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

Silva, de JesusIsac; FerreiraMilena,; Garcia, Caroline; Braga, R.A; Alves-Gomes, José Antônio; FeldbergEliana,

doi:10.1089/zeb.2016.1281

Cited by 7 publications

(9 citation statements)

References 34 publications

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“…Thus, understanding the neutralization of the gene flow or the locking for factors that prevent gene exchanges, such as vicariance, gene mutations and chromosomal rearrangements, are important steps to explain evolutionary processes that frequently lead to speciation ( Turelli et al, 2001 ; Kawakami et al, 2011 ). Indeed, it is well-known that mutations and chromosome rearrangements can be fixated by genetic drift and, more easily, in small and isolated populations ( Jesus et al, 2016 ), as is the case for the B . coracoideus populations here investigated.…”

Section: Discussionmentioning

confidence: 99%

The Bunocephalus coracoideus Species Complex (Siluriformes, Aspredinidae). Signs of a Speciation Process through Chromosomal, Genetic and Ecological Diversity

et al. 2017

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Bunocephalus is the most species-rich Aspredinidae genus, corresponding to a monophyletic clade with 13 valid species. However, many species have their classification put in question. Here, we analyzed individuals from four Amazonian populations of Bunocephalus coracoideus by cytogenetic and molecular procedures. The geographic distribution, genetic distances and karyotype data indicate that each population represents an Evolutionary Significant Unit (ESU). Cytogenetic markers showed distinct 2n and karyotype formulas, as well as different numbers and locations of the rDNA sites among ESUs. One of such populations (ESU-D) highlighted an extensive polymorphic condition, with several cytotypes probably due to chromosomal rearrangements and meiotic non-disjunctions. This resulted in several aneuploid karyotypes, which was also supported by the mapping of telomeric sequences. Phylograms based on Maximum Likelihood (ML) and Neighbor Joining (NJ) analyses grouped each ESU on particular highly supported clades, with the estimation of evolutionary divergence indicating values being higher than 3.8–12.3% among them. Our study reveals a huge degree of chromosomal and genetic diversity in B. coracoideus and highly points to the existence of four ESUs in allopatric and sympatric speciation processes. In fact, the high divergences found among the ESUs allowed us to delimitate lineages with taxonomic uncertainties in this nominal species.

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Section: Discussionmentioning

confidence: 99%

The Bunocephalus coracoideus Species Complex (Siluriformes, Aspredinidae). Signs of a Speciation Process through Chromosomal, Genetic and Ecological Diversity

et al. 2017

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“…In G. britskii, the 5S rDNA is located in a single chromosome pair and nonsyntenic with the 18S rDNA sites, a common characteristic of several fish groups (Pisano et al, 2007). Simple 5S rDNA sites were also observed in karyotypes of M. bilineatus, but in only one chromosome of the 12 th pair in males showed synteny between the 18S rDNA and 5S rDNA sites (de Jesus et al, 2016). Moreover, in M. bilineatus the 5S rDNA cistrons are located in the terminal region, while in G. britskii these cistrons are located in the interstitial position.…”

Section: Discussionmentioning

confidence: 93%

“…Compared to other rhamphichthyids that have 2n = 50, the karyotype of G. britskii suggested a reduction in the 2n, indicating that chromosome rearrangements, such as centric fusions that can alter the chromosome number may have occurred during the diversification of this group. 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).…”

Section: Discussionmentioning

confidence: 99%

“…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%

“…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%

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

Cited by 7 publications

References 34 publications

The Bunocephalus coracoideus Species Complex (Siluriformes, Aspredinidae). Signs of a Speciation Process through Chromosomal, Genetic and Ecological Diversity

The Bunocephalus coracoideus Species Complex (Siluriformes, Aspredinidae). Signs of a Speciation Process through Chromosomal, Genetic and Ecological Diversity

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

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

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