scholarly journals First Report on Nucleolar Organizer Regions (NORs) Polymorphism and Constitutive Heterochromatin of Moonlight Gourami, Trichopodus microlepis (Perciformes, Osphronemidae)

Caryologia ◽  
2021 ◽  
Author(s):  
Weerayuth Supiwong
Keyword(s):  
Chromosome Pair ◽  
Constitutive Heterochromatin ◽  
Sex Chromosome ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Mitotic Chromosomes ◽  
First Report ◽  
Telocentric Chromosomes ◽  
Karyotype Formula ◽  
Males And Females

Nucleolar organizer regions (NORs) polymorphism, constitutive heterochromatin and chromosomal analysis of Moonlight gourami, Trichopodus microlepis in Thailand were firstly reported. Specimens were collected from the Chao Phraya and Mekong Basins, Thailand. The mitotic chromosomes were directly prepared from kidney tissues of ten males and ten females. Conventional staining, Ag-NOR banding and C- banding techniques were applied to stain the chromosomes. The results shown that the diploid chromosome number of T. microlepis was 2n=46 and the fundamental number (NF) was 46 in both males and females. The karyotype consisted of 46 telocentric chromosomes classifying as 14 large and 32 medium. No heteromorphic sex chromosome was observed in T. microlepis. The results also exhibited that the interstitial nucleolar organizer regions (NORs) were clearly observed at the long arm of the chromosome pair 7. This is the first report on NORs polymorphism in T. microlepis that a heteromorphic NOR type in one female had a single NOR-bearing chromosome of the chromosome pair 7, whereas 10 males and nine females had two NOR-bearing chromosomes of the chromosome pair 7 with a homomorphic NOR type. Constitutive heterochromatins located at all centromeres of all chromosome pairs. The karyotype formula of T. microlepis is 2n (46) = Lt14 + Mt32.

scholarly journals First report of karyological analysis and heteromorphic nucleolar organizer region of Black Surgeonfish (Acanthurus gahhm, Acanthuridae) in Thailand

Caryologia ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 83-88
Author(s):  
Sitthisak Jantarat ◽  
Sarun Jumrusthanasan ◽  
Sarawut Kaewsri ◽  
Praween Supanuam ◽  
Alongklod Tanomtong
Keyword(s):  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Andaman Sea ◽  
Nucleolar Organizer Regions ◽  
Mitotic Chromosomes ◽  
Karyological Analysis ◽  
First Report ◽  
Telocentric Chromosomes ◽  
Karyotype Formula

This research was the first report on karyological analysis and heteromorphic nucleolar organizer region of black surgeonfish (Acanthurus gahhm, Acanthuridae) in Thailand. The 10 male and 10 female specimens were collected from Phuket Marine Biological Center, and Phang Nga Coastal Research and Development Center, Andaman Sea, Thailand. Mitotic chromosomes were directly prepared from gill and kidney tissues. The chromosomes were stained by conventional Giemsa staining and Ag-NOR banding techniques. Results showed that the diploid chromosomes number of A. gahhm was 2n=48, the fundamental numbers (NF) was 54 in both male and female. The karyotype consist of 6 large acrocentric, 20 large telocentric, 18 medium telocentric and 4 small telocentric chromosomes. None of strange size chromosomes related to sex was found. The heteromorphic nucleolar organizer regions (NORs) were observed on telomeric short arm of first acrocentric which can defined as 1a1b. There is NOR in 1a and not in 1b. The karyotype formula of black surgeon fish was as follows: 2n (48) = La6+Lt20+Mt18+St4

Structure and variability of nucleolar organizer regions in Parodontidae fish

1984 ◽  
Vol 26 (5) ◽  
pp. 564-568 ◽  
Author(s):  
Orlando Moreira-Filho ◽  
Luiz Antonio Carlos Bertollo ◽  
Pedro Manoel Galetti Jr.
Keyword(s):  
Chromosome Pair ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Mitotic Chromosomes ◽  
Homozygous Condition ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Chromosome

Nucleolar organizer regions (NORs) were studied in mitotic chromosomes of four species of fish of family Parodontidae: Parodon tortuosus, Apareiodon affinis, Apareiodon ibitiensis, and Apareiodon piracicabae. All four species exhibited only a single nucleolar chromosome pair in their karyotypes. Intraspecific differences were observed in the size of these chromosomes; however, these were not very clear for A. affinis and A. piracicabae, Apareiodon piracicabae exhibited two clearly visible NORs in each of the nucleolar chromosomes, which was the only configuration practically found in this species. This trait therefore predominates in a homozygous condition in the population investigated. Regions of constitutive heterochromatin adjacent to the two NORs were detected. Possible mechanisms that may have originated the two NORs are discussed.Key words: nucleolar organizing regions, fish.

Constitutive heterochromatin DNA polymorphisms in diploid Medicago sativa ssp. falcata

Genome ◽  
1999 ◽  
Vol 42 (5) ◽  
pp. 930-935 ◽  
Author(s):  
G R Bauchan ◽  
M A Hossain
Keyword(s):  
Medicago Sativa ◽  
Banding Pattern ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Dna Polymorphisms ◽  
Banding Technique ◽  
Chromosome 3 ◽  
Nucleolar Organizer Regions ◽  
First Report ◽  
C Banding

A Giemsa C-banding technique was used to study the amount and location of constitutive heterochromatin in diploid (2n = 2x = 16) Medicago sativa ssp. falcata (L.) Arcangeli. Most accessions had the standard C-banding pattern with centromeric bands on all the chromosomes and a prominent heterochromatic band at the nucleolar organizer regions (NOR) of the satellited (SAT) chromosomes. However, we observed in various accessions that constitutive heterochromatic C-bands can exist at the telomeric ends of all the chromosomes. Interstitial bands occurred on the short arms of all chromosomes except for chromosome 3 and on the long arms of chromosomes 1, 2, 3, and 6, only. Rearranged chromosomes such as isochromosomes have been observed for the short arms of chromosomes 2 and 6. This is the first report on the existence of C-banding polymorphisms and the detection of putative isochromsomes in the chromosomes of diploid ssp. falcata which could have contributed to the variation observed in cultivated alfalfa.Key words: alfalfa, C-bands, chromosome, isochromosome.

scholarly journals Comparative cytogenetic study in Muscidae flies

2007 ◽  
Vol 67 (4 suppl) ◽  
pp. 945-950 ◽  
Author(s):  
PP. Parise-Maltempi ◽  
RMP. Avancini
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Pair ◽  
Sex Chromosome ◽  
Cytogenetic Study ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Modal Number ◽  
The Relationship

The chromosome modal number in Muscoidea Diptera is 2n = 12, including five pairs of autosomes and one sex chromosome pair. Nevertheless, some species with 2n = 10 chromosomes have been described, all of them from the Muscidae family. We analyzed the karyotype of some Muscidae species from different subfamilies and compared the obtained data with the karyotypes of some species of the families Calliphoridae and Sarcophagidae. Comparisons of these species with other Muscidae species revealed a considerable variation among their sex chromosomes. This variation in the length of the sex chromosomes suggests that parts of these chromosomes were lost or fused with autosomes. The constitutive heterochromatic regions and the nucleolar organizer regions (NORs) were also analyzed and some aspects about the relationship between these regions and the sex chromosomes are discussed.

scholarly journals Karyotypes of four species of Xenodontini snakes (Serpentes) and implications for taxonomy

2016 ◽  
Vol 85 (3) ◽  
pp. 265-273 ◽  
Author(s):  
Camila Falcione ◽  
Alejandra Hernando ◽  
Diego Andrés Barrasso ◽  
Diego Omar Di Pietro
Keyword(s):  
Chromosome Pair ◽  
Sex Chromosome ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Submetacentric Chromosome ◽  
Molecular Phylogenetic Tree ◽  
Molecular Phylogenetic ◽  
Karyological Data ◽  
First Time ◽  
Northeastern Argentina

The karyotypes of four Xenodontini snake species, Lygophis dilepis, L. meridionalis, L. flavifrenatus and L. anomalus, are here described for the first time. We studied specimens from northeastern Argentina using conventional and silver (Ag-NOR) staining. While the typical ophidian karyotype is 2n = 36, we found that the karyotype of the studied species is 2n = 34, with metacentric and submetacentric chromosome pairs. The 4th NOR staining revealed that nucleolar organizer regions (NORs) are located on one pair of microchromosomes. In L. dilepis and L. anomalus the 4th chromosome pair is heteromorphic, and we suggest that it might be considered as the ZW sex chromosome pair. The optimization of available karyological data on a molecular phylogenetic tree of the tribe Xenodontini shows that the diploid numbers 2n = 28, 30 and 34 represent putative synapomorphy for Erythrolamprus, Xenodon and Lygophis, respectively. Our results provide new insights which fill gaps in our knowledge on the cytology in the genus Lygophis and identified a possible diagnostic character for the genus.

The mitotically phosphorylated form of the transcription termination factor TTF-1 is associated with the repressed rDNA transcription machinery

1999 ◽  
Vol 112 (19) ◽  
pp. 3259-3268 ◽  
Author(s):  
V. Sirri ◽  
P. Roussel ◽  
D. Hernandez-Verdun
Keyword(s):  
Transcription Termination ◽  
Nucleolar Organizer ◽  
Ribosomal Gene ◽  
Nucleolar Organizer Regions ◽  
Rdna Transcription ◽  
Mitotic Chromosomes ◽  
Termination Factor ◽  
Transcription Machinery ◽  
Phosphorylated Form ◽  
Transcription Termination Factor

The transcription termination factor TTF-1 exerts two functions in ribosomal gene (rDNA) transcription: facilitating initiation and mediating termination of transcription. Using HeLa cells, we show that TTF-1 protein is colocalized with the active transcription machinery in the nucleolus and also with the inactive machinery present in certain mitotic nucleolar organizer regions (NORs) when rDNA transcription is repressed. We also show that TTF-1 is specifically phosphorylated during mitosis in a manner dependent on the cdc2-cyclin B kinase pathway and on an okadaic acid-sensitive phosphatase. Interestingly, the mitotically phosphorylated form of TTF-1 appearing at the G(2)/M transition phase was more easily solubilized than was the interphase form. This indicates that the chromatin-binding affinity of TTF-1 appears to be different in mitotic chromosomes compared to the interphase nucleolus. Correlated with this, the other DNA-binding factor, UBF, which interferes with chromatin conformation in the rDNA promoter, was more strongly bound to rDNA during mitosis than at interphase. The reorganization of the mitotic rDNA promoter might be induced by phosphorylation of certain components of the rDNA transcription machinery and participate in silencing of rDNA during mitosis.

scholarly journals Cytogenetical analyses in three fish species of the genus Pimelodus(Siluriformes: Pimelodidae) from rio São Francisco: considerations about the karyotypical evolution in the genus

2005 ◽  
Vol 3 (2) ◽  
pp. 285-290 ◽  
Author(s):  
Caroline Garcia ◽  
Orlando Moreira Filho
Keyword(s):  
Chromosome Pair ◽  
Chromosomal Rearrangements ◽  
Nucleolar Organizer ◽  
Differential Staining ◽  
Nucleolar Organizer Regions ◽  
C Banding ◽  
Heteromorphic Sex Chromosomes ◽  
Chromosomal Markers ◽  
Staining Techniques ◽  
Species Specific

Karyotypes and other chromosomal markers were investigated in three species of the catfish genus Pimelodus, namely P. fur, P. maculatus and Pimelodus sp., from municipality of Três Marias, Minas Gerais, Brazil, using differential staining techniques (C-banding, Silver nitrate and CMA3 staining). The diploid chromosome number was 2n = 56 in P. maculatus and Pimelodus sp., while in P. fur 2n = 54. The karyotype of P. fur consisted in 32M + 8SM + 6ST + 8A with fundamental number (NF) of 100, that of P. maculatus 32M + 12SM + 12A with NF = 112, and that of Pimelodus sp. had 32M + 12Sm + 6ST + 6A with NF = 106.The nucleolar organizer regions (NORs) in all three species were invariably detected in telomeres of longer arm of the 20th chromosome pair. These sites were also positive after CMA3 and C-banding. No heteromorphic sex chromosomes were detected and C-banding pattern was species specific. Inferences about the karyotype differentiation in Pimelodus and putative chromosomal rearrangements are hypohesized.

scholarly journals Cytogenetics of the neotropical flesh fly Pattonela intermutans (Diptera, Sarcophagidae)

2000 ◽  
Vol 23 (3) ◽  
pp. 563-567 ◽  
Author(s):  
Patricia Pasquali Parise-Maltempi ◽  
Rita Maria Pereira Avancini
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Pair ◽  
Sex Chromosome ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Pericentromeric Region ◽  
Flesh Fly ◽  
Fish Technique

Pattonella intermutans has 2n = 12 chromosomes including three metacentric and two submetacentric pairs of autosomes and an XX/XY sex chromosome pair. The autosomes are characterized by the presence of a C band in the pericentromeric region while sex chromosomes are totally heterochromatic. The FISH technique showed a nucleolar organizer region (NOR) in autosome IV.

Chromosome differentiation in the subantarctic Bovichtidae species Cottoperca gobio (Günther, 1861) and Pseudaphritis urvillii (Valenciennes, 1832) (Pisces, Perciformes)

1995 ◽  
Vol 7 (4) ◽  
pp. 381-386 ◽  
Author(s):  
Eva Pisano ◽  
C. Ozouf-Costaz ◽  
J-C. Hureau ◽  
R. Williams
Keyword(s):  
Constitutive Heterochromatin ◽  
Chromosomal Location ◽  
Cytogenetic Study ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Chromosome Differentiation ◽  
Fundamental Number ◽  
Magellan Strait ◽  
Australian Plate ◽  
Acrocentric Chromosomes

A cytogenetic study on the bovichtid species Cottoperca gobio from the Magellan Strait and Pseudaphritis urvillii from Tasmania showed both species have a plesiomorphic number of chromosomes (2n=48). However, C.gobio has a more conservative karyotype composed entirely of acrocentric chromosomes (Fundamental Number=48); the presence of two metacentric pairs in P. urvilli (FN=52) makes this species karyologically more derived. The differences in the number of chromosomal arms, and the chromosomal location of the nucleolar organizer regions indicate karyological divergence in the two separating stocks from which C.gobio and P.urvillii originated. During the diversification of this notothenioid family, probably coincident with the fragmentation of Gondwana, the stock that split off with the Australian Plate gave rise to the Tasmanian species and experienced more chromosomal modifications than the stock from which C. gobio is derived. The pattern of constitutive heterochromatin suggests a possible homology between a pair of chromosomes in bovichtids and other notothenioids.

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