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Cytogenetic characterization of F1, F2 and backcross hybrids of the Neotropical catfish species Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Pimelodidae, Siluriformes).

do Prado FD, Nunes TL, Senhorini JA, Bortolozzi J, Foresti F, Porto-Foresti F - Genet. Mol. Biol. (2012)

Bottom Line: The diploid number of 56 chromosomes was constant in all species and lineages, with a karyotypic formula containing 20 metacentric, 12 submetacentric, 12 subtelocentric and 12 acrocentric chromosomes.Nucleolar organizer regions (NORs) were identified in two subtelocentric chromosomes in the parents and hybrids, with partial nucleolar dominance in F1 and F2 specimens.Heterochromatic blocks were detected in the terminal and centromeric regions of some chromosomes in all individuals.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista "Júlio de Mesquita Filho", Bauru, SP, Brazil.

ABSTRACT
The cytogenetic characteristics of Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum and their F1, F2 and backcross hybrids were assessed by using chromosome banding techniques. The diploid number of 56 chromosomes was constant in all species and lineages, with a karyotypic formula containing 20 metacentric, 12 submetacentric, 12 subtelocentric and 12 acrocentric chromosomes. Nucleolar organizer regions (NORs) were identified in two subtelocentric chromosomes in the parents and hybrids, with partial nucleolar dominance in F1 and F2 specimens. Heterochromatic blocks were detected in the terminal and centromeric regions of some chromosomes in all individuals. For parental and hybrid lineages, 18S ribosomal clusters corresponding to NORs and 5S ribosomal genes were identified in distinct pairs of chromosomes. The striking conservation in the chromosomal macrostructure of the parental species may account for the fertility of their F1 hybrids. Similarly, the lack of marked alterations in the chromosomal structure of the F1 hybrids could account for the maintenance of these features in post-F1 lineages.

No MeSH data available.


Karyotypes of the F1 hybrids “pintachara” (A,B) and “cachapinta” (C,D) after Giemsa staining (A,C) and C-banding (B,D). The chromosomes bearing NORs are shown in detail (boxes). Bars indicate the karyotype localization of the NOR-bearing chromosomes. Scale bar = 10 μm.
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f2-gmb-35-1-57: Karyotypes of the F1 hybrids “pintachara” (A,B) and “cachapinta” (C,D) after Giemsa staining (A,C) and C-banding (B,D). The chromosomes bearing NORs are shown in detail (boxes). Bars indicate the karyotype localization of the NOR-bearing chromosomes. Scale bar = 10 μm.

Mentions: All of the samples of P. corruscans and P. reticulatum analyzed, i.e., the parental lineages (Figure 1), F1 hybrids (“cachapinta” and “pintachara”) (Figure 2), and F2 hybrids and backcrosses (Figure 3), had a diploid number of 56 chromosomes arranged in a karyotype containing 20m+12sm+12st+12a, with no evidence of sex-related chromosomal heteromorphism. C-banding revealed heterochromatic markings in the pericentromeric and terminal portions of some chromosomes in both of the parental and all of the hybrid lineages (Figures 1B,D, 2B,D and 3B,D, respectively).


Cytogenetic characterization of F1, F2 and backcross hybrids of the Neotropical catfish species Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Pimelodidae, Siluriformes).

do Prado FD, Nunes TL, Senhorini JA, Bortolozzi J, Foresti F, Porto-Foresti F - Genet. Mol. Biol. (2012)

Karyotypes of the F1 hybrids “pintachara” (A,B) and “cachapinta” (C,D) after Giemsa staining (A,C) and C-banding (B,D). The chromosomes bearing NORs are shown in detail (boxes). Bars indicate the karyotype localization of the NOR-bearing chromosomes. Scale bar = 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3313517&req=5

f2-gmb-35-1-57: Karyotypes of the F1 hybrids “pintachara” (A,B) and “cachapinta” (C,D) after Giemsa staining (A,C) and C-banding (B,D). The chromosomes bearing NORs are shown in detail (boxes). Bars indicate the karyotype localization of the NOR-bearing chromosomes. Scale bar = 10 μm.
Mentions: All of the samples of P. corruscans and P. reticulatum analyzed, i.e., the parental lineages (Figure 1), F1 hybrids (“cachapinta” and “pintachara”) (Figure 2), and F2 hybrids and backcrosses (Figure 3), had a diploid number of 56 chromosomes arranged in a karyotype containing 20m+12sm+12st+12a, with no evidence of sex-related chromosomal heteromorphism. C-banding revealed heterochromatic markings in the pericentromeric and terminal portions of some chromosomes in both of the parental and all of the hybrid lineages (Figures 1B,D, 2B,D and 3B,D, respectively).

Bottom Line: The diploid number of 56 chromosomes was constant in all species and lineages, with a karyotypic formula containing 20 metacentric, 12 submetacentric, 12 subtelocentric and 12 acrocentric chromosomes.Nucleolar organizer regions (NORs) were identified in two subtelocentric chromosomes in the parents and hybrids, with partial nucleolar dominance in F1 and F2 specimens.Heterochromatic blocks were detected in the terminal and centromeric regions of some chromosomes in all individuals.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista "Júlio de Mesquita Filho", Bauru, SP, Brazil.

ABSTRACT
The cytogenetic characteristics of Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum and their F1, F2 and backcross hybrids were assessed by using chromosome banding techniques. The diploid number of 56 chromosomes was constant in all species and lineages, with a karyotypic formula containing 20 metacentric, 12 submetacentric, 12 subtelocentric and 12 acrocentric chromosomes. Nucleolar organizer regions (NORs) were identified in two subtelocentric chromosomes in the parents and hybrids, with partial nucleolar dominance in F1 and F2 specimens. Heterochromatic blocks were detected in the terminal and centromeric regions of some chromosomes in all individuals. For parental and hybrid lineages, 18S ribosomal clusters corresponding to NORs and 5S ribosomal genes were identified in distinct pairs of chromosomes. The striking conservation in the chromosomal macrostructure of the parental species may account for the fertility of their F1 hybrids. Similarly, the lack of marked alterations in the chromosomal structure of the F1 hybrids could account for the maintenance of these features in post-F1 lineages.

No MeSH data available.