title: Basic cytogenetics and physical mapping of 5S and 18S ribosomal genes in Hoplias malabaricus (Osteichthyes, Characiformes, Erythrinidae) from isolated natural lagoons: a conserved karyomorph along the Iguaçu river basin.
abstract: Erythrinidae include Neotropical teleost fish that are widely distributed in South America. Hoplias Gill, 1903 include two large groups: H. malabaricus Bloch, 1794 and H. lacerdae Miranda Ribeiro, 1908. Hoplias malabaricus is characterized by remarkable karyotype diversity, with some karyomorphs widely distributed geographically while others are more restricted to certain river basins. Cytogenetic analyzes were performed in a population of Hoplias malabaricus from the Wildlife Refuge of Campos de Palmas, the Iguaçu River basin. The specimens showed diploid number of 42 chromosomes (24m+18sm) without differentiated sex chromosomes system. The impregnation by silver nitrate showed multiple AgNORs. Seven pairs (4, 7, 10, 13, 16, 20 and 21) carrying 18S rDNA were detected by FISH. Heterochromatin was verified in the centromeric and pericentromeric region of most chromosomes and the terminal region of some pairs. FISH with 5S rDNA probes showed two chromosome pairs carrying these sites in the interstitial region (8 and 14). The data obtained in this study are similar to those found for two other populations of H. malabaricus already studied in the basin of the Iguaçu River, confirming the hypothesis that this species is natural, not having been introduced, as well as having an intrinsic characteristic, such as the largest number of sites of 18S rDNA.
authors.affiliation: Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Rua Universitária 2069, CEP: 85819-110, Cascavel, PR, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Gemi
authors.affiliation: Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Rua Universitária 2069, CEP: 85819-110, Cascavel, PR, Brazil.
authors.forename: Roberto Laridondo
authors.initials: RL
authors.lastname: Lui
authors.affiliation: Universidade Paranaense, Avenida Julio Assis Cavalheiro 2000, CEP: 85601-000, Francisco Beltrão, PR, Brazil.
authors.forename: Fernando Rodrigo
authors.initials: FR
authors.lastname: Treco
authors.affiliation: Universidade Estadual de Maringá, Departamento de Biologia, CEP: 87020-900 Maringá, PR, Brazil.
authors.forename: Leonardo Marcel
authors.initials: LM
authors.lastname: Paiz
authors.affiliation: Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Rua Universitária 2069, CEP: 85819-110, Cascavel, PR, Brazil.
authors.forename: Rafaela Maria
authors.initials: RM
authors.lastname: Moresco
authors.affiliation: Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Rua Universitária 2069, CEP: 85819-110, Cascavel, PR, Brazil.
authors.forename: Vladimir Pavan
authors.initials: VP
authors.lastname: Margarido
keywords: Chromosomal conservadorism; double-FISH; evolution; karyotype; rDNA