Cytogenetic Characterization of Two Metynnis Species (Characiformes, Serrasalmidae) Reveals B Chromosomes Restricted to the Females

2019 ◽  
Vol 158 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Ramon M. Favarato ◽  
Leila Braga Ribeiro ◽  
Rafaela P. Ota ◽  
Celeste M. Nakayama ◽  
Eliana Feldberg
Keyword(s):  
5S Rdna ◽  
B Chromosome ◽  
B Chromosomes ◽  
C Banding ◽  
Retrotransposable Elements ◽  
Rdna Sites ◽  
Species Pairs ◽  
Cytogenetic Characterization ◽  
Female Genome

Karyotypes and chromosomal characteristics with focus on B chromosomes of 2 species of the serrasalmid genus Metynnis, namely M. lippincottianus and M. maculatus, were examined using conventional (C-banding) and molecular (FISH mapping of minor and major rDNAs and Rex1, Rex3, and Rex6 retrotransposable elements) protocols. Both species possessed a diploid chromosome number of 2n = 62 and karyotypes composed of 32 metacentric + 28 submetacentric + 2 subtelocentric and 32 metacentric + 26 submetacentric + 4 subtelocentric, respectively; one small B element was found in the female genome of M. lippincottianus. C-banding revealed heterochromatin in the pericentromeric and terminal portions of all chromosomes of both species; the B chromosome was entirely heterochromatic. FISH showed 18S rDNA sites in 2 chromosome pairs in both species (pairs 19 and 22), and a large block in the B chromosome, while 5S rDNA signals were detected in the first pair of subtelocentric chromosomes in both species, moreover in M. maculatus an additional labeled pair 4 was observed. Mapping of the Rex1, Rex3, and Rex6 retrotransposable elements in the genomes of M. lippincottianus and M. maculatus indicated that they were dispersed throughout nearly all the chromosomes of the complement, except for the B chromosome of M. lippincottianus.

scholarly journals First cytogenetic characterization of the Amazon Catfish Leiarius marmoratus (Gill, 1870) and its hybrid with Pseudoplatystoma reticulatum (Eigenmann & Eigenmann, 1889)

Caryologia ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 127-133
Author(s):  
Fernanda Dotti do Prado ◽  
Andrea Abrigato de Freitas Mourão ◽  
Fausto Foresti ◽  
José Augusto Senhorini ◽  
Fabio Porto-Foresti
Keyword(s):  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
5S Rdna ◽  
Nucleolus Organizer ◽  
Intraindividual Variation ◽  
Nucleolar Dominance ◽  
Rdna Sites ◽  
Telocentric Chromosomes ◽  
Cytogenetic Characterization

This study reports the first cytogenetic characterization of the Amazonian catfish Leiarius marmoratus (“jandiá”) and its F1 (first generation) hybrid “cachandiá” with Pseudoplatystoma reticulatum (“cachara”). A diploid number of 56 chromosomes and a single argyrophilic nucleolus organizer region (Ag-NOR) in the short arm of two sub-telocentric chromosomes were observed for both L. marmoratus and P. reticulatum, but with differences in the karyotype formula and the size of the chromosome pair with NORs. The hybrid showed 2n = 56 chromosomes with an intermediate karyotype when compared to the parental species. A single Ag-NOR was maintained in the hybrid but located in two chromosomes with marked differences in size and presenting intraindividual variation in NOR activity (nucleolar dominance). For L. marmoratus and the hybrid, heterochromatic bands were predominately distributed in the terminal, centromeric, and sub-centromeric regions of some chromosomes and 5S rDNA sites located in two distinct sub-telocentric chromosomes, similar to the previously described for P. reticulatum. The data suggested that the hybrid karyotype might be insufficient for a precise discrimination of hybrids, however, Ag-NOR can be used as a chromosome marker to differentiate “cachandiá” from L. marmoratus and P. reticulatum. The current study also provides insights into the chromosomal features of L. marmoratus and contributes with novel cytogenetic information of this native Amazonian catfish included in the Pimelodidae family.

scholarly journals Cytogenetic characterization of Melipona rufiventris Lepeletier 1836 and Melipona mondury Smith 1863 (Hymenoptera, Apidae) by C banding and fluorochromes staining

2008 ◽  
Vol 31 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Denilce Meneses Lopes ◽  
Sílvia das Graças Pompolo ◽  
Lúcio Antônio de Oliveira Campos ◽  
Mara Garcia Tavares
Keyword(s):  
C Banding ◽  
Cytogenetic Characterization

Molecular and cytological characterization of genomic variability in hexaploid wheat 'Lindström'

Genome ◽  
2005 ◽  
Vol 48 (5) ◽  
pp. 895-904
Author(s):  
Pedro Costa-Nunes ◽  
Teresa Ribeiro ◽  
Margarida Delgado ◽  
Leonor Morais-Cecílio ◽  
Neil Jones ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Large Scale ◽  
Expression Patterns ◽  
5S Rdna ◽  
Rdna Locus ◽  
B Chromosomes ◽  
Addition Line ◽  
Rdna Loci

'Lindström' wheat (AABBDD + rye B chromosomes) was used to study the effects of alien chromatin introgressed into a wheat genetic background, subjecting the wheat genome to a new and transient allopolyploidisation episode. Using this experimental material, we have previously demonstrated that no large-scale chromosomal translocations occurred as a result of the genomic constitution of the addition line. However, we have shown that the presence of a number of rye B chromosomes is associated with changes in the interphase organization and expression patterns of wheat rDNA loci. We have now extended our studies to focus on a further characterization of 'Lindström' 5S rDNA loci and also on high molecular weight glutenin subunit (HMW-GS) patterns. In the process, we have uncovered an unusually large variant of the 5S rDNA locus on wheat chromosome 1B (not to be confused with rye B chromosomes) and 2 novel HMW glutenin y-type alleles. These changes are not directly related to variation in rye B chromosome number in the present material, but the fact that a new, and still segregating, 1Dy HMW-GS gene was identified indicates a recent timescale for its origin. Strikingly, the 'Lindström' 5S rDNA 1B locus integrates a unit sharing 94% homology with a rye 5S rDNA sequence, suggesting the possibility that the wheat locus was colonized by highly homologous rye sequences during the breeding of 'Lindström', when the rye and wheat genomes were together, albeit briefly, in the same nucleus.Key words: Triticum aestivum 'Lindström', allopolyploidisation, 5S rDNA, NTS, high molecular weight glutenin (HMW-GS).

scholarly journals Cytogenetic characterization of Aloysia virgata Ruiz and Pavan (Verbenaceae)

2009 ◽  
Vol 52 (4) ◽  
pp. 893-899
Author(s):  
Aline Dias Brandão ◽  
Lyderson Facio Viccini ◽  
Shirlei Maria Recco-Pimentel
Keyword(s):  
Interphase Nucleus ◽  
5S Rdna ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Meiotic Behavior ◽  
Meiotic Analysis ◽  
Chromosomal Pair ◽  
Cytogenetic Characterization

Since previous cytogenetic reports of Aloysia have only described the meiotic behavior and chromosomal number of some species, the aim of this work was to provide detailed cytogenetic description of Aloysia virgata that would contribute to the understanding of the taxonomical organization of the Verbenaceae. Aloysia virgata had a karyotype with 2n = 36 metacentric chromosomes, all with similar size. The large amount of heterochromatin seen after Giemsa staining was confirmed by C-banding. Four nucleolar organizer regions (NORs) were detected with an rDNA 45S probe in two homologous pairs and two sites of 5S rDNA located on one chromosomal pair were detected by fluorescence in situ hybridization. The interphase nucleus was classified as semi-reticulate. Meiotic analysis showed a normal chromosomal behavior, with 18 bivalents in some parts of prophase I and in metaphase I. The number of chromosomes, NORs and 5S rDNA segments did not exclude a possible polyploid origin.

Comparative Cytogenetics of Hoplerythrinus unitaeniatus (Agassiz, 1829) (Characiformes, Erythrinidae) Species Complex from Different Brazilian Hydrographic Basins

2016 ◽  
Vol 149 (3) ◽  
pp. 191-200 ◽  
Author(s):  
Juliana F. Martinez ◽  
Roberto L. Lui ◽  
Josiane B. Traldi ◽  
Daniel R. Blanco ◽  
Orlando Moreira-Filho
Keyword(s):  
Silver Nitrate ◽  
Species Complex ◽  
5S Rdna ◽  
River Basins ◽  
Telomeric Sequence ◽  
Comparative Cytogenetics ◽  
C Banding ◽  
Araguaia River ◽  
Rdna Sites ◽  
Hoplerythrinus Unitaeniatus

Chromosomal characteristics of Hoplerythrinus unitaeniatus populations from 5 Brazilian river basins, namely Arinos (Amazonas basin), Araguaia, Paraguai, Alto Paraná, and São Francisco were analyzed by conventional Giemsa staining, C-banding, silver nitrate impregnation, and fluorescence in situ hybridization (FISH) with 18S and 5S rDNA and telomeric sequence (TTAGGG)n probes. The diploid chromosome number was 2n = 48 in representatives of the populations from Paraguai and Alto Paraná River basins and 2n = 52 for those from the Arinos and Araguaia River basins. The São Francisco population had individuals with 2n = 50 and 52 occurring in sympatry. C-banding showed heterochromatic blocks mainly located at interstitial and pericentromeric positions in most of the chromosomes. Silver nitrate impregnation demonstrated simple NORs for representatives from Arinos and Araguaia River populations and multiple NORs for specimens from Paraguai, Alto Paraná, and São Francisco River populations. FISH with 18S and 5S rDNA probes revealed many chromosomes carrying these cistrons, with up to 21 chromosomes bearing 18S rDNA sites (Alto Rio Paraná basin) and up to 12 chromosomes with 5S rDNA sites (Paraguai basin), besides the occurrence of colocalization in all populations. FISH with telomeric sequence (TTAGGG)n detected sites in the terminal portion of the chromosomes in all populations. These data reinforce the idea that H. unitaeniatus is a species complex. Evolutionary and biogeographical aspects of the group in the Neotropical region are discussed.

scholarly journals Characterization of a Maize Chromosome 4 Centromeric Sequence: Evidence for an Evolutionary Relationship With the B Chromosome Centromere

Genetics ◽  
2001 ◽  
Vol 159 (1) ◽  
pp. 291-302 ◽  
Author(s):  
Brent T Page ◽  
Michael K Wanous ◽  
James A Birchler
Keyword(s):  
Evolutionary Relationship ◽  
Bac Library ◽  
B Chromosome ◽  
B Chromosomes ◽  
Chromosome 4 ◽  
Centromeric Sequence ◽  
Unit Repeat ◽  
Specific Sequences

Abstract Previous work has identified sequences specific to the B chromosome that are a major component of the B centromere. To address the issue of the origin of the B and the evolution of centromere-localized sequences, DNA prepared from plants without B chromosomes was probed to seek evidence for related sequences. Clones were isolated from maize line B73 without B chromosomes by screening DNA at reduced stringency with a B centromeric probe. These clones were localized to maize centromere 4 using fluorescence in situ hybridization. They showed homology to a maize centromere-mapped sequence, to maize B chromosome centromere sequences, and to a portion of the unit repeat of knobs, which act as neocentromeres in maize. A representative copy was used to screen a BAC library to obtain these sequences in a larger context. Each of the six positive BACs obtained was analyzed to determine the nature of centromere 4-specific sequences present. Fifteen subclones of one BAC were sequenced and the organization of this chromosome 4-specific repeat was examined.

Multiple supernumerary chromosomes in the pseudogamous parthenogenetic flatworm Polycelis nigra: lineage markers or remnants of genetic leakage?

Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 850-856 ◽  
Author(s):  
Timothy F. Sharbel ◽  
Leo W. Beukeboom ◽  
Laas P. Pijnacker
Keyword(s):  
Chromosome Doubling ◽  
B Chromosome ◽  
B Chromosomes ◽  
Banding Technique ◽  
Free Living ◽  
Transmission Rates ◽  
Supernumerary Chromosomes ◽  
C Banding ◽  
Male Line ◽  
Lineage Markers

Polycelis nigra is a free-living simultaneous hermaphroditic flatworm that has amphimictic and pseudogamous parthenogenetic biotypes. Sexual individuals are always diploid (2n = 16) and pseudogamous parthenogens are polyploid (usually triploid). Two types of supernumerary chromosomes are found in parthenogens, those resembling autosomes ("A-like") and typical B chromosomes, both of which reach frequencies in populations of close to 100%. Experiments measuring the transmission rates of the B chromosomes indicated that they are potentially inherited via the male line, escaping expulsion by pseudogamous parthenogenesis. This study used the C-banding technique to demonstrate (i) that there is a single morphologically distinct B chromosome (B1) and (ii) that there are two "A-like" chromosomes that can be considered B chromosomes (B2 and B3) and which are not simple polysomics of one of the eight autosomes. As there is no genetic exchange between pseudogamous parthenogenetic lineages, two different individuals carrying a similar B morph must either have received it through common ancestry (a lineage marker) or have acquired it horizontally from another parthenogenetic lineage (leakage). C-banding further revealed intra-individual heteromorphy for band regions on chromosomes 5 and 8. This supports the karyotypic observation that oogenesis is preceded by premeiotic chromosome doubling followed by pairing of replicate homologues.Key words: B chromosome, C-banding, heterochromatin, heteromorphy, pseudogamous parthenogenesis.

Chromosomal Mapping of Repeat DNA in Bergiaria westermanni (Pimelodidae, Siluriformes): Localization of 45S rDNA in B Chromosomes

2018 ◽  
Vol 154 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Geovana C. Malimpensa ◽  
Josiane B. Traldi ◽  
Danyelle Toyama ◽  
Flávio Henrique-Silva ◽  
Marcelo R. Vicari ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Indirect Evidence ◽  
5S Rdna ◽  
B Chromosomes ◽  
Chromosomal Mapping ◽  
Interindividual Variation ◽  
Rrna Genes ◽  
45S Rdna ◽  
Rdna Sites ◽  
Repeat Dna

The occurrence of repetitive DNA in autosomes and B chromosomes of Bergiaria westermanni was examined using conventional and molecular cytogenetic techniques. This species exhibited 2n = 56 chromosomes, with intra- and interindividual variation in the number of heterochromatic B chromosomes (from 0 to 4). The 5S rDNA was localized in pairs 1 and 5, and histone probes (H1, H3, and H4) and U2 small nuclear RNA were syntenic with 5S rDNA in pair 5. Histone sequences were also located in chromosome pair 14. The (GATA)n sequence was dispersed throughout the autosomes and B chromosomes, with clusters (microsatellite accumulation) in some chromosome regions. The telomeric probe revealed no signs of chromosomal rearrangements in the genome of B. westermanni. The 45S rDNA sites were detected in the terminal region of pair 27; these sites corresponded to a GC-rich heterochromatin block. In addition, 3 of the 4 B chromosomes also contained 45S rDNA copies. Silver nitrate staining in interphase nuclei provided indirect evidence of the expression of these rRNA genes in B chromosomes, indicating the probable origin of these elements. This report shows plasticity in the chromosomal localization of repeat DNA in B. westermanni and features a discussion of genomic diversification.

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