The karyotypes of the thorny catfishes Wertheimeria maculata Steindachner, 1877 and Hassar wilderi Kindle, 1895 (Siluriformes: Doradidae) and their relevance in doradids chromosomal evolution

• Autor(a) principal: Dergam, Jorge A.
• Data de Publicação: 2006
• Outros Autores: Eler, Eduardo S., Vênere, Paulo C., Paiva, Lı́lian C., Miranda, Gabriela A., Oliveira, Alessandro A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://dx.doi.org/10.1007/s10709-006-0023-4; http://www.locus.ufv.br/handle/123456789/22345
• topic: Brazilian coastal basins; Conservation genetics; Cytotaxonomy; South American biodiversity

We studied the karyotypes of two doradids, the rare and endangered Wertheimeria maculata and a derived Amazonian species, Hassar wilderi. Cytogenetic characterization was assessed using conventional staining (Giemsa), C-banding, and NOR banding. Both species had 2n = 58 chromosomes but differed in their chromosome formulae, 24 m + 14sm + 8st + 12a for W. maculata and 32 m + 16sm + 10st for H. wilderi. In W. maculata heterochromatin was mainly telomeric, and three chromosomes had a fully heterochromatic arm; in H. wilderi heterochromatin was also predominantly telomeric and evident in many more chromosomes. Hassar wilderi also presented one pair of homologues with a fully heterochromatic arm. In both species, nucleolar organizer regions were restricted to one pair of subtelocentric chromosomes. Assuming a basal position for W. maculata, we hypothesized that underlying conserved diploid and NOR-bearing chromosome numbers, chromosomal evolution in doradids has involved pericentric inversions and an increase of heterochromatic blocks.