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First description of the karyotype and localization of major and minor ribosomal genes in Rhoadsiaaltipinna Fowler, 1911 (Characiformes, Characidae) from Ecuador.

Sánchez-Romero O, Abad CQ, Cordero PQ, de Sene VF, Nirchio M, Oliveira C - Comp Cytogenet (2015)

Bottom Line: The first metacentric pair presents two well-defined heterochromatic blocks in paracentromeric position, near the centromere.Impregnation with silver nitrate showed a single pair of Ag-positive NORs localized at terminal regions of the short arms of the subtelocentric chromosome pair number 12.Comparison of results here reported with those available on other Characidae permit to hypothesize that the presence of a very large metacentric pair might represent a unique and derived condition that characterize one of four major lineages molecularly identified in this family.

View Article: PubMed Central - PubMed

Affiliation: Universidad Técnica de Machala, El Oro, Ecuador ; Universidad Nacional Mayor de San Marcos UNMSM, Lima, Perú

ABSTRACT
Karyotypic features of Rhoadsiaaltipinna Fowler, 1911 from Ecuador were investigated by examining metaphase chromosomes through Giemsa staining, C-banding, Ag-NOR, and two-color-fluorescence in situ hybridization (FISH) for mapping of 18S and 5S ribosomal genes. The species exhibit a karyotype with 2n = 50, composed of 10 metacentric, 26 submetacentric and 14 subtelocentric elements, with a fundamental number FN=86 and is characterized by the presence of a larger metacentric pair (number 1), which is about 2/3 longer than the average length of the rest of the metacentric series. Sex chromosomes were not observed. Heterochromatin is identifiable on 44 chromosomes, distributed in paracentromeric position near the centromere. The first metacentric pair presents two well-defined heterochromatic blocks in paracentromeric position, near the centromere. Impregnation with silver nitrate showed a single pair of Ag-positive NORs localized at terminal regions of the short arms of the subtelocentric chromosome pair number 12. FISH assay confirmed these localization of NORs and revealed that minor rDNA clusters occur interstitially on the larger metacentric pair number 1. Comparison of results here reported with those available on other Characidae permit to hypothesize that the presence of a very large metacentric pair might represent a unique and derived condition that characterize one of four major lineages molecularly identified in this family.

No MeSH data available.


Related in: MedlinePlus

Chromosomes of Rhoadsiaaltipinna (male). (a) Giemsa-stained karyotype, M/SM: Metacentric/Submetacentric; ST: Subtelocentric; A: Acrocentric; (b) C-band somatic metaphases - thin arrows indicate chromosomes without positive C-bands and thick arrows point to heterochromatin on the pair number 1; (c) Silver-stained metaphase. Arrows indicate Ag-NORs. Bar =10 µm.
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Figure 2: Chromosomes of Rhoadsiaaltipinna (male). (a) Giemsa-stained karyotype, M/SM: Metacentric/Submetacentric; ST: Subtelocentric; A: Acrocentric; (b) C-band somatic metaphases - thin arrows indicate chromosomes without positive C-bands and thick arrows point to heterochromatin on the pair number 1; (c) Silver-stained metaphase. Arrows indicate Ag-NORs. Bar =10 µm.

Mentions: The analysis of 234 mitotic metaphase cells of Rhoadsiaaltipinna revealed a diploid number of 2n=50 chromosomes. The karyotype consisted of 10 metacentric, 26 submetacentric and 14 subtelocentric elements, with a fundamental number FN=86 (Fig. 2a). The larger metacentric pair (number 1), is about 2/3 longer than the average length of the rest of the metacentric series. No differences between chromosome complements were found.


First description of the karyotype and localization of major and minor ribosomal genes in Rhoadsiaaltipinna Fowler, 1911 (Characiformes, Characidae) from Ecuador.

Sánchez-Romero O, Abad CQ, Cordero PQ, de Sene VF, Nirchio M, Oliveira C - Comp Cytogenet (2015)

Chromosomes of Rhoadsiaaltipinna (male). (a) Giemsa-stained karyotype, M/SM: Metacentric/Submetacentric; ST: Subtelocentric; A: Acrocentric; (b) C-band somatic metaphases - thin arrows indicate chromosomes without positive C-bands and thick arrows point to heterochromatin on the pair number 1; (c) Silver-stained metaphase. Arrows indicate Ag-NORs. Bar =10 µm.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488973&req=5

Figure 2: Chromosomes of Rhoadsiaaltipinna (male). (a) Giemsa-stained karyotype, M/SM: Metacentric/Submetacentric; ST: Subtelocentric; A: Acrocentric; (b) C-band somatic metaphases - thin arrows indicate chromosomes without positive C-bands and thick arrows point to heterochromatin on the pair number 1; (c) Silver-stained metaphase. Arrows indicate Ag-NORs. Bar =10 µm.
Mentions: The analysis of 234 mitotic metaphase cells of Rhoadsiaaltipinna revealed a diploid number of 2n=50 chromosomes. The karyotype consisted of 10 metacentric, 26 submetacentric and 14 subtelocentric elements, with a fundamental number FN=86 (Fig. 2a). The larger metacentric pair (number 1), is about 2/3 longer than the average length of the rest of the metacentric series. No differences between chromosome complements were found.

Bottom Line: The first metacentric pair presents two well-defined heterochromatic blocks in paracentromeric position, near the centromere.Impregnation with silver nitrate showed a single pair of Ag-positive NORs localized at terminal regions of the short arms of the subtelocentric chromosome pair number 12.Comparison of results here reported with those available on other Characidae permit to hypothesize that the presence of a very large metacentric pair might represent a unique and derived condition that characterize one of four major lineages molecularly identified in this family.

View Article: PubMed Central - PubMed

Affiliation: Universidad Técnica de Machala, El Oro, Ecuador ; Universidad Nacional Mayor de San Marcos UNMSM, Lima, Perú

ABSTRACT
Karyotypic features of Rhoadsiaaltipinna Fowler, 1911 from Ecuador were investigated by examining metaphase chromosomes through Giemsa staining, C-banding, Ag-NOR, and two-color-fluorescence in situ hybridization (FISH) for mapping of 18S and 5S ribosomal genes. The species exhibit a karyotype with 2n = 50, composed of 10 metacentric, 26 submetacentric and 14 subtelocentric elements, with a fundamental number FN=86 and is characterized by the presence of a larger metacentric pair (number 1), which is about 2/3 longer than the average length of the rest of the metacentric series. Sex chromosomes were not observed. Heterochromatin is identifiable on 44 chromosomes, distributed in paracentromeric position near the centromere. The first metacentric pair presents two well-defined heterochromatic blocks in paracentromeric position, near the centromere. Impregnation with silver nitrate showed a single pair of Ag-positive NORs localized at terminal regions of the short arms of the subtelocentric chromosome pair number 12. FISH assay confirmed these localization of NORs and revealed that minor rDNA clusters occur interstitially on the larger metacentric pair number 1. Comparison of results here reported with those available on other Characidae permit to hypothesize that the presence of a very large metacentric pair might represent a unique and derived condition that characterize one of four major lineages molecularly identified in this family.

No MeSH data available.


Related in: MedlinePlus