Karyotype diversity of four species of the incertae sedis group (Characidae) from different hydrographic basins: analysis of AgNORs, CMA3 and 18S rDNA

Mm, Mendes; R, da Rosa; Giuliano-Caetano, Lucia; Al, Dias Neto

doi:10.4238/2011.november.22.5

Cited by 16 publications

(20 citation statements)

References 33 publications

(40 reference statements)

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“…Thus, in O. hepsetus , 1 major rDNA site and an additional inactive site are located on the short arms of 2 distinct chromosome pairs, while O. jenynsii and O. pintoi show up to 8 rDNA clusters [Kavalco et al, 2005b;Centofante et al, 2006]. Also, conspicuous variation in the number of rDNA sites characterizes 2 analyzed species of Serrapinnus (Cheirodontinae) -1 rDNA site in S. heterodon and 3-4 sites (7 FISH signals) in S. piaba [Peres et al, 2008] -while Hyphessobrycon luetkenii and H. anisitsi (both 2n = 50, but noticeably diverse in formulae) show 3-4 and more than 6 rDNA-bearing chromosome pairs, respectively [Mendes et al, 2011].…”

Section: Interspecific and Intergeneric Variation In The Number And Lmentioning

confidence: 99%

Twenty Years of Physical Mapping of Major Ribosomal RNA Genes across the Teleosts: A Review of Research

Gornung

2013

Cytogenet Genome Res

113

100

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Molecular cytogenetic data on the number and position of 45S ribosomal RNA genes (rDNA; located in nucleolus organizing regions, NORs) detected by FISH in 330 species of 77 families and 22 orders of bony fishes (Teleostei) and, additionally, 11 species of basal ray-finned fishes are compiled and analyzed. The portion of species with single rDNA sites in the sample amounts to 72%. The percentage of species with multiple NORs decreases with increasing numbers of rDNA loci per genome, i.e. scarcely 3% of species carry 4 or more rDNA-bearing chromosome pairs. 43% of all rDNA sites analyzed occur terminally on the short arms of chromosomes or constitute them. In general, terminal rDNA sites account for 87% of all examined cases. Interspecific variation in the location of single rDNA sites among related taxa, polymorphisms of multiple NORs in some groups of teleosts and analytical outcomes on the subject are reviewed.

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Section: Interspecific and Intergeneric Variation In The Number And Lmentioning

confidence: 99%

Twenty Years of Physical Mapping of Major Ribosomal RNA Genes across the Teleosts: A Review of Research

Gornung

2013

Cytogenet Genome Res

113

100

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“…The karyotype macrostructure of N. venustus, including the modal diploid number of 2n=50, high number of biarmed chromosomes and a large metacentric pair (1 st pair), is observed in several species of Characidae. For instance, this pattern has been reported in Astyanax scabripinnis (Jenyns, 1842) (Moreira Filho & Bertollo, 1991), Hasemania nana (Lütken, 1875) (Moreira et al, 2007), Hyphessobrycon anisitsi (Eigenmann, 1907) (Mendes et al, 2011), Hollandichthys multifasciatus (Eigenmann & Norris, 1900) (Balen et al, 2013) and Rhoadsia altipinna Fowler, 1911 (Romero et al, 2015), being considered a plesiomorphic condition of characins (Scheel, 1973;Morelli et al, 1983). The presence of distinct types of chromosomes (m, sm, st, and a) without variation in diploid number suggests the occurrence of pericentric inversions, another common rearrangement in characins (Medrado et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…Accordingly, cytogenetic analyses have been carried out to address this issue, since chromosomal markers have proved to be useful for both systematic and evolutionary inferences in Neotropical fish (Blanco et al, 2010;Almeida et al, 2013;Piscor et al, 2015), including taxonomically problematic groups (Bellafronte et al, 2010;Mendes et al, 2011). Moreover, the availability of refined cytogenetic methods have allowed identifying population polymorphism and unique evolutionary units, even within morphologically similar groups (Bitencourt et al, 2011;Utsunomia et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Allopatric chromosomal variation in Nematocharax venustus Weitzman, Menezes & Britski, 1986 (Actinopterygii: Characiformes) based on mapping of repetitive sequences

et al. 2016

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Characiformes is the most cytogenetically studied group of freshwater Actinopterygii, but karyotypical data of several taxa remain unknown. This is the case of Nematocharax, regarded as a monotypic genus and characterized by marked sexual dimorphism. Therefore, we provide the first cytogenetic report of allopatric populations of Nematocharax venustus based on distinct methods of chromosomal banding and fluorescence in situ hybridization (FISH) with repetitive DNA probes (18S and 5S rDNA). The karyotype macrostructure was conserved in all specimens and populations, independently on sex, since they shared a diploid number (2n) of 50 chromosomes divided into 8m+26sm+14st+2a. The heterochromatin was mainly distributed at pericentromeric regions and base-specific fluorochrome staining revealed a single pair bearing GC-rich sites, coincident with nucleolar organizer regions (NORs). On the other hand, interpopulation variation in both number and position of repetitive sequences was observed, particularly in relation to 5S rDNA. Apparently, the short life cycles and restricted dispersal of small characins, such as N. venustus, might have favored the divergence of repetitive DNA among populations, indicating that this species might encompass populations with distinct evolutionary histories, which has important implications for conservation measures.Characiformes é o grupo de Actinopterygii de água doce mais estudado citogeneticamente, porém dados cariotípicos de vários taxa permanecem desconhecidos. Este é o caso de Nematocharax, considerado um gênero monotípico e caracterizado pelo acentuado dimorfismo sexual. Em vista disso, nós fornecemos a primeira descrição citogenética de populações alopátricas de Nematocharax venustus, baseada em métodos distintos de bandamento cromossômico e hibridação fluorescente in situ (FISH) com sondas de DNA repetitivo (DNAr 18S e 5S). A macroestrutura cariotípica mostrou-se conservada em todos os espécimes e populações, independentemente do sexo, uma vez que compartilharam um número diploide (2n) de 50 cromossomos dividido em 8m+26sm+14st+2a. A heterocromatina distribuiu-se principalmente nas regiões pericentroméricas e a coloração com fluorocromos base-específicos revelou um único par portador de sítios GC-ricos, coincidentes com as regiões organizadoras de nucléolo (RONs). Por outro lado, foi observada uma variação interpopulacional no número e na posição das sequências repetitivas, especialmente em relação ao DNAr 5S. Aparentemente, ciclos de vida curtos e dispersão restrita dos pequenos caracídeos, tal como N. venustus, podem ter favorecido a divergência do DNA repetitivo entre as populações, indicando que essa espécie pode englobar populações com distintas histórias evolutivas, o que tem implicações importantes para medidas de conservação.

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“…Therefore, little is known about the karyotype structure of this group. Some species which cytogenetic studies have been conducted are: 2n = 50 of Bryconamericus, 2n = 50 of Deuterodon stigmaturus, [Pazza, et al, 2006], 2n = 50 of Gymnocorymbus ternetzi [Arefjav, 1990], 2n = 50 of Moenkhausia sanctafilamenae [Mendes et al, 2011], 2n = 62 of Metynnis argenteus [Arai, 2011].…”

mentioning

confidence: 99%

Karyological Characterization of Three Fish Species (Family: Characidae)

Abu-Almaaty¹,

Hassan²,

Bahgat³

et al. 2017

Egypt. J. of Aquatic Biolo. and Fish.

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Karyotype diversity of four species of the incertae sedis group (Characidae) from different hydrographic basins: analysis of AgNORs, CMA3 and 18S rDNA

Cited by 16 publications

References 33 publications

Twenty Years of Physical Mapping of Major Ribosomal RNA Genes across the Teleosts: A Review of Research

Twenty Years of Physical Mapping of Major Ribosomal RNA Genes across the Teleosts: A Review of Research

Allopatric chromosomal variation in Nematocharax venustus Weitzman, Menezes & Britski, 1986 (Actinopterygii: Characiformes) based on mapping of repetitive sequences

Karyological Characterization of Three Fish Species (Family: Characidae)

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