title: Chromosomal Mapping of Repetitive Sequences (Rex3, Rex6, and rDNA Genes) in Hybrids Between Colossoma macropomum (Cuvier, 1818) and Piaractus mesopotamicus (Holmberg, 1887).
abstract: Some species of Characiformes are known for their high economic value, such as Colossoma macropomum and Piaractus mesopotamicus, and are used in aquaculture programs to generate hybrid tambacu (interbreeding of C. macropomum females and P. mesopotamicus males). The present work aimed to investigate the location of the Rex3 and Rex6 transposable elements in the hybrid and in the species, in addition to checking the genomic organization of the 18S and 5S rDNA in tambacu. The diploid number found for the hybrid was equal to 54 chromosomes, with heterochromatic blocks distributed mainly in the centromeric portions. The chromosomal location of the mobile elements Rex3 and Rex6 in C. macropomum, P. mesopotamicus, and in the hybrid between these species enabled knowledge expansion and the generation of data on such mobile elements. In addition, the location of such elements is not related to the distribution of ribosomal DNA sites. The mapping of the 18S rDNA was shown to be effective in cytogenetic identification of the hybrid tambacu, allowing for differentiation from the parent species and from the hybrid between C. macropomum and the other species from Piaractus (P. brachypomus).
authors.affiliation: 1 Centro de Ciências da Saúde, Universidade Federal de Roraima (UFRR) , Boa Vista, Brazil .
authors.forename: Leila Braga
authors.initials: LB
authors.lastname: Ribeiro
authors.affiliation: 2 Programa de Pós-Graduação em Ciência Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso do Sul (UFMS) , Campo Grande, Brazil .
authors.forename: Americo
authors.initials: A
authors.lastname: Moraes Neto
authors.affiliation: 3 Programa de Pós-Graduação em Biologia Evolutiva, Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa (UEPG) , Ponta Grossa, Brazil .
authors.forename: Roberto Ferreira
authors.initials: RF
authors.lastname: Artoni
authors.affiliation: 4 Departamento de genética, Universidade Federal do Amazonas (UFAM) , Manaus, Brazil .
authors.forename: Daniele Aparecida
authors.initials: DA
authors.lastname: Matoso
authors.affiliation: 5 Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA) , Manaus, Brazil .
authors.forename: Eliana
authors.initials: E
authors.lastname: Feldberg
mesh_terms: D000818:Animals; D060125:Characiformes / Q000235:genetics*; D002874:Chromosome Mapping; D004275:DNA, Ribosomal / Q000235:genetics*; D005260:Female; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006824:Hybridization, Genetic / Q000235:genetics*; D059785:Karyotype; D008297:Male; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*
chemical_list: D004275:DNA, Ribosomal; D029941:Fish Proteins
keywords: Colossoma macropomum; mobile elements; rDNA genes heterocromatin; tambacu