scholarly journals rDNA mapping, heterochromatin characterization and AT/GC content of Agapanthus africanus (L.) Hoffmanns (Agapanthaceae)

2016 ◽  
Vol 88 (3 suppl) ◽  
pp. 1727-1734
Author(s):  
ARYANE C. REIS ◽  
ANA LUIZA FRANCO ◽  
VICTÓRIA R. CAMPOS ◽  
FLÁVIA R. SOUZA ◽  
CRISTIANE ZORZATTO ◽  
...  
Keyword(s):  
Dna Content ◽  
Gc Content ◽  
5S Rdna ◽  
Chromosome 9 ◽  
Rdna Sites ◽  
Rdna Signal ◽  
Plant Taxon ◽  
2C Dna Content

ABSTRACT Agapanthus (Agapanthaceae) has 10 species described. However, most taxonomists differ respect to this number because the great phenotypic plasticity of the species. The cytogenetic has been an important tool to aid the plant taxon identification, and to date, all taxa of Agapanthus L'Héritier studied cytologically, presented 2n = 30. Although the species possess large chromosomes, the group is karyologically little explored. This work aimed to increase the cytogenetic knowledge of Agapanthus africanus (L.) Hoffmanns by utilization of chromosome banding techniques with DAPI / CMA3 and Fluorescent in situ Hybridization (FISH). In addition, flow cytometry was used for determination of DNA content and the percentage of AT / GC nitrogenous bases. Plants studied showed 2n = 30 chromosomes, ranging from 4.34 - 8.55 µm, with the karyotype formulae (KF) = 10m + 5sm. Through FISH, one 45S rDNA signal was observed proximally to centromere of the chromosome 7, while for 5S rDNA sites we observed one signal proximally to centromere of chromosome 9. The 2C DNA content estimated for the species was 2C = 24.4 with 59% of AT and 41% of GC. Our data allowed important upgrade for biology and cytotaxonomy of Agapanthus africanus (L.) Hoffmanns.

Determination of nuclear DNA content in fungi using mithramycin: vegetative diploidy in Armillaria mellea confirmed

1983 ◽  
Vol 29 (9) ◽  
pp. 1179-1183 ◽  
Author(s):  
A. L. Franklin ◽  
W. G. Filion ◽  
J. B. Anderson
Keyword(s):  
Dna Binding ◽  
Aspergillus Nidulans ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Phytopathogenic Fungus ◽  
Armillaria Mellea ◽  
Dna Measurements

Armillaria mellea, a phytopathogenic fungus, is the only member of the Agaricales (Basidiomycetes) whose fertile vegetative phase in nature is thought to be diploid, rather than dikaryotic. To examine the vegetative ploidy of A. mellea, we used the DNA-binding antibiotic, mithramycin, for fluorometry of in situ nuclear DNA. The measurements of nuclear DNA content indicated that strains derived from single basidiospores of A. mellea were haploid and that strains derived from matings of isolates of single spores were diploid. These data confirm the results of earlier genetic experiments, which show haploidy and diploidy in unmated and mated strains, respectively. Nuclear DNA measurements in known haploid and diploid strains of Aspergillus nidulans confirmed the validity of our protocol.

Comparative cytogenetic analysis of Avena macrostachya and diploid C-genome Avena species

Genome ◽  
2010 ◽  
Vol 53 (2) ◽  
pp. 125-137 ◽  
Author(s):  
Ekaterina D. Badaeva ◽  
Olga Yu. Shelukhina ◽  
Axel Diederichsen ◽  
Igor G. Loskutov ◽  
Vitaly A. Pukhalskiy
Keyword(s):  
5S Rdna ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Rrna Gene ◽  
Avena Species ◽  
Rdna Sites ◽  
C Genome ◽  
Genome Group ◽  
26S Rrna

The chromosome set of Avena macrostachya Balansa ex Coss. et Durieu was analyzed using C-banding and fluorescence in situ hybridization with 5S and 18S-5.8S-26S rRNA gene probes, and the results were compared with the C-genome diploid Avena L. species. The location of major nucleolar organizer regions and 5S rDNA sites on different chromosomes confirmed the affiliation of A. macrostachya with the C-genome group. However, the symmetric karyotype, the absence of “diffuse heterochromatin”, and the location of large C-band complexes in proximal chromosome regions pointed to an isolated position of A. macrostachya from other Avena species. Based on the distribution of rDNA loci on the C-genome chromosomes of diploid and polyploid Avena species, we propose a model of the chromosome alterations that occurred during the evolution of oat species.

Karyotype analysis of Lilium longiflorum and Lilium rubellum by chromosome banding and fluorescence in situ hybridisation

Genome ◽  
2001 ◽  
Vol 44 (5) ◽  
pp. 911-918 ◽  
Author(s):  
Ki-Byung Lim ◽  
Jannie Wennekes ◽  
J Hans de Jong ◽  
Evert Jacobsen ◽  
Jaap M van Tuyl
Keyword(s):  
In Situ Hybridisation ◽  
5S Rdna ◽  
Lilium Longiflorum ◽  
Fluorescence In Situ Hybridisation ◽  
45S Rdna ◽  
C Banding ◽  
Rdna Sequences ◽  
Rdna Signal ◽  
5S And 45S Rdna

Detailed karyotypes of Lilium longiflorum and L. rubellum were constructed on the basis of chromosome arm lengths, C-banding, AgNO3 staining, and PI-DAPI banding, together with fluorescence in situ hybridisation (FISH) with the 5S and 45S rDNA sequences as probes. The C-banding patterns that were obtained with the standard BSG technique revealed only few minor bands on heterologous positions of the L. longiflorum and L. rubellum chromosomes. FISH of the 5S and 45S rDNA probes on L. longiflorum metaphase complements showed overlapping signals at proximal positions of the short arms of chromosomes 4 and 7, a single 5S rDNA signal on the secondary constriction of chromosome 3, and one 45S rDNA signal adjacent to the 5S rDNA signal on the subdistal part of the long arm of chromosome 3. In L. rubellum, we observed co-localisation of the 5S and 45S rDNA sequences on the short arm of chromosomes 2 and 4 and on the long arms of chromosomes 2 and 3, and two adjacent bands on chromosome 12. Silver staining (Ag-NOR) of the nucleoli and NORs in L. longiflorum and L. rubellum yielded a highly variable number of signals in interphase nuclei and only a few faint silver deposits on the NORs of mitotic metaphase chromosomes. In preparations stained with PI and DAPI, we observed both red- and blue-fluorescing bands at different positions on the L. longiflorum and L. rubellum chromosomes. The red-fluorescing or so-called reverse PI-DAPI bands always coincided with rDNA sites, whereas the blue-fluorescing DAPI bands corresponded to C-bands. Based on these techniques, we could identify most of chromosomes of the L. longiflorum and L. rubellum karyotypes.Key words: fluorescence in situ hybridisation, FISH, 5S rDNA, 45S rDNA, C-banding, reverse PI-DAPI banding.

Comparative chromosomal localization of 45S and 5S rDNAs and implications for genome evolution in Cucumis

Genome ◽  
2016 ◽  
Vol 59 (7) ◽  
pp. 449-457 ◽  
Author(s):  
Zhen-Tao Zhang ◽  
Shu-Qiong Yang ◽  
Zi-Ang Li ◽  
Yun-Xia Zhang ◽  
Yun-Zhu Wang ◽  
...  
Keyword(s):  
Chromosomal Localization ◽  
5S Rdna ◽  
Chromosome Analysis ◽  
45S Rdna ◽  
Evolutionary Patterns ◽  
Site Number ◽  
Rdna Sites ◽  
Wild Accessions ◽  
Ribosomal Dnas

Ribosomal DNAs are useful cytogenetic markers for chromosome analysis. Studies investigating site numbers and distributions of rDNAs have provided important information for elucidating genome organization and chromosomal relationships of many species by fluorescence in situ hybridization. But relevant studies are scarce for species of the genus Cucumis, especially in wild species. In the present study, FISH was conducted to investigate the organization of 45S and 5S rDNA among 20 Cucumis accessions, including cultivars and wild accessions. Our results showed that the number of 45S rDNA sites varied from one to five pairs in different accessions, and most of these sites are located at the terminal regions of chromosomes. Interestingly, up to five pairs of 45S rDNA sites were observed in C. sativus var. sativus, the species which has the lowest chromosome number, i.e., 2n = 14. Only one pair of 5S rDNA sites was detected in all accessions, except for C. heptadactylus, C. sp, and C. spp that had two pairs of 5S rDNA sites. The distributions of 5S rDNA sites showed more variation than 45S rDNA sites. The phylogenetic analysis in this study showed that 45S and 5S rDNA have contrasting evolutionary patterns. We find that 5S rDNA has a polyploidization-related tendency towards the terminal location from an interstitial location but maintains a conserved site number, whereas the 45S rDNA showed a trend of increasing site number but a relatively conserved location.

Heterochromatin patterns and ribosomal DNA loci distribution in diploid and polyploid Crotalaria species (Leguminosae, Papilionoideae), and inferences on karyotype evolution

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 718-726 ◽  
Author(s):  
Mateus Mondin ◽  
Margarida L.R. Aguiar-Perecin
Keyword(s):  
Dna Sequence ◽  
Ribosomal Dna ◽  
Karyotype Evolution ◽  
5S Rdna ◽  
Rdna Locus ◽  
Variable Number ◽  
Chromosome 1 ◽  
Distamycin A ◽  
Rdna Sites

Most Crotalaria species display a symmetric karyotype with 2n = 16, but 2n = 14 is found in Chrysocalycinae subsection Incanae and 2n = 32 in American species of the section Calycinae. Seven species of the sections Chrysocalycinae, Calycinae, and Crotalaria were analyzed for the identification of heterochromatin types with GC- and AT-specific fluorochromes and chromosomal location of ribosomal DNA loci using fluorescent in situ hybridization (FISH). A major 45S rDNA locus was observed on chromosome 1 in all the species, and a variable number of minor ones were revealed. Only one 5S rDNA locus was observed in the species investigated. Chromomycin A3 (CMA) revealed CMA+ bands colocalized with most rDNA loci, small bands unrelated to ribosomal DNA on two chromosome pairs in Crotalaria incana, and CMA+ centromeric bands that were quenched by distamycin A were detected in species of Calycinae and Crotalaria sections. DAPI+ bands were detected in C. incana. The results support the species relationships based on flower specialization and were useful for providing insight into mechanisms of karyotype evolution. The heterochromatin types revealed by fluorochromes suggest the occurrence of rearrangements in repetitive DNA families in these heterochromatic blocks during species diversification. This DNA sequence turnover and the variability in number/position of rDNA sites could be interpreted as resulting from unequal crossing over and (or) transposition events. The occurrence of only one 5S rDNA locus and the smaller chromosome size in the polyploids suggest that DNA sequence losses took place following polyploidization events.

Chromatin characterization by banding techniques, in situ hybridization, and nuclear DNA content in Cicer L. (Leguminosae)

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 258-265 ◽  
Author(s):  
I. Galasso ◽  
D. Pignone ◽  
M. Frediani ◽  
M. Maggiani ◽  
R. Cremonini
Keyword(s):  
In Situ Hybridization ◽  
Dna Content ◽  
Nuclear Dna ◽  
Hybrid Sterility ◽  
Nuclear Dna Content ◽  
5S Rdna ◽  
Rrna Genes ◽  
Evolutionary Pathway ◽  
C Banding

The karyotypes of three accessions, one each from three annual species of the genus Cicer, namely Cicer arietinum, Cicer reticulation, and Cicer echinospermum, were examined and compared using C-banding, the fluorochromes chromomycin A3, DAPI, and Hoechst 33258, in situ hybridization of the 18S–5.8S–25S and 5S rDNA sequences, and silver staining. The nuclear DNA content of the three species and the amount of heterochromatin were also determined. The results suggest an evolutionary pathway in which C. reticulatum is the ancestral species from which both C. arietinum and C. echinospermum are derived with the loss of one pair of satellites; subsequently, C. echinospermum further differentiated by the accumulation of chromosomal rearrangement(s) that gave rise to a hybrid sterility barrier. Key words : Cicer, C-banding, fluorochromes, Ag staining, rRNA genes.

Evolutionary Dynamics of 5S rDNA and Recurrent Association of Transposable Elements in Electric Fish of the Family Gymnotidae (Gymnotiformes): The Case of Gymnotus mamiraua

2016 ◽  
Vol 149 (4) ◽  
pp. 297-303 ◽  
Author(s):  
Maelin da Silva ◽  
Patricia Barbosa ◽  
Roberto F. Artoni ◽  
Eliana Feldberg
Keyword(s):  
Electric Fish ◽  
Evolutionary Dynamics ◽  
Chromosomal Location ◽  
Molecular Mapping ◽  
5S Rdna ◽  
Mapping Data ◽  
Rdna Sequences ◽  
Rdna Sites ◽  
The Family

Gymnotidae is a family of electric fish endemic to the Neotropics consisting of 2 genera: Electrophorus and Gymnotus. The genus Gymnotus is widely distributed and is found in all of the major Brazilian river systems. Physical and molecular mapping data for the ribosomal DNA (rDNA) in this genus are still scarce, with its chromosomal location known in only 11 species. As other species of Gymnotus with 2n = 54 chromosomes from the Paraná-Paraguay basin, G. mamiraua was found to have a large number of 5S rDNA sites. Isolation and cloning of the 5S rDNA sequences from G. mamiraua identified a fragment of a transposable element similar to the Tc1/mariner transposon associated with a non-transcribed spacer. Double fluorescence in situ hybridization analysis of this element and the 5S rDNA showed that they were colocalized on several chromosomes, in addition to acting as nonsyntenic markers on others. Our data show the association between these sequences and suggest that the Tc1 retrotransposon may be the agent that drives the spread of these 5S rDNA-like sequences in the G. mamiraua genome.

Determination of basic chromosome numbers in the genus Saccharum by physical mapping of ribosomal RNA genes

Genome ◽  
1998 ◽  
Vol 41 (2) ◽  
pp. 221-225 ◽  
Author(s):  
Angélique D'Hont ◽  
David Ison ◽  
Karine Alix ◽  
Catherine Roux ◽  
Jean Christophe Glaszmann
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Numbers ◽  
Saccharum Officinarum ◽  
Basic Chromosome Number ◽  
Genetic Maps ◽  
Basic Chromosome ◽  
Rdna Sites ◽  
Rna Genes

18S-5.6S-25S and 5S ribosomal DNA (rDNA) sites were located by in situ hybridization to the three main species of the Saccharum genus. For each species and each rDNA family, the position and number of sites in the various cytotypes suggested the presence of one locus and basic chromosome numbers of 10 for Saccharum officinarum and Saccharum robustum and\i 8 forSaccharum spontaneum. The implications of these results for the genetic maps of modern cultivars derived from crosses between the species S. officinarum and S. spontaneum are discussed.Key words: sugarcane, Saccharum, 18S-5.6S-25S rRNA, 5S rRNA, basic chromosome number, in situ hybridization.

Genome multiplication is a generalised phenomenon in placentomal and interplacentomal trophoblast giant cells in cattle

2004 ◽  
Vol 16 (3) ◽  
pp. 301 ◽  
Author(s):  
Karl Klisch ◽  
Preben D. Thomsen ◽  
Vibeke Dantzer ◽  
Rudolf Leiser
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
In Situ Hybridisation ◽  
Nuclear Dna Content ◽  
Giant Cells ◽  
Crown Rump Length ◽  
Subsequent Determination ◽  
Trophoblast Giant Cells

The frequency of polyploidisation in bovine binucleate trophoblast giant cells (TGC) from placentomes (PL) and the interplacentomal allantochorion (AL) of six male fetuses with a crown–rump length between 3.5 and 103 cm was determined by in situ hybridisation with a chromosome-7-specific probe, using a probe specific for the Y chromosome to distinguish between maternal and fetal nuclei. The results showed that polyploid nuclei were essentially always of fetal origin. The frequency of tetraploid nuclei varied between 3% and 15% in both the placentomal and interplacentomal samples, with mean frequencies of 8.8% and 10.0% respectively. Octoploid nuclei were observed with a mean frequency of 1.1% in the interplacentomal samples, but were absent in samples from placentomes. Subsequent determination of nuclear DNA content by cytophotometric measurement of Feulgen-stained nuclei revealed that the frequency of nuclei with an 8C DNA content was several fold higher (AL 5.4%; PL 7.8%) than the frequency of octoploidy, suggesting that tetraploid TGC cells are arrested in the G2 phase of the cell cycle.

Comparative analysis of rDNA distribution in 29 species of Begonia sect. Coelocentrum Irmsch.

Phytotaxa ◽  
2018 ◽  
Vol 381 (1) ◽  
pp. 141 ◽  
Author(s):  
YAN-LI HAN ◽  
DAI-KE TIAN ◽  
NAI-FENG FU ◽  
YAN XIAO ◽  
ZONG-YUN LI ◽  
...  
Keyword(s):  
5S Rdna ◽  
Distribution Patterns ◽  
Hybrid Origin ◽  
45S Rdna ◽  
Species Relationships ◽  
Rdna Sites ◽  
Rdna Fish ◽  
5S And 45S Rdna ◽  
Chromosome Landmarks

The rDNA sites are useful chromosome landmarks and can provide valuable information for species identification and species relationships. In this study, we investigated the distribution of 5S and 45S rDNA sites in 29 species of Begonia sect. Coelocentrum Irmsch. using a two-colour fluorescence in situ hybridization (FISH) technique. This is the first report of chromosomal rDNA mapping in Begonia species. The analyzed species showed considerable diversity in rDNA distribution patterns. The 45S rDNA signals are always located in terminal regions on 1−4 chromosomes, while 5S rDNA signals are mainly located at proximal regions on 2−8 chromosomes, varying from specific major signals to highly dispersed minor signals. Based on rDNA FISH patterns, most of the investigated species could be distinguished from each other and species relationships were identified. In addition, the results provided clear proof that B. huangii is of hybrid origin and the triploid B. longgangensis was allotriploid rather than autotriploid as suggested before. The data will provide a useful reference for evaluation, conservation and utilization of the natural resources of the mega-diverse genus Begonia.

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