scholarly journals The First Chromosome Analysis and Localization of the Nucleolar Organizer Region of Phayre's Flying Squirrel, Hylopetes phayrei (Rodentia, Sciuridae) in Thailand

CYTOLOGIA ◽  
2014 ◽  
Vol 79 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Sitthisak Jantarat ◽  
Sumpars Khunsook ◽  
Praween Supanuam ◽  
Somsak Jeewattana ◽  
Sarawut Kaewsri ◽  
...  
Keyword(s):  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Chromosome Analysis ◽  
Flying Squirrel

Studies of the X chromosome of Anopheles albimanus

1985 ◽  
Vol 27 (1) ◽  
pp. 74-82
Author(s):  
J. A. Seawright ◽  
M. Q. Benedict ◽  
S. Narang
Keyword(s):  
X Chromosome ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Chromosome Analysis ◽  
Anopheles Albimanus ◽  
Eye Color ◽  
Colour Mutant ◽  
Translocation Breakpoints ◽  
Radiation Induced

Snow (sn) is a recessive, eye color mutant that is phenotypically indistinguishable from the previously described mutant, white eye (we). The loci for these mutants are over 30 map units apart on the X chromosome. Analysis of salivary gland chromosomes of radiation-induced X-autosome translocations were used to define the positions of sn and we on the distal euchromatic portion of the long arm of the X chromosome. A recessive lethal trait (bubble head) was also mapped relative to we and sn, and the gene order on the long arm of the X chromosome is as follows: centromere – ? – snow – bubble head – white eye. Translocation breakpoints in the euchromatic portion of the X chromosome caused sterility or lethality in males hemizygous for the translocations, but breaks in the heterochromatin had no effect. Crossing-over was greatly reduced when translocation breakpoints were located in the euchromatic part of the X chromosome. The translocations were used to determine that the nucleolar organizer region is probably on the short arm of the X chromosome.Key words: Anopheles albimanus, eye colour mutant, X chromosome.

scholarly journals First chromosome analysis of Thai pufferfish Pao cochinchinensis (Steindachner, 1866)

2020 ◽  
Vol 21 (9) ◽  
Author(s):  
MANACHAYA PISSAPARN ◽  
SUMALEE PHIMPHAN ◽  
PATCHARAPORN CHAIYASAN ◽  
ALONGKLOD TANOAMTONG ◽  
THOMAS LIEHR ◽  
...  
Keyword(s):  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Molecular Cytogenetics ◽  
Nucleolar Organizer ◽  
Chromosome Analysis ◽  
Chromosomal Evolution ◽  
Giemsa Staining ◽  
Heteromorphic Sex Chromosomes ◽  
Almost All

Abstract. Pissaparn M, Phimphan S, Chaiyasan P, Tanoamtong A, Liehr T, Suwannapoom C, Reungsing M, Supiwong W. 2020. First chromosome analysis of Thai pufferfish Pao cochinchinensis (Steindachner, 1866). Biodiversitas 21: 4309-4316. Here first analysis of chromosomes and nucleolar organizer region (NOR) pattern in pufferfish Pao cochinchinensis (Steindachner, 1866) was undertaken. Chromosomal preparations were obtained from kidney of P. cochinchinensis from Chi River basin in Thailand. Chromosomal characteristics were analyzed by Giemsa staining, Ag-NOR banding as well as fluorescence in situ hybridization (FISH) using microsatellites d(CA)15 and d(CGG)10 probes. P. cochinchinensis had 2n = 40 with the fundamental number (NF) 74, both in male and female. The karyotype exhibited 12 metacentric (m), 10 submetacentric (sm), 12 acrocentric (a) and 6 telocentric (t) chromosomes. No differentiated heteromorphic sex chromosomes were observed. NORs were located on short arms adjacent to telomere of the metacentric chromosome pair 4, which coincide with signals of d(CGG)10 probe. FISH with d(CGG)10 sequences were also displayed at the telomeres of most other chromosomes, whereas d(CA)15 repeats highly accumulated throughout almost all entire chromosomes except for centromeric regions. The results of conventional Giemsa staining presented the differentiation even the same genus. The localization of NORs on one pair of chromosomes only is a common characteristic found in many fish groups as well as other vertebrates. Mapping of two distinct microsatellites demonstrated the remarkable chromosomal diversification that characterizes evolution in the genus Pao. Both, conventional and molecular cytogenetics are excellent tools to study, and better understand chromosomal evolution, as well as to uncover biodiversity among fishes.

scholarly journals First Chromosome Analysis and Localization of the Nucleolar Organizer Region of Land Snail, Sarika resplendens (Stylommatophora, Ariophantidae) in Thailand

CYTOLOGIA ◽  
2013 ◽  
Vol 78 (3) ◽  
pp. 213-222 ◽  
Author(s):  
Wilailuk Khrueanet ◽  
Weerayuth Supiwong ◽  
Chanidaporn Tumpeesuwan ◽  
Sakboworn Tumpeesuwan ◽  
Krit Pinthong ◽  
...  
Keyword(s):  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Chromosome Analysis ◽  
Land Snail

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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