Karyotypic conservatism in samples of Characidium cf. zebra (Teleostei, Characiformes, Crenuchidae): physical mapping of ribosomal genes and natural triploidy

Basic and molecular cytogenetic analyses were performed in specimens of Characidium cf. zebra from five collection sites located throughout the Tietê, Paranapanema and Paraguay river basins. The diploid number in specimens from all samples was 2n = 50 with a karyotype composed of 32 metacentric and 18 submetacentric chromosomes in both males and females. Constitutive heterochromatin was present at the centromeric regions of all chromosomes and pair 23, had additional interstitial heterochromatic blocks on its long arms. The nucleolar organizer regions (NORs) were located on the long arms of pair 23, while the 5S rDNA sites were detected in different chromosomes among the studied samples. One specimen from the Alambari river was a natural triploid and had two extra chromosomes, resulting in 2n = 77. The remarkable karyotypic similarity among the specimens of C. cf. zebra suggests a close evolutionary relationship. on the other hand, the distinct patterns of 5S rDNA distribution may be the result of gene flow constraints during their evolutionary history.

Cytogenetic Mapping of rRNAs and Histone H3 Genes in 14 Species of Dichotomius ( Coleoptera, Scarabaeidae, Scarabaeinae) Beetles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosome Mapping of Retrotransposable Elements Rex1 and Rex3 in Three Fish Species in the Subfamily Hypoptopomatinae (Teleostei, Siluriformes, Loricariidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

5S rDNA chromosomal mapping and COI sequence analysis reveal differentiation among distinct populations of a characid fish Serrapinnus notomelas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosome Evolution in African Cichlid Fish: Contributions from the Physical Mapping of Repeated DNAs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosome Mapping of H1 Histone and 5S rRNA Gene Clusters in Three Species of Astyanax (Teleostei, Characiformes)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosomal Variability among Allopatric Populations of Erythrinidae Fish Hoplias malabaricus: Mapping of Three Classes of Repetitive DNAs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular Characterization and Physical Mapping of Two Classes of 5S rDNA in the Genomes of Gymnotus sylvius and G. inaequilabiatus (Gymnotiformes, Gymnotidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Physical chromosome mapping of repetitive DNA sequences in Nile tilapia Oreochromis niloticus: Evidences for a differential distribution of repetitive elements in the sex chromosomes

Repetitive DNAs have been extensively applied as physical chromosome markers on comparative studies, identification of chromosome rearrangements and sex chromosomes, chromosome evolution analysis, and applied genetics. Here we report the characterization of repetitive DNA sequences from the Nile tilapia (Oreochromis niloticus) genome by construction and screening of plasmid library enriched with repetitive DNAs, analysis of a BAC-based physical map, and hybridization to chromosomes. The physical mapping of BACs enriched with repetitive sequences and C(o)t-1 DNA (DNA enriched for highly and moderately repetitive DNA sequences) to chromosomes using FISH showed a predominant distribution of repetitive elements in the centromeric and telomeric regions and along the entire length of the largest chromosome pair (X and Y sex chromosomes) of the species. The distribution of repetitive DNAs differed significantly between the p arm of X and Y chromosomes. These findings suggest that repetitive DNAs have had an important role in the differentiation of sex chromosomes. (c) 2007 Elsevier Ltd. All rights reserved.

Cytogenetic Mapping of the Retroelements Rex1, Rex3 and Rex6 among Cichlid Fish: New Insights on the Chromosomal Distribution of Transposable Elements

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cytogenetic Mapping of 5S and 18S rRNAs and H3 Histone Genes in 4 Ancient Proscopiidae Grasshopper Species: Contribution to Understanding the Evolutionary Dynamics of Multigene Families

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative cytogenetic mapping of Sox2 and Sox14 in cichlid fishes and inferences on the genomic organization of both genes in vertebrates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative chromosome mapping of repetitive sequences. Implications for genomic evolution in the fish, Hoplias malabaricus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)