire NOR sequence, including proximal and distal junctions that may be involved in nucleolar function. Comparison of the newly sequenced rDNAs to reference sequence for chromosomes 22 and 21 revealed variants that are shared in human rDNA in individuals from different ethnic groups, many of them at high frequency. Analysis infers comparable intra- and inter-individual divergence of rDNA units on the same and different chromosomes, supporting the concerted evolution of rDNA units. The results provide a route to investigate further the role of rDNA variation in nucleolar formation and in the empirical associations of nucleoli with pathology.

Nucleolar organizer region staining patterns in paraffin-embedded tissue cells from human skin cancers

2005 ◽  
Vol 32 (5) ◽  
pp. 323-328 ◽  
Author(s):  
Rosana F. Romao-Correa ◽  
Durvanei A. Maria ◽  
Mithitaka Soma ◽  
Mirian N. Sotto ◽  
Jose Antonio Sanches ◽  
...  
Keyword(s):  
Human Skin ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Skin Cancers ◽  
Tissue Cells

Nucleologenesis in Trypanosoma cruzi

2016 ◽  
Vol 22 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Tomás Nepomuceno-Mejía ◽  
Reyna Lara-Martínez ◽  
Roberto Hernández ◽  
María de Lourdes Segura-Valdez ◽  
Luis F. Jiménez-García
Keyword(s):  
Cell Division ◽  
Trypanosoma Cruzi ◽  
Ethylenediaminetetraacetic Acid ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Light And Electron Microscopy ◽  
Nucleolar Organizer ◽  
Nuclear Bodies ◽  
Nucleolar Organizer Regions ◽  
Nucleolar Material

AbstractNucleolar assembly is a cellular event that requires the synthesis and processing of ribosomal RNA, in addition to the participation of pre-nucleolar bodies (PNBs) at the end of mitosis. In mammals and plants, nucleolar biogenesis has been described in detail, but in unicellular eukaryotes it is a poorly understood process. In this study, we used light and electron microscopy cytochemical techniques to investigate the distribution of nucleolar components in the pathway of nucleolus rebuilding during closed cell division in epimastigotes of Trypanosoma cruzi, the etiologic agent of American trypanosomiasis. Silver impregnation specific for nucleolar organizer regions and an ethylenediaminetetraacetic acid regressive procedure to preferentially stain ribonucleoprotein revealed the conservation and dispersion of nucleolar material throughout the nucleoplasm during cell division. Furthermore, at the end of mitosis, the argyrophilic proteins were concentrated in the nucleolar organizer region. Unexpectedly, accumulation of nucleolar material in the form of PNBs was not visualized. We suggest that formation of the nucleolus in epimastigotes of T. cruzi occurs by a process that does not require the concentration of nucleolar material within intermediate nuclear bodies such as mammalian and plant PNBs.

Karyotype evolution and chromosome numbers in Chrysopsis (Nutt.) Ell. sensu Semple (Compositae–Astereae)

1980 ◽  
Vol 58 (2) ◽  
pp. 164-171 ◽  
Author(s):  
J. C. Semple ◽  
C. C. Chinnappa
Keyword(s):  
Chromosome Numbers ◽  
Karyotype Evolution ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Acrocentric Chromosomes

The karyotypes of all species of Chrysopsis were analysed and four basic complements were recognised. The X = 5 karyotype was possessed by all seven n = 5 species and consisted of three submetacentric and two acrocentric chromosomes, one bearing the nucleolar organizer region medially on its short arm. Each X = 4 species had a distinct karyotype. The n = 4 karyotype of C. mariana had diverged less from the X = 5 karyotype than that of C. pilosa. The X2 = 9 karyotype shared by three n = 9 taxa was found to be little more than a combination of the X = 5 karyotype and the X = 4 mariana karyotype and was therefore of allopolyploid origin. Some shifting in the location of the nucleolar organizer region has occurred in each group.

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