Karyotypic similarities between two species of Rhamphichthys (Rhamphichthyidae, Gymnotiformes) from the Amazon basin

Silva, Patrícia Corrêa da; Nagamachi, Cleusa Yoshiko; Silva, Danillo dos Santos; Milhomem, Susana Suely Rodrigues; Cardoso, Adauto Lima; Oliveira, Jonas Alves de; Pieczarka, Júlio César

doi:10.3897/compcytogen.v7i4.4366

Cited by 8 publications

(10 citation statements)

References 30 publications

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“…3a, box), thus characterizing a simple NORs system in G. britskii. Similar pattern was observed in karyotypes of S. duidae, S. elegans (Cardoso et al, 2011), R. hahni, R. pantherinus and R. rostratus (Mendes et al, 2012;Silva et al, 2013). A single chromosome pair with NORs sites is thought to be a plesiomorphic characteristic of the Rhamphichthyidae.…”

Section: Discussionsupporting

confidence: 68%

“…Chromosome fusions were identified as important events in the diversification of Hypopomidae (the sister group of Rhamphichthyidae), in which the diploid number varies between 36 chromosomes, as in B. brevirostris, and 48 chromosomes, as in M. bilineatus (de Jesus et al, 2016;Batista et al, 2017;Cardoso et al, 2018). In Rhamphichthyidae, the chromosomic data of G. britskii alter the paradigm of karyotype evolution characterized by 2n conservation (50 chromosomes) and chromosome inversions (Cardoso et al, 2011;Mendes et al, 2012;Silva et al, 2013). Nonetheless, more rhamphichthyid species need to be cytogenetically analyzed to confirm this hypothesis (diversification by chromosome fusions).…”

Section: Discussionmentioning

confidence: 99%

“…No cytogenetic information is available for species of Gymnorhamphichthys. Among the other Rhamphichthyidae, cytogenetic information is available only for Hypopygus lepturus Hoedeman, 1962(Almeida-Toledo, 1978, Steatogenys duidae (La Monte, 1929), S. elegans (Steindachner, 1880) (Cardoso et al, 2011), Rhamphichthys hahni (Meinken, 1937), R. pantherinus Castelnau, 1855 (cited as R. marmoratus) and R. rostratus (Linnaeus, 1766) (Mendes et al, 2012;Silva et al, 2013). Among the Hypopomidae, it is available for Hypopomus artedi (Kaup, 1856) (Almeida-Toledo, 1978, eight Brychyhypopomus species (Almeida-Toledo, 1978;Mendes et al, 2012;Cardoso et al, 2018) and Microsternarchus bilineatus Fernández-Yépez, 1968(de Jesus et al, 2016Batista et al, 2017).…”

Section: First Chromosomal Analysis Of Gymnorhamphichthys Britskiimentioning

confidence: 99%

“…There are still few cytogenetic studies regarding Rhamphichthyoidea, but they show that these species present great differences in relation to the number of chromosomes and karyotype macrostructure. In Rhamphichthyidae all species had 2n = 50 chromosomes but differed in their karyotypes (Almeida-Toledo, 1978;Cardoso et al, 2011;Mendes et al, 2012;Silva et al, 2013). Among the Hypopomidae, the diploid number ranged from 36 (Brachyhypopomus brevirostris (Steindachner, 1868)) to 48 (M. bilineatus) chromosomes (de Jesus et al, 2016;Batista et al, 2017;Cardoso et al, 2018).…”

Section: First Chromosomal Analysis Of Gymnorhamphichthys Britskiimentioning

confidence: 99%

“…The physical mapping of ribosomal DNAs, especially 5S and 18S rDNAs, has been frequently used by cytogenetic studies on Neotropical fish, including fishes of the order Gymnotiformes (Fernandes et al, 2017a,b) to assist the clarification of taxonomic, biogeographical and phylogenetic problems. In Rhamphichthyidae, cytogenetic studies about the distribution of ribosomal genes (18S rDNA) are restricted to karyotypes of S. duidae, S. elegans (Cardoso et al, 2011), R. hahni, R. pantherinus and R. rostratus (Mendes et al, 2012;Silva et al, 2013), demonstrating only one chromosome pair bearing these clusters in all species.…”

Section: First Chromosomal Analysis Of Gymnorhamphichthys Britskiimentioning

confidence: 99%

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First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)

et al. 2019

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Gymnorhamphichthys britskii is a Neotropical electric fish of family Rhamphichthyidae described from the Paraná-Paraguay system. This study reports the first karyotypic description of G. britskii collected from the upper Paraná river basin, which presented 2n=38 chromosomes, karyotype composed of 14 metacentric, 8 submetacentric, 2 subtelocentric and 14 acrocentric chromosomes, and fundamental number as 62 for both sexes. Heteromorphic sex chromosomes were absent. A single pair of nucleolar organizing regions (NORs) was detected in the submetacentric chromosome pair number 9 by silver staining and confirmed by the 18S rDNA probe. The 5S rDNA was located in a single chromosome pair. Heterochromatic regions were clearly observed in the short arms of the NOR-bearing chromosome pair and in the telomeric positions of most acrocentric chromosomes. Besides the present data are valuable to help in understanding karyotypic evolution in Rhamphichthyidae, data from NORs confirmed the tendency of this family in presenting simple NORs sites, similar to the other Gymnotiformes clades. Yet, the presence of a large heterochromatic block in the NOR-bearing chromosome can be used as cytogenetic markers for G. britskii, and that centric fusions appear to be an important mechanism in the karyotype evolution and differentiation among Gymnotiformes species.

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Section: Discussionsupporting

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Section: First Chromosomal Analysis Of Gymnorhamphichthys Britskiimentioning

confidence: 99%

Section: First Chromosomal Analysis Of Gymnorhamphichthys Britskiimentioning

confidence: 99%

Section: First Chromosomal Analysis Of Gymnorhamphichthys Britskiimentioning

confidence: 99%

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First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)

et al. 2019

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First Cytogenetic Description of Microsternarchus bilineatus (Gymnotiformes: Hypopomidae) from Negro River (Brazilian Amazon)

et al. 2016

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Microsternarchus bilineatus is a neotropical electric fish species widely distributed in Amazonian ecosystems. This work reports the first karyotypic description of the species M. bilineatus, which presented 2n = 48 chromosomes, with a distinct karyotypic formula between the sexes: males with 21 metacentric (m)/submetacentric (sm) + 27 subtelocentric (st)/acrocentric (a) and fundamental number (FN) = 69 and females with 20 m/sm + 28 st/a and FN = 68. We found a probable recent sex system of XX/XY type. The nucleoli organizer regions (NORs) were multiple terminally located, and the heterochromatic blocks were mostly pericentromeric. The 18S rDNA markings confirmed NORs and their distinction between sexes, which suggested some differential role of this gene related to gender in this species. The 5S rDNA presented terminal markings on a single chromosome pair, with no distinction between sexes, and the telomeric probes have shown a uniform pattern in males and females.

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The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes

et al. 2017

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Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco River basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Bragança, Pará, Brazil). The diploid number of 48 chromosomes (14 meta-submetacentric/34 subtelo-acrocentric) is found for males and females, with an XX/XY sex chromosome system. The nucleolar organizer region is found in the short arm of pair 9. Constitutive heterochromatin occurs in the pericentromeric region of all chromosomes, in the distal region of 3p, 5p, 7p, 8q, 9q, 16q, and Xq, in the interstitial region in 2p, 10q, 11q, and 12q and all along 4p, and in a large block of the Y chromosome. These results indicate extensive karyotype divergence between this population and samples from Igarapé Tarumã Grande (Negro River, Amazonas, Brazil) studied by other researchers. Moreover, despite the diversity of sex chromosome systems found in Gymnotiformes, the XX/XY sex chromosome system of M. aff. bilineatus is the first case of Y chromosome degeneration in this order. The present data are valuable to help understand karyotype evolution in Hypopomidae.

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Karyotypic similarities between two species of Rhamphichthys (Rhamphichthyidae, Gymnotiformes) from the Amazon basin

Cited by 8 publications

References 30 publications

First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)

First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)

First Cytogenetic Description of Microsternarchus bilineatus (Gymnotiformes: Hypopomidae) from Negro River (Brazilian Amazon)

The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes

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