The family Cichlidae is considered a non-Ostariophysi freshwater fish family with diverse and geographical distribution wide in the world; nevertheless there is scarce cytogenetic information for the group. Accordingly, we aim to characterize Cichla kelberi and Cichla piquiti specimens by conventional cytogenetic (Giemsa, Ag-NOR, Banding C) and cyto-molecular (FISH with 5S, 18S, Rag1, Rex3, Rex6 and telomeric probes) markers. In both species, cytogenetic analyses showed 2n=48 chromosomes (all of the subtelocentric/acrocentric type), NORs located terminally on the second chromosome pair and heterochromatic blocks in the centromeres of some chromosomes. The location of the 18S ribosomal gene confirms what was previously observed with impregnation with silver nitrate, while the 5S rDNA is in interstitial position on the third chromosome pair. The telomeric probe, as expected, was present only in telomeric regions of all chromosomes. The Rag1, transposable elements, Rex3 and Rex6 present dispersed sites throughout most of the chromosomes, not characterizing a definite pattern of distribution. Thus, the present study adds relevant information about the cytogenetics and behavior of different repetitive DNA families in C. kelberi and C. piquiti, which require future studies to understand the gene behavior and evolution in Neotropical fish, especially in the genus Cichla.
This study reports a case of occurrence of hybrid fish in the Amazon River basin, Brazil and attentive on to possible risks promoted with from crossbreeding between two species on local biodiversity. The specimen was collected in February/2016, and was evaluated showing dubious characteristics indicating the possibility of the occurrence of hybridization. Thus, fin specimen fragments were sampled and the genetic analyzes were performed. Our results indicated that the studied sample had a heterozygous electrophoretic profile revealing itself as a hybrid between Piaractus brachypomus and Colossoma macropomum being the second species the maternal parent.
This study reports the first cytogenetic characterization of the Amazonian catfish Leiarius marmoratus (“jandiá”) and its F1 (first generation) 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, similar to the previously described for P. reticulatum. The data suggested that the hybrid karyotype might be insufficient for a precise discrimination of hybrids, however, Ag-NOR can be used as a chromosome marker to differentiate “cachandiá” from L. marmoratus and P. reticulatum. The current study also provides insights into the chromosomal features of L. marmoratus and contributes with novel cytogenetic information of this native Amazonian catfish included in the Pimelodidae family.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.