Remarkable karyotypic homogeneity in a widespread tropical fish species: <i>Hoplosternum littorale</i> (Siluriformes, Callichthyidae)

Almeida, Josivanda Santos; Affonso, P.R.A.M.; Dias, Ana Lúcia

doi:10.1111/j.1095-8649.2012.03387.x

Cited by 8 publications

(4 citation statements)

References 18 publications

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“…39 Few examples of species presenting multiple 5S rDNA cistrons (often located in two pairs) are available in this order, such as the callichthyid Hoplosternum littorale. 40,41 Multiple 5S rDNA sites were also detected in C. callichthys from this study, although involving a higher and variable number of marked chromosomes (eight to 12). On the other hand, the nonsyntenic distribution of 5S and 18S rDNA (NORs) in the studied species has been commonly reported in fish.…”

Section: Variation Of Ribosomal Genessupporting

confidence: 49%

Chromosomal Variation in the Tropical Armored CatfishCallichthys Callichthys(Siluriformes, Callichthyidae): Implications for Conservation and Taxonomy in a Species Complex from a Brazilian Hotspot

et al. 2013

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The Neotropical catfish family Callichthyidae is characterized by wide karyotype variation, although reports are restricted to a few species/populations. This work provides new chromosomal information in two populations of armoured catfish (Callichthys callichthys) within the Atlantic forest boundaries in northeastern Brazil. Both populations of C. callichthys presented 2n=54 (16 metacentric, 24 submetacentric, 6 subtelocentric, and 8 acrocentric chromosomes) with occurrence of a metacentric B macrochromosome, reported for the first time in "2n=54" karyomorph. The lack of heterochromatin in the supernumerary chromosome suggests a recent origin of Bs with a significant difference in their frequency (p<0.05) between localities. Contrasting to the predominance of single nucleolus organizer regions (NORs) in other populations from South America, a remarkable polymorphism of 18S rDNA and GC-rich sites was detected, inasmuch as NOR phenotypes were unique for each individual, comprising up to 13 NOR-bearing chromosomes. The 5S rDNA was also mapped onto multiple chromosomes nonsyntenic to NORs. Such divergence in a number of NORs and occurrence of an euchromatic B chromosome in relation to other karyomorphs reinforces the divergent evolution of C. callichthys populations. Furthermore, these results also support central and drier Atlantic forest areas in northeastern Brazil as a biodiversity hotspot.

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Section: Variation Of Ribosomal Genessupporting

confidence: 49%

Chromosomal Variation in the Tropical Armored CatfishCallichthys Callichthys(Siluriformes, Callichthyidae): Implications for Conservation and Taxonomy in a Species Complex from a Brazilian Hotspot

et al. 2013

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“…Lepthoplosternum has six species described: L. allocated, the physical mapping of the 5S and 18S ribosomal genes is described only for two populations of Hoplosternum littorale (Pazza et al 2005;Almeida et al 2012). Hypotheses about the evolution of 5S and 18S rDNA genes in Callichthyinae are difficult to form because of the scarcity of data for the remaining genera of this subfamily.…”

Section: Introductionmentioning

confidence: 99%

Karyotypic diversity and chromosome evolution in the armored catfishes Callichthyinae (Siluriformes, Callichthyidae)

et al. 2014

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The Callichthyinae subfamily is composed of five genera with a small number of described species. Molecular cytogenetics studies show the scarcity of records for this subfamily. The aim of the present study was to employ cytogenetic parameters in the analysis of three species belonging to the subfamily Callichthyinae sampled from the Paraná River (Brazil). Callichthys callichthys had 2n = 56 chromosomes (26 m-sm + 30 st-a); Lepthoplosternum pectorale had 2n = 64 chromosomes (8 m-sm + 56 st-a); and Hoplosternum littorale had 2n = 60 chromosomes (8 m-sm + 52 st-a). Regarding the location of the nucleolar organizer regions (NORs) (Ag-staining and 18S rDNA-FISH), different situations were found: single NORs in H. littorale and C. callichthys; multiple NORs in L. pectorale, with intra-individual and inter-individual variation. Heterochromatin was observed in the centromeric region in the chromosomes of the three species. Equilocal, interstitial bands were also found in H. littorale. Physical mapping of 5S ribosomal genes by FISH shows eight 5S rDNA sites in C. callichthys; four 5S rDNA sites in H. littorale and six 5S rDNA sites in L. pectorale. Using cytogenetic markers (diploid number, chromosome formula, NORs, heterochromatin distribution pattern and 5S and 18S rDNA sites), the chromosomal evolution in Callichthyinae is presented: Callichthys shows mostly basal chromosomal conditions, with mostly derived chromosomal conditions verified for the Hoplosternum-Dianema clade and Megalechis-Lepthoplosternum clade.

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“…[46][47][48] The adaptability of the tamoatá may be partly related to its heterochromatin composition and location, which may be differentially organized according to the environment in which the individual lives. Three patterns of heterochromatin distribution from different regions of Brazil and Venezuela are found: (a) centromeric and interstitial blocks 44,49,50 ; (b) subterminal and interstitial blocks 51 ; and (c) centromeric, pericentromeric, and interstitial blocks. 52 However, cytogenetic data available for the species have shown no differences in the karyotype macrostructure between individuals collected from natural and polluted environments, although several questions regarding their genomic organization remain unanswered.…”

Section: Introductionmentioning

confidence: 99%

“…Tamoatá does not have migratory habits 43,44 and is also considered a cryptic species found in different basins of South America with a high genetic diversity. 45 Furthermore, these fish have great commercial value because the riverside population commonly uses them as a food source.…”

Section: Introductionmentioning

confidence: 99%

Genomic Organization Under Different Environmental Conditions:Hoplosternum Littoraleas a Model

et al. 2016

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The Amazon has abundant rivers, streams, and floodplains in both polluted and nonpolluted environments, which show great adaptability. Thus, the goal of this study was to map repetitive DNA sequences in both mitotic chromosomes and erythrocyte micronuclei of tamoatás from polluted and nonpolluted environments and to assess the possible genotoxic effects of these environments. Individuals were collected in Manaus, Amazonas (AM), and submitted to classical and molecular cytogenetic techniques, as well as to a blood micronucleus test. Diploid number equal to 60 chromosomes are present in all individuals, with 18S ribosomal DNA sites present in one chromosome pair and no interstitial telomeric sites on chromosomes. The micronucleus test showed no significant differences in pairwise comparisons between environments or collection sites, but the Rex3 retroelement was dispersed on the chromosomes of individuals from unpolluted environments and compartmentalized in individuals from polluted environments. Divergent numbers of 5S rDNA sites are present in individuals from unpolluted and polluted environments. The mapping of repetitive sequences revealed that micronuclei have different compositions both intra-and interindividually that suggests different regions are lost in the formation of micronuclei, and no single fragile region undergoes breaks, although repetitive DNA elements are involved in this process.

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Remarkable karyotypic homogeneity in a widespread tropical fish species: Hoplosternum littorale (Siluriformes, Callichthyidae)

Cited by 8 publications

References 18 publications

Chromosomal Variation in the Tropical Armored CatfishCallichthys Callichthys(Siluriformes, Callichthyidae): Implications for Conservation and Taxonomy in a Species Complex from a Brazilian Hotspot

Chromosomal Variation in the Tropical Armored CatfishCallichthys Callichthys(Siluriformes, Callichthyidae): Implications for Conservation and Taxonomy in a Species Complex from a Brazilian Hotspot

Karyotypic diversity and chromosome evolution in the armored catfishes Callichthyinae (Siluriformes, Callichthyidae)

Genomic Organization Under Different Environmental Conditions:Hoplosternum Littoraleas a Model

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