Cytological studies of the nucleolus organizing regions in the Medicago complex: sativa–coerulea–falcata

Genome ◽  
1996 ◽  
Vol 39 (5) ◽  
pp. 914-920 ◽  
Author(s):  
O. Calderini ◽  
F. Pupilli ◽  
P. D. Cluster ◽  
A. Mariani ◽  
S. Arcioni
Keyword(s):  
In Situ Hybridization ◽  
Silver Nitrate ◽  
Fluorescent In Situ Hybridization ◽  
Diploid Species ◽  
2N Gametes ◽  
Root Tip ◽  
Medicago Falcata ◽  
Rdna Sites ◽  
Silver Nitrate Staining

A cytological examination of the nucleolus organizing regions (NORs) of three species from the Medicago sativa complex was conducted to evaluate the structural and functional evolution of the ribosomal RNA (rRNA) loci that encode the 18S, 5.8S, and 26S rRNAs. Mitotic chromosomes in root-tip preparations from tetraploid M. sativa and diploids Medicago coerulea and Medicago falcata were visualized by four methods that provide new data. Fluorescent in situ hybridization using the M. sativa 18S gene as probe localized the structural rDNA to the constricted regions of the satellited chromosomes only. Chromomycin A3 (CMA3) staining and 4′,6-diamidino-2-phenylindole (DAPI) staining identified these chromosomal segments as the most GC-rich regions in the alfalfa karyotype. Medicago falcata exhibited fewer DAPI bands and chromocenters than did M. sativa and M. coerulea. Positive silver nitrate staining showed that all four rDNA regions in M. sativa (located in two chromosome pairs) and both rDNA sites in both diploid species remain transcriptionally active. Counts of nucleoli confirmed that all rDNA regions are independently capable of nucleolus organization. Thus, the number of active NORs in M. sativa is double the number found in M. coerulea or M. falcata. Consequently, if M. sativa originated from sexual hybridization of 2n gametes involving one or both diploid species, no major reorganization or loss of structural or functional rDNA loci has occurred. Key words : alfalfa evolution, CMA3 banding, DAPI banding, fluorescent in situ hybridization, silver nitrate staining.

scholarly journals Comparative molecular cytogenetics in Melipona Illiger species (Hymenoptera, Apidae)

Sociobiology ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 696 ◽  
Author(s):  
Vanderly Andrade-Souza ◽  
Olivia Maria Pereira Duarte ◽  
Cinthia Caroline Cardoso Martins ◽  
Igor Silva Santos ◽  
Márcio Gilberto Cardoso Costa ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Number ◽  
Fluorescent In Situ Hybridization ◽  
Molecular Cytogenetics ◽  
Fluorochrome Staining ◽  
Rdna Sites ◽  
Cytogenetic Studies ◽  
Melipona Species ◽  
Almost All

Cytogenetic studies in Melipona are scarce with only 24 species analyzed cytogenetically. Of these, six species had the rDNA sites physically mapped and characterized by Fluorescent in situ Hybridization (fish). The aim of this study was to perform karyotype analyzes on Melipona species from different regions of Brazil, with a greater sampling representative of the Amazonian fauna and using conventional, fluorochrome staining and FISH with heterologous rDNA probes. The predominant chromosome number was 2n = 18, however, the subspecies M. seminigra abunensis and M. s. pernigra showed 2n = 22 chromosomes. The karyotypes were symmetrical, however M. bicolor, M. quadrifasciata, M. flavolineata, M. fuscopilosa, M. nebulosa presented the first pair heteromorphic in length. CMA3+ blocks also exhibited heteromorphism of size and in almost all cases coincided with rDNA sites, except for M. crinita and M. nebulosa, which presented additional non-coincident CMA3+ blocks. The CMA/ rDNA sites were terminal and interstitial in species with high heterochromatic content, and pericentromeric in those species with low heterochromatic content. In addition to pointing out cytogenetic features of cytotaxonomic importance, the reorganization of the genome in Melipona is discussed.

scholarly journals Monocentric chromosomes in Juncus (Juncaceae) and implications for the chromosome evolution of the family

2019 ◽  
Vol 191 (4) ◽  
pp. 475-483 ◽  
Author(s):  
Marcelo Guerra ◽  
Tiago Ribeiro ◽  
Leonardo P Felix
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Chromosome Evolution ◽  
Holocentric Chromosomes ◽  
Mitotic Chromosomes ◽  
Restricted Area ◽  
Rdna Sites ◽  
The Family ◽  
Meiotic Analyses

Abstract Holocentric chromosomes are rare among angiosperms, but have been suggested to be shared by all or most of the species of Cyperaceae and Juncaceae. However, no clear demonstration of the centromere type in Juncus, the largest genus of Juncaceae, has so far been published. Thus, we conducted a detailed chromosomal investigation of four Juncus spp. aiming to identify their centromere type. Mitotic chromosomes were analysed using the fluorochromes CMA and DAPI, fluorescent in situ hybridization (FISH) with rDNA probes and immunodetection of histones H3 phosphorylated at serine 10 (H3-S10ph) and H2A phosphorylated at threonine 133 (H2A-T133ph). DAPI-stained chromosomes of all species displayed typical primary constrictions, which were not related to AT-poor CMA+ heterochromatin or rDNA sites (usually negatively stained with DAPI). Immunodetection with H3-S10ph and H2A-T133ph revealed hyperphosphorylation of pericentromeric and centromeric regions, respectively, in a restricted area, as observed in monocentric chromosomes. Meiotic analyses in J. microcephalus showed no indication of inverted meiosis, commonly found in plants with holocentric chromosomes. Since the species investigated here belong to four different sections of Juncus and all of them display typical monocentric chromosomes, it seems that this kind of centromere is common in the genus and may represent the standard centromere organization for Juncus. If Juncus has monocentric chromosomes, there is no reason to hypothesize that other genera of Juncaceae for which centromeres have not been carefully investigated have holocentric chromosomes.

Genomic affinities in Turnera (subseries Turnera, Turneraceae) inferred by in situ hybridization techniques

Genome ◽  
2010 ◽  
Vol 53 (8) ◽  
pp. 594-598 ◽  
Author(s):  
Alicia López ◽  
Aveliano Fernández ◽  
Lidia Poggio
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Secondary Constriction ◽  
Meiotic Pairing ◽  
Ploidy Levels ◽  
Rdna Sites ◽  
Strong Hybridization ◽  
Strong Hybridization Signal ◽  
Molecular Affinity

Subseries Turnera comprises a polyploid complex with ploidy levels ranging from diploid (2n = 2x = 10) to octoploid (2n = 8x = 40). The use of fluorescent in situ hybridization greatly improved the knowledge of the karyotypes of Turnera species by detecting and mapping rDNA sites. Interspecific variability in the number of sites was detected, but not in correlation with the ploidy level. A chromosome pair with a strong hybridization signal was always visible and this signal corresponded to the secondary constriction detectable by conventional techniques. Genomic in situ hybridization experiments combined with information on meiotic pairing in species and interspecific hybrids revealed that homologies detected by molecular analysis are greater than those detected by chromosome pairing. This suggests that the formation of the allopolyploids could involve species more closely related than previously assumed. Despite the molecular affinity among the genomes, the meiotic pairing is probably controlled by specific genes that restrict homeologous pairing in polyploids.

Homoeologous recombination in 2n-gametes producing interspecific hybrids of Lilium (Liliaceae) studied by genomic in situ hybridization (GISH)

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 681-686 ◽  
Author(s):  
G I Karlov ◽  
L I Khrustaleva ◽  
K B Lim ◽  
J M van Tuyl
Keyword(s):  
In Situ Hybridization ◽  
Interspecific Hybridization ◽  
2N Gametes ◽  
Lilium Longiflorum ◽  
Genomic In Situ Hybridization ◽  
2N Pollen ◽  
Rdna Sites ◽  
Clear Differentiation ◽  
Pollen Formation

Interspecific hybridization of Lilium longiflorum (L) with Asiatic (A) lily hybrids results in so-called LA-hybrids. Some of these hybrids produce 2n-pollen, which were used to perform crosses on Asiatic and Oriental (O) hybrids, resulting in ALA- and OLA-hybrids. Recombination between homoeologous chromosomes (introgression) and the mechanism of 2n-pollen formation in these hybrids were studied using genomic in situ hybridization (GISH). A clear differentiation between the chromosomes of L. longiflorum, Asiatic, and Oriental hybrids was observed in four ALA- and one OLA-hybrid using GISH. Two ALA-hybrids showed 3 and 5 recombinant chromosomes with a total of 5 and 10 crossover sites per hybrid, respectively. These occurred at random positions on the chromosomes. The number and the location of the rDNA-sites were determined using in situ hybridization and provided a tool, the FISH-marker, for identifying the NOR-bearing chromosomes in the lily hybrids. Evidence for the occurrence of the FDR-mechanism (first division restitution) of 2n-pollen formation in the LA-hybrids was obtained on the basis of absence of homologous chromosomes of L. longiflorum in the ALA- and OLA-hybrids.Key words: Lilium longiflorum, introgression, FDR, interspecific hybridization, FISH.

Cyto-evolution of Boronia genomes revealed by fluorescent in situ hybridization with rDNA probes

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 507-513 ◽  
Author(s):  
Fucheng Shan ◽  
Guijun Yan ◽  
Julie A Plummer
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Diploid Species ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
26S Rdna ◽  
Rdna Sequences ◽  
Gene Copies ◽  
Rdna Sites ◽  
Rdna Copy

The physical location of the 25S–26S rDNA sequences was examined in 11 taxa of nine species of Boronia. In diploid species, two rDNA sites were detected in Boronia clavata (2n = 14), Boronia pinnata 'White' (2n = 22), and Boronia chartacea (2n = 32); four in Boronia megastigma (2n = 14) and Boronia denticulata (2n = 18); six in Boronia pinnata 'Pink' (2n = 22); and eight in Boronia molloyae (2n = 16). Eleven sites were found in Boronia heterophylla 'Red' and 'Near White' (2n = 15), but only two active nucleolar organizer regions (NORs) were observed. In polyploid species, Boronia pilosa (2n = 44) had four rDNA sites, while Boronia coerulescens (2n = 72) had six. Most of the rDNA sequences were terminal, but a few were interstitial. There were also differences in signal intensity indicating that the gene copies between and within rDNA sites might be different. The result suggests that considerable chromosome rearrangements have occurred during Boronia cyto-evolution, leading to variation among Boronia taxa in rDNA copy number, site number, and location. These changes together with dysploid reduction during cyto-evolution have made the Boronia genome considerably diverse in chromosome number, genome organization, and chromosome structure.Key words: physical mapping, FISH, chromosome, Rutaceae.

Localization of 45S and 5S rDNA sites and karyotype of Chrysanthemum and its related genera by fluorescent in situ hybridization

2015 ◽  
Vol 62 ◽  
pp. 164-172 ◽  
Author(s):  
Xiangyu Qi ◽  
Fei Zhang ◽  
Zhiyong Guan ◽  
Haibin Wang ◽  
Jiafu Jiang ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
5S Rdna ◽  
Rdna Sites

scholarly journals Simultaneous Visualization of 5S and 45S rDNAs in Persimmon (Diospyros kaki) and Several Wild Relatives (Diospyros spp.) by Fluorescent in situ Hybridization (FISH) and MultiColor FISH (MCFISH)

2003 ◽  
Vol 128 (5) ◽  
pp. 736-740 ◽  
Author(s):  
Young A Choi ◽  
Ryutaro Tao ◽  
Keizo Yonemori ◽  
Akira Sugiura
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Diploid Species ◽  
5S Rdna ◽  
Diospyros Kaki ◽  
45S Rdna ◽  
Multicolor Fish ◽  
Rdna Probe ◽  
Rdna Sites ◽  
5S And 45S Rdna

5S ribosomal DNA (rDNA) was visualized on the somatic metaphase chromosome of persimmon (Diospyros kaki) and ten wild Diospyros species by fluorescent in situ hybridization (FISH). The digoxigenin (DIG)-labeled 5S rDNA probe was hybridized onto the chromosomes and visualized by incubation with anti-DIG-fluorescein isothiocyanate (FITC). Strong signals of 5S rDNA probe were observed on several chromosomes of Diospyros species tested. Furthermore, multicolor FISH using 5S and 45S rDNA probes differently labeled with DIG and biotin, revealed separate localization of the two rDNA genes on different chromosomes of Diospyros species tested, suggesting that 5S and 45S rDNA sites can be used as chromosome markers in Diospyros. The number of 5S rDNA sites varied with the Diospyros species. More 5S rDNA sites were observed in four diploid species native to Southern Africa than in three Asian diploid species. The former had four or six 5S rDNA sites while the latter had two. Three Asian polyploidy species had four to eight 5S rDNA sites. Among the Asian species, the number of 5S rDNA sites seemed to increase according to ploidy level of species. These features of 5S rDNA sites were very similar to those of 45S rDNA sites in Diospyros. Phylogenetic relationship between D. kaki and wild species tested are discussed based on the number and chromosomal distribution of 5S and 45S rDNA.

Nucleolar dominance does not occur in root tip cells of allotetraploid Brassica species

Genome ◽  
2000 ◽  
Vol 43 (3) ◽  
pp. 574-579 ◽  
Author(s):  
Robert Hasterok ◽  
Jolanta Maluszynska
Keyword(s):  
In Situ Hybridization ◽  
Nucleolar Organizer ◽  
Brassica Species ◽  
Root Tip ◽  
Nucleolar Organizer Regions ◽  
Nucleolar Dominance ◽  
Rdna Sites ◽  
Rdna Loci ◽  
Allotetraploid Species

Using in situ hybridization and silver staining methods, the numbers of active and inactive rDNA loci have been established for three allotetraploid species of Brassica (B. napus, B. carinata, and B. juncea) and their diploid ancestors (B. campestris, B. nigra, and B. oleracea). The allotetraploid species have chromosome numbers equal to the sum of the numbers in their diploid relatives, but have fewer rDNA loci. All species investigated have lower numbers of active NORs (AgNORs, nucleolar organizer regions) compared with the numbers of rDNA sites revealed by in situ hybridization. The number of active rDNA loci of the allotetraploid species is equal to the number of AgNORs in their diploid ancestors, indicating the absence of nucleolar dominance in amphidiploid Brassica species, at least in root meristematic cells.Key words: AgNOR, Brassica, FISH, nucleolar dominance, rDNA.

scholarly journals Amplification of a GC-rich heterochromatin in the freshwater fish Leporinus desmotes (Characiformes, Anostomidae)

2000 ◽  
Vol 23 (3) ◽  
pp. 569-573 ◽  
Author(s):  
Vladimir Pavan Margarido ◽  
Pedro Manoel Galetti Junior
Keyword(s):  
In Situ Hybridization ◽  
Silver Nitrate ◽  
Fluorescence In Situ Hybridization ◽  
Freshwater Fish ◽  
Telomeric Region ◽  
Nucleolar Organizing Regions ◽  
Diploid Female ◽  
Silver Nitrate Staining ◽  
Telomeric Heterochromatin

This is the first description of the karyotype of Leporinus desmotes. The diploid female number was 2n = 54 meta- and submetacentric chromosomes. The nucleolar organizing regions (NORs) were studied by silver nitrate staining and rDNA fluorescence in situ hybridization (FISH) and were found to be located in the telomeric region of the long arm of the 9th pair. C-banding revealed centromeric and telomeric heterochromatin segments in most chromosomes. Intercalar blocks of heterochromatin were observed in the long arm of six chromosome pairs. Besides a NOR-adjacent heterochromatin, all of the intercalar heterochromatic segments were brightly fluorescent by mithramycin staining. These data suggest that a unique amplification of a primordial GC-rich heterochromatin, probably NOR-associated, may have taken place in the karyotype diversification of this Leporinus species.

Cytogenetic analysis of Anaecypris hispanica and its relationship with the paternal ancestor of the diploid-polyploid Squalius alburnoides complex

Genome ◽  
2006 ◽  
Vol 49 (12) ◽  
pp. 1621-1628 ◽  
Author(s):  
Marta Gromicho ◽  
Maria Manuela Coelho ◽  
Maria Judite Alves ◽  
Maria João Collares-Pereira
Keyword(s):  
In Situ Hybridization ◽  
Cytogenetic Analysis ◽  
Fluorescent In Situ Hybridization ◽  
Nuclear Genome ◽  
5S Rdna ◽  
Genomic Rearrangements ◽  
Endangered Fish ◽  
Hybrid Complex ◽  
Rdna Sites

The karyotype of the endangered fish Anaecypris hispanica was revisited using advanced cytogenetic techniques to elucidate its putative relationship with the paternal ancestor of the hybrid complex Squalius alburnoides and to clarify some of the recently described cytogenetic patterns of the complex. The results of chromomycin A3 and Ag staining, as well as fluorescent in situ hybridization with 28S and 5S rDNA and the (TTAGGG)n telomeric probes, were compared with the patterns observed in specimens of the all-male nonhybrid lineage of S. alburnoides complex, which is considered to reconstitute the nuclear genome of the probably extinct paternal ancestor. Several cytogenetic features observed in A. hispanica specimens were indeed shared by S. alburnoides nuclear nonhybrid males, supporting the hypothesis of a close evolutionary link between A. hispanica and the paternal ancestor of the complex. The genomic rearrangements involving 28S rDNA sites previously described in the S. alburnoides complex and in its maternal ancestor ( S. pyrenaicus ) were not detected in A. hispanica; they are, therefore, probably due to mechanisms related to hybridization and polyploidy.

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