Cytogenetic data on Astyanax jacuhiensis (Characidae) in the lago Guaíba and tributaries, Brazil

Pacheco, Rosiley Berton; Giuliano-Caetano, Lúcia; Júlio, Horácio Ferreira; Dias, Ana Lúcia

doi:10.1590/s1679-62252010000300013

Cited by 10 publications

(17 citation statements)

References 18 publications

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“…, indicating that GC-rich regions are interspersed with ribosomal sites. This relationship has already been reported for the bimaculatus species complex (Domingues et al 2007;Pacheco et al 2010;Silva et al 2012). However, CMA 3…”

Section: Discussionsupporting

confidence: 81%

“…Thus, the presence of single NORs in A. asuncionensis and in some individuals of A. altiparanae may indicate a close phylogenetic relationship with other members of the bimaculatus species complex that also exhibit this pattern, such as A. lacustris (Peres et al 2008(Peres et al , 2012, Astyanax aff. bimaculatus (Kavalco et al 2011) and A. jacuhiensis (Pacheco et al 2010;Silva et al 2012).…”

Section: Discussionmentioning

confidence: 99%

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Chromosomal characterization in two species of an Astyanax bimaculatus complex (Characidae, Characiformes) using different techniques of chromosome banding

et al. 2015

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Astyanax has been the subject of extensive cytogenetic studies due to its wide karyotypic diversity. This genus comprises species complexes, namely groups of fish of difficult morphological differentiation, such as the bimaculatus complex, which includes the characids with a rounded humeral spot. Thence, the present study proposed to accomplish a cytogenetic characterization of two species of this complex: A. asuncionensis and A. altiparanae, aiming to find chromosomal markers that differentiate these species, as well as achieve a better understanding of the karyotype evolution in the genus. For this we used different techniques of chromosome banding as C-banding, impregnation by silver nitrate, fluorochrome staining and FISH with 18S rDNA probe. This is the first cytogenetic study in A. asuncionensis, from Miranda river, which presented 2n = 50 and 18 m + 22sm + 6st + 4a (FN = 96) and single NORs. The populations of A. altiparanae also presented 2n = 50, but with different karyotypic formulae: the population of the Quexada river presented 16 m + 24sm + 4st + 6a (FN = 94) and the Esperança stream and Jacutinga river showed 16 m + 20sm + 4st + 10a (FN = 90). All analyzed populations showed an interindividual variation in the number and location of the nucleolar organizer regions (NORs). Single and multiple NORs were detected either by impregnation with silver nitrate or by FISH with 18S rDNA probe. After C-banding, the two species differed in relation to the composition and heterochromatin distribution. The meiotic cells of A. altiparanae male individuals were also analyzed, showing that, despite the high karyotype variability, chromosome pairing occurs normally. The data show that A. altiparanae and A. asuncionensis share some characteristics with other species of the bimaculatus complex, suggesting a close phylogenetic relationship among those species. However, some features can be used as differentiation chromosomal markers in altiparanae/asuncionensis morphotypes, which could result from a natural speciation process.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Chromosomal characterization in two species of an Astyanax bimaculatus complex (Characidae, Characiformes) using different techniques of chromosome banding

et al. 2015

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“…Available cytogenetic data reveal diploid chromosome numbers within Astyanax that vary from 2n = 36 in Astyanax schubarti Britski, 1964 (Morelli et al 1983) to 2n = 50, as observed Astyanax scabripinnis , Astyanax fasciatus , Astyanax altiparanae and Astyanax jacuhiensis (Cope, 1894) (Souza and Moreira-Filho 1995, Artoni et al 2006, Ferreira-Neto et al 2009, Pacheco et al 2010). Martinez et al (2012) carried out a review of twenty populations of Astyanax altiparanae , observing intraspecific differences in the karyotypes, and the number and position of the nucleolus organizing regions (NORs).…”

Section: Introductionmentioning

confidence: 93%

Basic cytogenetics and physical mapping of ribosomal genes in four Astyanax species (Characiformes, Characidae) collected in Middle Paraná River, Iguassu National Park: considerations on taxonomy and systematics of the genus

Paiz¹,

Baumgärtner²,

Graça³

et al. 2015

CCG

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Karyotypes and chromosomal characteristics of both minor and major rDNAs in four fish species known popularly as “lambaris”, namely Astyanax abramis (Jenyns, 1842), Astyanax asuncionensis Géry, 1972, Astyanax correntinus (Holmberg, 1891) and Astyanax sp. collected from downstream of the Iguassu Falls (Middle Paraná River basin), preservation area of the Iguassu National Park, were analyzed by conventional and molecular protocols. Astyanax abramis had diploid chromosome number 2n=50 (4m+30sm+8st+8a) and single AgNORs (pair 22), Astyanax asuncionensis had 2n=50 (8m+24sm+6st+12a) and single AgNORs (pair 20), Astyanax sp. had 2n=50 (4m+26sm+8st+12a) and single AgNORs (pair 25), and Astyanax correntinus had 2n=36 (12m+16sm+2st+6a) and multiple AgNORs (pairs 12, 15, 16, 17). FISH with 18S rDNA showed a single site for Astyanax abramis, Astyanax asuncionensis and Astyanax sp. and multiple for Astyanax correntinus (14 sites). FISH with 5S rDNA showed single 5S-bearing loci chromosome pair only for Astyanax asuncionensis and multiple for Astyanax abramis (four sites), Astyanax correntinus (five sites) and Astyanax sp. (four sites). Distinct distribution patterns of heterochromatin were observed for karyotypes of all species, with the exception of the first acrocentric chromosome pair characterized by centromeric, interstitial-proximal and telomeric blocks of heterochromatin on the long arm, which may represent homeology between karyotypes of Astyanax abramis and Astyanax asuncionensis. Our study showed species-specific characteristics which can serve in diagnosis and differentiation between Astyanax abramis and Astyanax asuncionensis, considered cryptic species, as well as strengthening the occurrence of a species of Astyanax not yet described taxonomically. In addition, the data obtained from first cytogenetic studies in Astyanax correntinus suggest a high similarity with Astyanax schubarti Britski, 1964, suggesting that these species may belong to the same morphological group and that can be phylogenetically related.

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“…The diploid number in the genus ranges from 36 chromosomes in Astyanax schubarti Britski, 1964(Morelli et al 1983 to 50 chromosomes in A. scabripinnis, A. fasciatus, A. altiparanae and A. jacuhiensis (Cope, 1894) (Maistro et al 1998;Artoni et al 2006;Hashimoto et al 2008;Pacheco et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Interpopulational comparative cytogenetics analysis among three Astyanax (Characiformes: Incertae Sedis) species of two streams of upper Paraná River basin, Brazil

2014

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Populations of Astyanax paranae, Astyanax fasciatus and Astyanax altiparanae collected from the Pindorama and Lopei streams (upper Paraná river basin, Brazil) were cytogenetically studied, checking for chromosomal differentiation and the evolutionary trend in the three species. Forty-eight chromosomes (8m + 20sm + 10st + 10a) were observed in both populations of Astyanax paranae. Astyanax fasciatus exhibited 50 chromosomes (8m + 18sm + 10st + 14a, Pindorama stream; 8m + 14sm + 12st + 16a, Lopei stream). The diploid number for A. altiparanae was 50 chromosomes in both populations (6m + 30sm + 4st + 10a). The three studied species exhibited multiple AgNORs with differences among the populations of A. paranae and A. fasciatus. Regarding the heterochromatin distribution, interpopulational differences were observed in the three species. The data of the present study demonstrate that both A. paranae and A. fasciatus exhibit karyotypical interpopulational differences more conspicuous than A. altiparanae populations, probably due to the characteristics that restricted both the A. paranae and the A. fasciatus to the upper portion of the streams, leading to the fixation of different chromosomal rearrangements in the populations. However, the absence of conspicuos interpopulational karyotypical differences in A. altiparanae suggests a gene flow between both populations. In the present study, the role of the streams as an environment which maintains the diversity of fish with different genetic pools became evident.

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Cytogenetic data on Astyanax jacuhiensis (Characidae) in the lago Guaíba and tributaries, Brazil

Cited by 10 publications

References 18 publications

Chromosomal characterization in two species of an Astyanax bimaculatus complex (Characidae, Characiformes) using different techniques of chromosome banding

Chromosomal characterization in two species of an Astyanax bimaculatus complex (Characidae, Characiformes) using different techniques of chromosome banding

Basic cytogenetics and physical mapping of ribosomal genes in four Astyanax species (Characiformes, Characidae) collected in Middle Paraná River, Iguassu National Park: considerations on taxonomy and systematics of the genus

Interpopulational comparative cytogenetics analysis among three Astyanax (Characiformes: Incertae Sedis) species of two streams of upper Paraná River basin, Brazil

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