Interindividual size heteromorphism of NOR and chromosomal location of 5S rRNA genes in Iheringichthys labrosus

Carvalho, Reginaldo de; Dias, Ana Lúcia

doi:10.1590/s1516-89132007000100017

Cited by 11 publications

(11 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2c) as also observed in some Pimelodidae species by different authors: Souza et al (2004), Carvalho & Dias (2007), Swarça et al (2008), Garcia & Moreira Filho (2008). CMA 3 staining on chromosomes of M. platanum displayed fluorescent signals on the short arm of a pair of sm chromosomes (Fig.…”

supporting

confidence: 81%

Chromosomal analyses in Megalonema platanum (Siluriformes: Pimelodidae), an endangered species from South American rivers

et al. 2011

Self Cite

View full text Add to dashboard Cite

This study presents chromosomal data of Megalonema platanum from rio Tibagi, Paraná, Brazil and from rio Paraná, Argentina. The diploid number was equal 54 with karyotype composition of 24m+16sm+2st+12a in both populations. The AgNOR sites were detected in the terminal position of a submetacentric pair of the two analyzed populations, coinciding with secondary constrictions on the short arm of pair 15. CMA 3 and FISH with 18S rDNA probe displayed fluorescent signals that correspond to the AgNOR sites and secondary constriction. The presence of a small acrocentric supernumerary chromosome can be observed in M. platanum from rio Tibagi, with centromeric heterochromatin. Others heterochromatic blocks were evidenced in the terminal position of some chromosome and one metacentric large chromosome pair, probably the first pair, showed an interstitial heterochromatin. In the population of the rio Paraná were still observed heterochromatic blocks in both ends in some chromosomes. This work brings for the first time cytogenetic date of M. platanum, which is a very rare species in the rio Paraná basin and may be endangered.Este estudo apresenta dados cromossômicos de Megalonema platanum do rio Tibagi, Paraná, Brasil e do rio Paraná, Argentina. O número diploide foi igual 54 com composição cariotípica de 24m+16sm+2st+12a em ambas populações. Os sítios AgNORs foram detectados na posição terminal de um par submetacêntrico das duas populações analisadas, coincidindo com constrição secundária no braço curto do par 15. CMA 3 e FISH com sonda de DNAr 18S exibiram sinais fluorescentes que correspondem aos sítios AgNORs e à constrição secundária. A presença de um pequeno cromossomo supranumerário acrocêntrico foi observado em M. platanum do rio Tibagi, com heterocromatina centromérica. Outros blocos heterocromáticos foram evidenciados na posição terminal de alguns cromossomos e um par cromossômico submetacêntrico grande, provavelmente o primeiro par, mostrou heterocromatina intersticial. Na população do rio Paraná foram observados ainda blocos heterocromáticos em ambas regiões terminais em alguns cromossomos. Este trabalho mostra pela primeira vez dados citogenéticos de M. platanum, que é uma espécie muito rara na bacia do rio Paraná e pode estar ameaçada de extinção.

show abstract

supporting

confidence: 81%

Chromosomal analyses in Megalonema platanum (Siluriformes: Pimelodidae), an endangered species from South American rivers

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since the 5S rDNA region is located on the same chromosome in the populations of I. labrosus from the Capivara Reservoir (Carvalho and Dias, 2007) and from the Tibagi River (this study), but in terminal and interstitial positions, respectively, it is possible that there was a paracentric inversion in a subtelocentric pair bearing 5S ribosomal genes. Probably, due to the fact that in most fish species these genes are located in an interstitial position, the location of the terminal 5S genes in the population from Capivara represents a derived condition.…”

Section: Discussionmentioning

confidence: 80%

“…Regions with similar CMA 3 positive staining were also seen in the chromosomes of I. labrosus from the Capivara Reservoir (Carvalho and Dias, 2007). Carvalho et al (2004) described the supernumerary chromosomes of I. labrosus from the Tibagi River as totally heterochromatic.…”

Section: Discussionmentioning

confidence: 84%

“…In the I. labrosus population of the Capivara Reservoir reviewed by Carvalho and Dias (2007), hybridisation with the 18S rDNA probe also showed signals corresponding to AgNORs in a pair of st-chromosomes and on the long arm in the terminal position, as in the population from the Tibagi River. The 5S rDNA location was different from that of the population studied herein, because the 5S ribosomal cistrons were in a terminal position on the long arm of a subtelocentric pair.…”

Section: Discussionmentioning

confidence: 88%

See 1 more Smart Citation

Cytogenetic analysis of the 18S, 5S rDNA and B chromosome of Iheringichthys labrosus (Lütken, 1874) (Siluriformes, Pimelodidae)

Laudicina²,

Giuliano-Caetano

et al. 2010

Braz. J. Biol.

View full text Add to dashboard Cite

Cytogenetic analyses of the location of 18S and 5S ribosomal DNAs, and the base composition of B chromosomes of Iheringichthys labrosus from Tibagi River, Paraná, Brazil, are provided. AgNORs were observed in the terminal position on the long arm of a subtelocentric chromosome pair. CMA 3 -positive staining was observed in some chromosomes, which besides being associated with NORs, were all DAPI-negative. Chromosome B showed a strong fluorescence with CMA 3. The concomitant use of 18S and 5S rDNA probes using the FISH technique revealed 18S ribosomal cistrons in a pair of subtelocentric chromosomes, on the long arm in the terminal position, coinciding with the AgNOR. The 5S sites were found in another subtelocentric pair, on the long arm in the interstitial region, near the centromere. The findings of the present study suggest that, although there are some more conserved cytogenetic characteristics, populations of I. labrosus may show their own characteristics.Keywords: supernumerary chromosome, catfish, FISH. Análise Citogenética de DNAr 18S, 5S e cromossomo B deIheringichthys labrosus (Lütken, 1874) (Siluriformes, Pimelodidae) ResumoForam realizadas análises citogenéticas em Iheringichthys labrosus do Rio Tibagi, Paraná, Brasil com a localização cromossômica dos DNAs ribossômicos 18S e 5S e a composição de bases de seus cromossomos B. As AgNORs foram observadas em posição terminal, no braço longo de um par de cromossomos subtelocêntricos. Marcações CMA 3 positivas foram observadas em alguns cromossomos e associadas com as RONs. Porém, todas estas marcações apresentaram-se DAPI negativas. O cromossomo B mostrou-se fortemente fluorescente com CMA 3 . O uso concomitante das sondas de DNAr 18S e 5S, através da técnica de FISH, revelou os cístrons ribossômicos em um par de cromossomos subtelocêntricos, em posição terminal do braço longo, coincidindo com a AgNOR. Os sítios 5S foram observados em outro par subtelocêntrico, em posição intersticial do braço longo, próximo ao centrômero. Os resultados observados no presente estudo sugerem que, embora existam algumas características citogenéticas mais conservadas, as populações de I. labrosus podem mostrar suas próprias características.Palavras-chave: cromossomo supranumerário, catfish, FISH.

show abstract

“…However, heteromorphism of the 18S rDNA is not uncommon in grasshoppers and variability in size, number, and location of sites has been described in several species (Souza and Moura, 2000;Cabral-de-Mello et al, 2010). Unequal crossing-over and deletions involving segments of chromosomes are usually considered as mechanisms that are responsible for the structural modifications of NORs (Carvalho and Dias, 2007). One of these events is probably responsible for the loss of the rDNA site in one of the homologues of the L 3 bivalent in the heterozygous individual of X. d. angulatus.…”

Section: Discussionmentioning

confidence: 99%

B chromosome prevalence and physical mapping of 18S rDNA and H4 histone sites in the grasshopper Xyleus discoideus angulatus (Romaleidae)

Machado¹,

Neto²,

Loreto³

et al. 2014

Genet. Mol. Res.

View full text Add to dashboard Cite

ABSTRACT. We sampled 11 natural populations of the grasshopper Xyleus discoideus angulatus in Northeastern Brazil to analyze B chromosome frequency and meiotic behavior. We observed a single large B chromosome, resembling the X chromosome, in 29 of the 402 specimens. Eight of the 11 populations had B chromosomes, with a rather broad geographical distribution, suggesting that this is an ancient polymorphism; significant differences were observed in B chromosome prevalence among the populations. Presence of the B chromosome was associated with increased frequency of macrospermatids. Fluorescent in situ hybridization revealed 18S rDNA sites in the pericentromeric regions of the X and L 3 chromosomes, although some populations had an additional locus on the M 4 chromosome. No variation was found for chromosome location of H4 histone genes, which were always observed in paracentromeric regions of the L 2 , M 4 and X chromosomes, a rather 7053 B chromosome in Xyleus discoideus angulatus ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (3): 7052-7060 (2014) unusual location compared to locations known from the families Acrididae and Proscopiidae. These B chromosomes lacked these two kinds of repetitive DNA, at least in amounts that can be visualized by fluorescent in situ hybridization, suggesting that these B chromosomes did not originate from any of the four chromosomes carrying rDNA or H4 histone genes.

show abstract

Interindividual size heteromorphism of NOR and chromosomal location of 5S rRNA genes in Iheringichthys labrosus

Abstract: ABSTRACT

Cited by 11 publications

References 15 publications

Chromosomal analyses in Megalonema platanum (Siluriformes: Pimelodidae), an endangered species from South American rivers

Chromosomal analyses in Megalonema platanum (Siluriformes: Pimelodidae), an endangered species from South American rivers

Cytogenetic analysis of the 18S, 5S rDNA and B chromosome of Iheringichthys labrosus (Lütken, 1874) (Siluriformes, Pimelodidae)

B chromosome prevalence and physical mapping of 18S rDNA and H4 histone sites in the grasshopper Xyleus discoideus angulatus (Romaleidae)

Contact Info

Product

Resources

About