Three sympatric karyomorphs in the fish Astyanax fasciatus (Teleostei, Characidae) do not seem to hybridize in natural populations

Ferreira-Neto, Maressa [UNESP]; Artoni, Roberto Ferreira; Vicari, Marcelo Ricardo; Moreira-Filho, Orlando; Martinez Camacho, Juan Pedro; Bakkali, Mohammed; de Oliveira, Claudio [UNESP]; Foresti, Fausto [UNESP]

Three sympatric karyomorphs in the fish Astyanax fasciatus (Teleostei, Characidae) do not seem to hybridize in natural populations

Arquivos

WOS000303289800003.pdf (2.35 MB)

Data

2012-01-01

Autores

Ferreira-Neto, Maressa

Artoni, Roberto Ferreira

Vicari, Marcelo Ricardo

Moreira-Filho, Orlando

Martinez Camacho, Juan Pedro

Bakkali, Mohammed

de Oliveira, Claudio

Foresti, Fausto

Editor

Zoological Inst

Tipo

Artigo

Direito de acesso

Acesso aberto

Resumo

Ninety individuals of the characid fish Astyanax fasciatus (Cuvier, 1819) were collected at Agua da Madalena stream (Botucatu, São Paulo, Brazil) and analyzed for diploid chromosome number 2n and karyotype composition as well as for the chromosomal location of the 5S and 18S ribosomal DNA (rDNA). Whereas no chromosome differences were associated with sex, three different karyomorphs with diploid chromosome numbers 2n=46, 2n=48 and 2n=50 were found. No intermediate 2n numbers were discovered. The 2n=50 karyomorph showed some differences in 18S rDNA location compared to the two other karyomorphs. Finally, all specimens with the 2n=46 karyomorph showed the presence of a partly heterochromatic macro supernumerary chromosome, which was absent in all individuals with the two other karyomorphs. All these results suggest that indviduals of the three different karyomorphs are not likely to hybridize in the examined populations. Our findings strongly suggest the presence of three separate species (sensu biological species concept) easily diagnosed on the basis of differences in the diploid chromosome numbers and other chromosomal markers.