A conserved karyotype of Sternopygus macrurus (Sternopygidae, Gymnotiformes) in the Amazon region: Differences from other hydrographic basins suggest cryptic speciation

Silva, Danillo dos Santos; Milhomem, Susana Suely Rodrigues; Souza, Augusto César Paes de; Pieczarka, Júlio César; Nagamachi, Cleusa Yoshiko

doi:10.1016/j.micron.2008.04.001

Cited by 20 publications

(20 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These discrepancies may arise from differences in the classification and position of the chromosomes in the karyotype. Our DAPI and CMA 3 staining results, which are the first such reports for this species, agree with the findings from similar studies in other Neotropical fishes [28-31]. More specifically, DAPI staining of the C-banding-positive regions showed that this CH is A-T rich, while CMA 3 staining of the NOR showed that the rDNA sequences are interspersed with G-C rich sequences.…”

Section: Discussionsupporting

confidence: 92%

Cytogenetic studies in Eigenmannia virescens (Sternopygidae, Gymnotiformes) and new inferences on the origin of sex chromosomes in the Eigenmannia genus

et al. 2009

View full text Add to dashboard Cite

BackgroundCytogenetic studies were carried out on samples of Eigenmannia virescens (Sternopygidae, Gymnotiformes) obtained from four river systems of the Eastern Amazon region (Para, Brazil).ResultsAll four populations had 2n = 38, with ZZ/ZW sex chromosomes (Z, acrocentric; W, submetacentric). Constitutive heterochromatin (CH) was found at the centromeric regions of all chromosomes. The W chromosome had a heterochromatic block in the proximal region of the short arm; this CH was positive for DAPI staining, indicating that it is rich in A-T base pairs. The nucleolar organizer region (NOR) was localized to the short arm of chromosome pair 15; this result was confirmed by fluorescent in situ hybridization (FISH) with human 45S rDNA, and CMA3 staining indicated that the region is G-C rich. FISH with telomeric probes did not show any evidence of interstitial telomeric sequences (ITS).ConclusionPrevious studies have shown that the species Eigenmannia sp. 2 and E. virescens have differentiated sex chromosomes, and diverse sex chromosome systems have been described for E. virescens specimens obtained from different Brazilian rivers. A comparative analysis of the present data and prior reports suggests that the sex chromosomes of Eigenmannia may have arisen independently in the different populations.

show abstract

Section: Discussionsupporting

confidence: 92%

Cytogenetic studies in Eigenmannia virescens (Sternopygidae, Gymnotiformes) and new inferences on the origin of sex chromosomes in the Eigenmannia genus

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The CH in Rhamphichthys prope rostratus and Rhamphichthys marmoratus is AT-rich (i.e., DAPI banding-positive), which is consistent with other species of Gymnotiformes (Milhomem et al 2007, 2008, Silva et al 2008, Silva et al 2009). The CH blocks found in pairs 4 and 12 of Rhamphichthys marmoratus and in pairs 3, 4 and 9 of Rhamphichthys prope rostratus can be used as cytogenetic markers for these species, as suggested for other Neotropical fish species (Almeida-Toledo 1998, Silva et al 2008).…”

Section: Discussionsupporting

confidence: 83%

“…The NOR was found on a secondary constriction and stained positive with CMA 3 as previously observed on other species (Pendáset al 1993, Fernandes et al 2005, Milhomem et al 2007, Silva et al 2008, De Souza et al 2009). Each of the species studied herein had a single NOR, but Rhamphichthys prope rostratus had a size heteromorphism in this region.…”

Section: Discussionsupporting

confidence: 78%

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

Silva¹,

Nagamachi²,

Silva³

et al. 2013

CCG

View full text Add to dashboard Cite

The family Rhamphichthyidae includes three genera: Rhamphichthys Müller et Troschel, 1846, Gymnorhamphichthys M. M. Ellis, 1912 and Iracema Triques, 1996. From this family, only the species Rhamphichthys hanni Meinken, 1937 has had its karyotype described. Here, we describe the karyotypes of two additional Rhamphichthys species: Rhamphichthys marmoratus Castelnau, 1855 from the Reserva de Desenvolvimento Sustentável Mamirauá, Amazonas state and Rhamphichthys prope rostratus Linnaeus, 1766 from Pará state, both in Brazil. Our karyotypic analyses demonstrated that the diploid number is conserved for the genus (2n = 50), but the karyotypic formulas (KFs) differed between Rhamphichthys marmoratus (44m/sm+6a) and Rhamphichthys prope rostratus (42m/sm+8a). In both species, the constitutive heterochromatin (CH) was located in the centromeric region of most chromosomes. Large heterochromatic blocks were found on the long arms of pairs 4 and 14 in Rhamphichthys marmoratus and on chromosomes 3, 4 and 19 in Rhamphichthys prope rostratus, which also has a heteromorphism in chromosome pair 1. The CH was DAPI positive, indicating that it is rich in AT base pairs. The Nucleolus Organizer Region (NOR) showed staining at a single location in both species: the long arm of pair 1 in Rhamphichthys marmoratus and the long arm of pair 12 in Rhamphichthys prope rostratus, where it showed a size heteromorphism. CMA3 staining coincided with that of Ag-NOR, indicating that the ribosomal genes contain interspaced GC-rich sequences. FISH with an 18S rDNA probe confirmed that there is only one NOR site in each species. These results can be used as potential cytogenetic markers for fish populations, and comparative analysis of the karyotypes of Hypopygus Hoedman, 1962, Rhamphichthys and Steatogenys Boulenger, 1898 suggests that the first two genera diverged later that the third.

show abstract

“…CH was found in the centromeric regions of virtually all chromosomes of the analyzed species. DAPI staining revealed that this CH is AT-rich, which is consistent with reports concerning other Gymnotiformes ( Milhomem et al , 2007 , 2008 , 2012a , b ; Silva et al , 2008 , 2009 ; Cardoso et al , 2011 ). The three species analyzed in the present study showed differing CH patterns, with several additional blocks in non-centromeric regions.…”

Section: Discussionsupporting

confidence: 91%

Chromosomal diversity in three species of electric fish (Apteronotidae, Gymnotiformes) from the Amazon Basin

et al. 2014

Self Cite

View full text Add to dashboard Cite

Cytogenetic studies were carried out on samples of Parapteronotus hasemani, Sternarchogiton preto and Sternarchorhamphus muelleri (Apteronotidae, Gymnotiformes) from the Amazon basin. The first two species exhibited both a 2n = 52 karyotype, but differed in their karyotypic formulae, distribution of constitutive heterochromatin, and chromosomal location of the NOR. The third species, Sternarchorhamphus muelleri, was found to have a 2n = 32 karyotype. In all three species the DAPI and chromomycin A3 staining results were consistent with the C-banding results and nucleolar organizer region (NOR) localization. The 18S rDNA probe confirmed that there was only one pair of ribosomal DNA cistron bearers per species. The telomeric probe did not reveal interstitial telomeric sequences (ITS). The karyotypic differences among these species can be used for taxonomic identification. These data will be useful in future studies of these fishes and help understanding the phylogenetic relationships and chromosomal evolution of the Apteronotidae.

show abstract

A conserved karyotype of Sternopygus macrurus (Sternopygidae, Gymnotiformes) in the Amazon region: Differences from other hydrographic basins suggest cryptic speciation

Cited by 20 publications

References 10 publications

Cytogenetic studies in Eigenmannia virescens (Sternopygidae, Gymnotiformes) and new inferences on the origin of sex chromosomes in the Eigenmannia genus

Cytogenetic studies in Eigenmannia virescens (Sternopygidae, Gymnotiformes) and new inferences on the origin of sex chromosomes in the Eigenmannia genus

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

Chromosomal diversity in three species of electric fish (Apteronotidae, Gymnotiformes) from the Amazon Basin

Contact Info

Product

Resources

About