Chromosome banding in salmonid fishes: nucleolar organizer regions in Oncorhynchus

1986 ◽  
Vol 28 (4) ◽  
pp. 502-510 ◽  
Author(s):  
Ruth B. Phillips ◽  
Kerry D. Zajicek ◽  
Fred M. Utter
Keyword(s):  
Chromosome Pair ◽  
Chromosome Banding ◽  
Acrocentric Chromosome ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Salmonid Fishes ◽  
Chromomycin A3 ◽  
Banding Patterns ◽  
Submetacentric Chromosome ◽  
Single Chromosome

Chromosome banding patterns obtained by silver staining and chromomycin a3 (CMA3) staining were analyzed in six species of Oncorhynchus: O. tshawytscha, O. kisutch, O. keta, O. nerka, and O. gorbuscha from North America and O. masou from Japan. Four different chromosomal locations of the nucleolor organizer regions (NORs) were found in different species. In O. tshawytscha, O. kisutch, and O. masou the NORs comprised the entire short arms of one medium-sized acrocentric chromosome pair. In O. nerka the NORs were found in an interstitial band on the short arms of one submetacentric chromosome pair and in O. gorbuscha proximal to the centromere on one metacentric chromosome pair. In O. keta the NORs were found on the telomeres of one small submetacentric chromosome pair. As in the related genera Salmo and Salvelinus chromomycin A3 positive bands were found at the same sites as the AgNORs in all species. Salmonid fish are assumed to be ancestral tetraploids and the considerable differences in chromosome number between different species are thought to be the result of chromosomal fusions after tetraploidization. In all members of the genus Oncorhynchus the rearrangements have resulted in the consolidation of the NORs on a single chromosome pair. The possible significance of intra- and inter-species NOR polymorphisms is discussed.Key words: nucleolar organizer regions, salmon, Oncorhynchus, chromosomes.

Chromosome banding in salmonid fish: nucleolar organizer regions in Salmo and Salvelinus

1985 ◽  
Vol 27 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Ruth Phillips ◽  
Peter E. Ihssen
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Brook Trout ◽  
Chromosome Banding ◽  
Lake Trout ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Banding Patterns ◽  
Single Chromosome ◽  
Secondary Constrictions

Chromosome banding patterns obtained by silver staining (Ag-NORs) were analyzed in three species of Salmo (rainbow, brown trout, and Atlantic salmon) and three species of Salvelinus (brook trout, lake trout, and arctic char). In rainbow trout and Atlantic salmon the Ag-NORs were found at the secondary constrictions of a single chromosome pair, while in brown trout the Ag-NORs were found on the short arms of one or two of the two longest subtelocentric or acrocentric chromosome pairs. The location of the Ag-NORs was multichromosomal in the three Salvelinus species, occurring on one or both members of four to six different chromosome pairs in different individuals. The Ag-NOR sites were on the short arms of some acrocentric pairs and at the telomeres of other acrocentric pairs and one or two metacentric pairs. Chromomycin A3 positive bands were found at the same sites as the Ag-NORs in all species. In the species with multichromosomal location of Ag-NORs, polymorphisms in the size and location of the NORs were extremely common, so that almost every individual fish had a different pattern of Ag-NOR sites.Key words: banding, Salmo, Salvelinus, Ag-NORs, polymorphisms, nucleolar organizer.

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.

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.

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.

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 Chromosome Banding in Amphibia. XXXII. The Genus Xenopus (Anura, Pipidae)

2015 ◽  
Vol 145 (3-4) ◽  
pp. 201-217 ◽  
Author(s):  
Michael Schmid ◽  
Claus Steinlein
Keyword(s):  
Chromosome Pair ◽  
Repetitive Sequences ◽  
5S Rdna ◽  
Mitotic Chromosomes ◽  
Banding Patterns ◽  
Single Chromosome ◽  
Replication Banding ◽  
Rdna Sequences ◽  
High Degree ◽  
Replication Bands

Mitotic chromosomes of 16 species of the frog genus Xenopus were prepared from kidney and lung cell cultures. In the chromosomes of 7 species, high-resolution replication banding patterns could be induced by treating the cultures with 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT) in succession, and in 6 of these species the BrdU/dT-banded chromosomes could be arranged into karyotypes. In the 3 species of the clade with 2n = 20 and 4n = 40 chromosomes (X. tropicalis, X. epitropicalis, X. new tetraploid 1), as well as in the 3 species with 4n = 36 chromosomes (X. laevis, X. borealis, X. muelleri), the BrdU/dT-banded karyotypes show a high degree of homoeology, though differences were detected between these groups. Translocations, inversions, insertions or sex-specific replication bands were not observed. Minor replication asynchronies found between chromosomes probably involve heterochromatic regions. BrdU/dT replication banding of Xenopus chromosomes provides the landmarks necessary for the exact physical mapping of genes and repetitive sequences. FISH with an X. laevis 5S rDNA probe detected multiple hybridization sites at or near the long-arm telomeric regions in most chromosomes of X. laevis and X. borealis, whereas in X. muelleri, the 5S rDNA sequences are located exclusively at the long-arm telomeres of a single chromosome pair. Staining with the AT base pair-specific fluorochrome quinacrine mustard revealed brightly fluorescing heterochromatic regions in the majority of X. borealis chromosomes which are absent in other Xenopus species.

scholarly journals Physical and Genetic Mapping in the GrassesLolium perenneandFestuca pratensis

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 315-324 ◽  
Author(s):  
J King ◽  
I P Armstead ◽  
I S Donnison ◽  
H M Thomas ◽  
R N Jones ◽  
...  
Keyword(s):  
Large Scale ◽  
Physical Map ◽  
Rice Chromosome ◽  
Nucleolar Organizer ◽  
Physical Distance ◽  
Chromosome 1 ◽  
Grass Species ◽  
Nucleolar Organizer Regions ◽  
Single Chromosome ◽  
Large Scale Analysis

AbstractA single chromosome of the grass species Festuca pratensis has been introgressed into Lolium perenne to produce a diploid monosomic substitution line (2n = 2x = 14). In this line recombination occurs throughout the length of the F. pratensis/L. perenne bivalent. The F. pratensis chromosome and recombinants between it and its L. perenne homeologue can be visualized using genomic in situ hybridization (GISH). GISH junctions represent the physical locations of sites of recombination, enabling a range of recombinant chromosomes to be used for physical mapping of the introgressed F. pratensis chromosome. The physical map, in conjunction with a genetic map composed of 104 F. pratensis-specific amplified fragment length polymorphisms (AFLPs), demonstrated: (1) the first large-scale analysis of the physical distribution of AFLPs; (2) variation in the relationship between genetic and physical distance from one part of the F. pratensis chromosome to another (e.g., variation was observed between and within chromosome arms); (3) that nucleolar organizer regions (NORs) and centromeres greatly reduce recombination; (4) that coding sequences are present close to the centromere and NORs in areas of low recombination in plant species with large genomes; and (5) apparent complete synteny between the F. pratensis chromosome and rice chromosome 1.

scholarly journals Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5316 ◽  
Author(s):  
Naiara Pereira Araújo ◽  
Cayo Augusto Rocha Dias ◽  
Rodolfo Stumpp ◽  
Marta Svartman
Keyword(s):  
Chromosome Mapping ◽  
Nucleolar Organizer ◽  
Interspecific Variation ◽  
Nucleolar Organizer Regions ◽  
45S Rdna ◽  
Banding Patterns ◽  
Pericentric Inversions ◽  
Cytogenetic Analyses ◽  
First Time

Trinomys Thomas (1921) is a terrestrial genus of spiny rats endemic to the Brazilian areas of Atlantic Forest and the transitional areas of Cerrado and Caatinga. Although most species have been already karyotyped, the available cytogenetic information is mostly restricted to diploid and fundamental numbers. We analyzed the chromosomes of two Trinomys species: Trinomys moojeni (2n = 56, FN = 106) and Trinomys setosus setosus (2n = 56, FN = 106 and 2n = 56, FN = 108). Our analyses included GTG- and CBG-banding, silver-staining of the nucleolar organizer regions, and chromosome mapping of telomeres and 45S rDNA by fluorescent in situ hybridization (FISH). Comparative GTG- and CBG-banding suggested that the interspecific variation may be due to rearrangements such as pericentric inversions, centromere repositioning, and heterochromatin variation. We report two new karyotypes for T. s. setosus and describe for the first time the banding patterns of the two Trinomys species.

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