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

ABSTRACT 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 compo...

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Main Authors: Carlos Alexandre Fernandes, Allan Kardec Moreira de Aguiar, Leonardo Marcel Paiz, Lucas Baumgärtner, Diovani Piscor, Vladimir Pavan Margarido
Format: Article
Language:English
Published: Sociedade Brasileira de Ictiologia
Series:Neotropical Ichthyology
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000300205&lng=en&tlng=en
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author Carlos Alexandre Fernandes
Allan Kardec Moreira de Aguiar
Leonardo Marcel Paiz
Lucas Baumgärtner
Diovani Piscor
Vladimir Pavan Margarido
author_facet Carlos Alexandre Fernandes
Allan Kardec Moreira de Aguiar
Leonardo Marcel Paiz
Lucas Baumgärtner
Diovani Piscor
Vladimir Pavan Margarido
author_sort Carlos Alexandre Fernandes
collection DOAJ
description ABSTRACT 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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spelling doaj.art-6101f91a22ff429b89c04fb462fa2e502022-12-22T01:53:16ZengSociedade Brasileira de IctiologiaNeotropical Ichthyology1982-022417310.1590/1982-0224-20190069S1679-62252019000300205First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)Carlos Alexandre FernandesAllan Kardec Moreira de AguiarLeonardo Marcel PaizLucas BaumgärtnerDiovani PiscorVladimir Pavan MargaridoABSTRACT 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.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000300205&lng=en&tlng=enAg-NORsC-bandingFish cytogeneticsKaryotype evolutionRepetitive sequences
spellingShingle Carlos Alexandre Fernandes
Allan Kardec Moreira de Aguiar
Leonardo Marcel Paiz
Lucas Baumgärtner
Diovani Piscor
Vladimir Pavan Margarido
First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
Neotropical Ichthyology
Ag-NORs
C-banding
Fish cytogenetics
Karyotype evolution
Repetitive sequences
title First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
title_full First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
title_fullStr First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
title_full_unstemmed First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
title_short First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
title_sort first chromosomal analysis of gymnorhamphichthys britskii the remarkable lowest diploid value within the family rhamphichthyidae gymnotiformes
topic Ag-NORs
C-banding
Fish cytogenetics
Karyotype evolution
Repetitive sequences
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000300205&lng=en&tlng=en
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