Evolutionary Relationships among Boulengerella Species (Ctenoluciidae, Characiformes): Genomic Organization of Repetitive DNAs and Highly Conserved Karyotypes

2017 ◽  
Vol 152 (4) ◽  
pp. 194-203 ◽  
Author(s):  
José F. de Souza e Sousa ◽  
Patrik F. Viana ◽  
Luiz A.C. Bertollo ◽  
Marcelo B. Cioffi ◽  
Eliana Feldberg
Keyword(s):  
18S Rdna ◽  
Sex Chromosome ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Rrna Genes ◽  
Fish Family ◽  
Telomeric Sequences ◽  
5S Rrna Genes ◽  
Species Specific

Ctenoluciidae is a Neotropical freshwater fish family whose representatives are known as bicudas. The genus Boulengerella contains 5 species, and 4 of them (B. cuvieri, B. lateristriga, B. lucius, and B. maculata) were cytogenetically analyzed in the present study by conventional and molecular procedures. All 4 species have a very similar karyotype, with 2n = 36 chromosomes (14 metacentrics + 16 submetacentrics + 6 subtelocentrics; FN = 72). However, the heterochromatin distribution pattern is species-specific. In all 4 species, the nucleolus organizer region is located in pair 18, as also confirmed by cytogenetic mapping of 18S rDNA. In turn, 5S rRNA genes are present in 2 chromosome pairs: in pair 1 of all 4 species, and in pair 10 of B. lateristriga, B. maculata, and B. cuvieri, but in pair 4 of B. lucius. The telomeric probe highlighted terminal regions in all chromosomes, as well as an interstitial centromeric sequence in pair 3 of the 3 first-mentioned species. Notably, a conspicuous heteromorphic secondary constriction in chromosomes 18 was found only in the males of the 3 species, rendering one of the homologs much larger than the other one. This feature, associated with a large 18S rDNA block and accumulation of telomeric sequences, suggests the presence of an XX/XY sex chromosome system in the analyzed Boulengerella species.

scholarly journals Interspecific cytogenetic relationships in three Acestrohynchus species (Acestrohynchinae, Characiformes) reveal the existence of possible cryptic species

2020 ◽  
Vol 14 (1) ◽  
pp. 27-42
Author(s):  
Alber Sousa Campos ◽  
Ramon Marin Favarato ◽  
Eliana Feldberg
Keyword(s):  
Chromosome Pair ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
5S Rdna ◽  
Nucleolus Organizer ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Rdna Sites ◽  
Species Specific

The karyotypes and chromosomal characteristics of three Acestrorhynchus Eigenmann et Kennedy, 1903 species were examined using conventional and molecular protocols. These species had invariably a diploid chromosome number 2n = 50. Acestrorhynchus falcatus (Block, 1794) and Acestrorhynchus falcirostris (Cuvier, 1819) had the karyotype composed of 16 metacentric (m) + 28 submetacentric (sm) + 6 subtelocentric (st) chromosomes while Acestrorhynchus microlepis (Schomburgk, 1841) had the karyotype composed of 14m+30sm+6st elements. In this species, differences of the conventional and molecular markers between the populations of Catalão Lake (AM) and of Apeu Stream (PA) were found. Thus the individuals of Pará (Apeu) were named Acestrorhynchus prope microlepis. The distribution of the constitutive heterochromatin blocks was species-specific, with C-positive bands in the centromeric and telomeric regions of a number of different chromosomes, as well as in interstitial sites and completely heterochromatic arms. The phenotypes of nucleolus organizer region (NOR) were simple, i. e. in a terminal position on the p arm of pair No. 23 except in A. microlepis, in which it was located on the q arm. Fluorescence in situ hybridization (FISH) revealed 18S rDNA sites on one chromosome pair in karyotype of A. falcirostris and A. prope microlepis (pair No. 23) and three pairs (Nos. 12, 23, 24) in A. falcatus and (Nos. 8, 23, 24) in A. microlepis; 5S rDNA sites were detected in one chromosome pair in all three species. The mapping of the telomeric sequences revealed terminal sequences in all the chromosomes, as well as the presence of interstitial telomeric sequences (ITSs) in a number of chromosome pairs. The cytogenetic data recorded in the present study indicate that A. prope microlepis may be an unnamed species.

scholarly journals Discovery of Putative XX/XY Male Heterogamety in Emydura subglobosa Turtles Exposes a Novel Trajectory of Sex Chromosome Evolution in Emydura

2019 ◽  
Vol 158 (3) ◽  
pp. 160-169 ◽  
Author(s):  
LingSze Lee ◽  
Eugenia E. Montiel ◽  
Nicole Valenzuela
Keyword(s):  
Sex Determination ◽  
Sex Chromosome ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Molecular Cytogenetics ◽  
Nucleolus Organizer ◽  
Model Organisms ◽  
Comparative Genome Hybridization ◽  
Evolutionary Trajectory ◽  
Genotypic Sex Determination

The discovery of sex chromosome systems in non-model organisms has elicited growing recognition that sex chromosomes evolved via diverse paths that are not fully elucidated. Lineages with labile sex determination, such as turtles, hold critical cues, yet data are skewed toward hide-neck turtles (suborder Cryptodira) and scant for side-neck turtles (suborder Pleurodira). Here, we used classic and molecular cytogenetics to investigate Emydura subglobosa (ESU), an unstudied side-neck turtle with genotypic sex determination from the family Chelidae, where extensive morphological divergence exists among XX/XY systems. Our data represent the first cytogenetic description for ESU. Similarities were found between ESU and E. macquarii (EMA), such as identical chromosome number (2n = 50), a single and dimorphic nucleolus organizer region (NOR) localized in a microchromosome pair (ESU14) of both sexes (detected via FISH of 18S rDNA). Only the larger NOR is active (detected by silver staining). As in EMA, comparative genome hybridization revealed putative macro XX/XY chromosomes in ESU (the 4th largest pair). Our comparative analyses and revaluation of previous data strongly support the hypothesis that Emydura's XX/XY system evolved via fusion of an ancestral micro-Y (retained by Chelodina longicollis) onto a macro-autosome. This evolutionary trajectory differs from the purported independent evolution of XX/XY from separate ancestral autosomes in Chelodina and Emydura that was previously reported. Our data permit dating this Y-autosome fusion to at least the split of Emydura around 45 Mya and add critical information about the evolution of the remarkable diversity of sex-determining mechanisms in turtles, reptiles, and vertebrates.

Molecular and cytological characterization of ribosomal RNA genes in Chenopodium quinoa and Chenopodium berlandieri

Genome ◽  
2006 ◽  
Vol 49 (7) ◽  
pp. 825-839 ◽  
Author(s):  
P J Maughan ◽  
B A Kolano ◽  
J Maluszynska ◽  
N D Coles ◽  
A Bonifacio ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Chenopodium Quinoa ◽  
Nucleolus Organizer ◽  
5S Rrna ◽  
Rrna Genes ◽  
Fish Analysis ◽  
General Sequence ◽  
Sequence Composition

The nucleolus organizer region (NOR) and 5S ribosomal RNA (rRNA) genes are valuable as chromosome landmarks and in evolutionary studies. The NOR intergenic spacers (IGS) and 5S rRNA nontranscribed spacers (NTS) were PCR-amplified and sequenced from 5 cultivars of the Andean grain crop quinoa (Chenopodium quinoa Willd., 2n = 4x = 36) and a related wild ancestor (C. berlandieri Moq. subsp. zschackei (Murr) A. Zobel, 2n = 4x = 36). Length heterogeneity observed in the IGS resulted from copy number difference in subrepeat elements, small re arrangements, and species-specific indels, though the general sequence composition of the 2 species was highly similar. Fifteen of the 41 sequence polymorphisms identified among the C. quinoa lines were synapomorphic and clearly differentiated the highland and lowland ecotypes. Analysis of the NTS sequences revealed 2 basic NTS sequence classes that likely originated from the 2 allopolyploid subgenomes of C. quinoa. Fluorescence in situ hybridization (FISH) analysis showed that C. quinoa possesses an interstitial and a terminal pair of 5S rRNA loci and only 1 pair of NOR, suggesting a reduction in the number of rRNA loci during the evolution of this species. C. berlandieri exhibited variation in both NOR and 5S rRNA loci without changes in ploidy.Key words: rDNA, NOR, IGS, 5S NTS, FISH, Chenopodium.

Genetic control of 1R nucleolus organizer region expression in the presence of wheat genomes

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 713-718 ◽  
Author(s):  
Rita Vieira ◽  
Álvaro Queiroz ◽  
Leonor Morais ◽  
Augusta Barão ◽  
T. Mello-Sampayo ◽  
...  
Keyword(s):  
Genetic Control ◽  
Hexaploid Wheat ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Rrna Genes ◽  
Root Tip ◽  
Region Gene ◽  
Nucleolar Dominance ◽  
Chromosome 1R

The expression of rRNA genes located in the nucleolar organizing region (NOR) present on the short arm of chromosome 1R from rye (Secale cereale L.) was examined in several hexaploid (Triticum aestivum L.) and tetraploid wheats (Triticum turgidum L.) containing the entire chromosome 1R from rye (disomic substitution 1B(1R)), its full haploid genome (hexaploid wheat–rye F1 hybrid), or only its short arm translocated to the long arms of wheat chromosomes from the homoeologous group 1 (disomic translocations 1AL/1RS, 1BL/1RS, or 1DL/1RS) or added to the complete hexaploid wheat genotype (monotelosomic addition 1RS). By silver staining and determination of the number of Ag-NORs and the average number of nucleoli per root-tip cell it became apparent that the expression of 1R NORs, in the presence of wheat genomes, depends on the absence of the long arm of rye chromosome 1R. In wheat-rye F1 hybrids and in hexaploid wheat with a disomic substitution 1B(1R), 1R NOR was morphologically absent, even when only one wheat major NOR was present, in contrast with its frequent expression in wheat–rye translocation or addition lines where only its short arm was added. It is suggested that wheat nucleolar dominance over rye as expressed by heterochromatic and silent NOR in 1RS is under a complex genetic control which involves interaction between 1RL and unidentified wheat genes.Key words: 1R nucleolus organizer region, gene activity, amphiplasty.

1R chromosome nucleolus organizer region activation by 5-azacytidine in wheat × rye hybrids

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 707-712 ◽  
Author(s):  
Rita Vieira ◽  
Álvaro Queiroz ◽  
Leonor Morais ◽  
Augusta Barão ◽  
T. Mello-Sampayo ◽  
...  
Keyword(s):  
Triticum Turgidum ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolar Organizer ◽  
Pyrimidine Ring ◽  
Nucleolus Organizer ◽  
Rrna Genes ◽  
Root Tip ◽  
Root Tips ◽  
Nucleolar Dominance

Nucleolar activity was studied in several lines of Triticum aestivum cv. Chinese Spring, Triticum turgidum cv. Durum, and F1 hybrids from euploid and aneuploid lines of T. aestivum and Secale cereale cv. Centeio do Alto, in cells from root tips of seeds germinated in water or in 5-azacytidine. 5-Azacytidine, an analog of cytidine modified in the 5 position of the pyrimidine ring, inhibits DNA methylation. By using silver staining to determine the number of nucleolus organizer regions and the average number of nucleoli per root-tip cell from seeds germinated in both situations, it became apparent that the presence of 5-azacytidine during germination allowed for the expression of the nucleolus organizer region locus belonging to the rye genome, in contrast to the usual observed cytological absence of the rye nucleolus organizer region in wheat–rye hybrids. It is suggested that wheat nucleolar dominance in wheat–rye hybrids is mainly a consequence of methylation of rRNA genes or its regulators located on the 1R chromosome of rye.Key words: 1R nucleolar organizer, wheat–rye hybrids, methylation, Ag-NOR.

scholarly journals Cytogenetic characterization of Hypostomus soniae Hollanda-Carvalho & Weber, 2004 from the Teles Pires River, southern Amazon basin: evidence of an early stage of an XX/XY sex chromosome system

2019 ◽  
Vol 13 (4) ◽  
pp. 411-422 ◽  
Author(s):  
Luciene Castuera de Oliveira ◽  
Marcos Otávio Ribeiro ◽  
Gerlane de Medeiros Costa ◽  
Cláudio Henrique Zawadzki ◽  
Ana Camila Prizon-Nakajima ◽  
...  
Keyword(s):  
Amazon Basin ◽  
Sex Chromosome ◽  
Early Stage ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Structural Difference ◽  
Chromosomal Polymorphism ◽  
Nucleolus Organizer ◽  
Rdna Sites ◽  
Sex Chromosome System

In the present study, we analyzed individuals of Hypostomus soniae (Loricariidae) collected from the Teles Pires River, southern Amazon basin, Brazil. Hypostomus soniae has a diploid chromosome number of 2n = 64 and a karyotype composed of 12 metacentric (m), 22 submetacentric (sm), 14 subtelocentric (st), and 16 acrocentric (a) chromosomes, with a structural difference between the chromosomes of the two sexes: the presence of a block of heterochromatin in sm pair No. 26, which appears to represent a putative initial stage of the differentiation of an XX/XY sex chromosome system. This chromosome, which had a heterochromatin block, and was designated proto-Y (pY), varied in the length of the long arm (q) in comparison with its homolog, resulting from the addition of constitutive heterochromatin. It is further distinguished by the presence of major ribosomal cistrons in a subterminal position of the long arm (q). The Nucleolus Organizer Region (NOR) had different phenotypes among the H. soniae individuals in terms of the number of Ag-NORs and 18S rDNA sites. The origin, distribution and maintenance of the chromosomal polymorphism found in H. soniae reinforced the hypothesis of the existence of a proto-Y chromosome, demonstrating the rise of an XX/XY sex chromosome system.

scholarly journals Satellite DNA Mapping in Pseudis fusca (Hylidae, Pseudinae) Provides New Insights into Sex Chromosome Evolution in Paradoxical Frogs

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 160
Author(s):  
Kaleb Gatto ◽  
Karin Seger ◽  
Paulo Garcia ◽  
Luciana Lourenço
Keyword(s):  
Satellite Dna ◽  
Chromosome Evolution ◽  
Common Ancestor ◽  
Sex Chromosome ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Undescribed Species ◽  
The Common

In the frog genus Pseudis, previous works found a sex-linked heteromorphism of the PcP190 satellite DNA in the nucleolus organizer region (NOR)-bearing chromosome pairs of Pseudis bolbodactyla and Pseudis tocantins, which possess a ZZ/ZW sex determination system. A pericentromeric inversion was inferred to have occurred during W chromosome evolution, moving a chromosomal cluster enriched by the PcP190 from the short arm (as observed in P. bolbodactyla) to the NOR-bearing long arm (as observed in P. tocantins). However, whether such an inversion happened in P. tocantins or in the common ancestor of Pseudis fusca and P. tocantins remained unclear. To assess this question, we mapped PcP190 in the karyotype of P. fusca from three distinct localities. Southern blotting was used to compare males and females. The mitochondrial H1 fragment (which contains the 12S ribosomal RNA (rRNA), tRNAval, and 16S rRNA genes) and cytochrome b gene were partially sequenced, and a species tree was inferred to guide our analysis. Pseudis fusca specimens were placed together as the sister group of P. tocantins, but based on genetic distance, one of the analyzed populations is probably an undescribed species. A cluster of PcP190, located in the long arm of chromosome 7, is sex linked in this putative new species but not in the remaining P. fusca. We could infer that the pericentromeric inversion that moved the PcP190 site to the NOR-bearing chromosome arm (long arm) occurred in the common ancestor of P. fusca, the putative undescribed species, and P. tocantins.

scholarly journals Holocentric Chromosomes of Luzula elegans Are Characterized by a Longitudinal Centromere Groove, Chromosome Bending, and a Terminal Nucleolus Organizer Region

2011 ◽  
Vol 134 (3) ◽  
pp. 220-228 ◽  
Author(s):  
S. Heckmann ◽  
E. Schroeder-Reiter ◽  
K. Kumke ◽  
L. Ma ◽  
K. Nagaki ◽  
...  
Keyword(s):  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Holocentric Chromosomes

Mapping of the nucleolus organizer region on chromosome 4 inArabidopsis thaliana

1996 ◽  
Vol 250 (1) ◽  
pp. 123-128
Author(s):  
Georg Haberer ◽  
Thilo C. Fischer ◽  
Ramón A. Torres-Ruiz
Keyword(s):  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Chromosome 4

Hybrid ape offspring of a mating of gibbon and siamang

Science ◽  
1979 ◽  
Vol 205 (4403) ◽  
pp. 308-310 ◽  
Author(s):  
RH Myers ◽  
DA Shafer
Keyword(s):  
Parental Species ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Structural Rearrangement ◽  
Female Offspring ◽  
Nucleolus Organizer ◽  
Single Chromosome ◽  
Symphalangus Syndactylus ◽  
Hylobates Moloch ◽  
Lesser Apes

The serendipitous mating of a male gibbon, Hylobates moloch, and a female siamang, Symphalangus syndactylus, has produced two female offspring born 1 year apart. The hybrid karyotype of 47 chromosomes comprises the haploid complements of the parental species, 22 for the gibbon and 25 for the siamang. Chromosomal G and C banding comparisons revealed no clear homologies between the parental karyotypes except for the single chromosome in each species containing the nucleolus organizer region. The lack of homology suggests that the structural rearrangement of chromosomes has played a major role in the process of speciation for these lesser apes.

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