First Cytogenetic Characterization of the Amazon Catfish Leiarius marmoratus (Gill, 1870) and Its Hybrid with Pseudoplatystoma reticulatum (Eigenmann & Eigenmann, 1889)

Autor: Fernanda Dotti do Prado, Fabio Porto-Foresti, Andrea Abrigato de Freitas Mourão, Fausto Foresti, José Augusto Senhorini
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Caryologia (2021)
Druh dokumentu: article
ISSN: 0008-7114
2165-5391
DOI: 10.36253/caryologia-1149
Popis: This study reports the first cytogenetic characterization of the Amazonian catfish Leiarius marmoratus (“jandiá”) and its F1 (first generation or interspecific) hybrid “cachandiá” with Pseudoplatystoma reticulatum (“cachara”). A diploid number of 56 chromosomes and a single argyrophilic nucleolus organizer region (Ag-NOR) in the short arm of two sub-telocentric chromosomes were observed for both L. marmoratus and P. reticulatum, but with differences in the karyotype formula and the size of the chromosome pair with NORs. The hybrid showed 2n = 56 chromosomes with an intermediate karyotype when compared to the parental species. A single Ag-NOR was maintained in the hybrid but located in two chromosomes with marked differences in size and presenting intraindividual variation in NOR activity (nucleolar dominance). For L. marmoratus and the hybrid, heterochromatic bands were predominately distributed in the terminal, centromeric, and sub-centromeric regions of some chromosomes and 5S rDNA sites located in two distinct sub-telocentric chromosomes, which was the same pattern than previously described for P. reticulatum in other studies. These results corroborated the lack of hybrid chromosomal homology, with chromosomes originating from L. marmoratus and from P. reticulatum. Results showed that chromosome morphology might be insufficient to account for a clear discrimination of hybrids from the parental lineages, however, Ag-NOR can help for the identification of hybrid fishes. The current study provides insights into the chromosomal features of L. marmoratus, and its hybrid, and contributes novel information about the rich biodiversity of fishes in South America.
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