Chromosome Studies in Hypoptopomatinae (Pisces, Siluriformes, Loricariidae): L. XX/XY Sex Chromosome Heteromorphism in Pseudotocinclus tietensis
The cytogenetic analysis of 13 specimens (9 males and 4 females) of Pseudotocinclus tietensis showed that this species has 2n=54 chromosomes (26M+20SM+6ST) plus one heteromorphic pair (SM/M) in the males and one homomorphic pair (SM/SM) in the females. Ag-NORs are located interstitially on the long...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1992 |
| País: | Brasil |
| Institución: | Universidade Estadual Paulista (UNESP) |
| Repositorio: | Repositório Institucional da UNESP |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.unesp.br:11449/230704 |
| Acceso en línea: | http://dx.doi.org/10.1508/cytologia.57.369 http://hdl.handle.net/11449/230704 |
| Access Level: | acceso abierto |
| Palabra clave: | C-band Karyotype NOR Pseudotocinclus XX/XY sex chromosomes |
| Sumario: | The cytogenetic analysis of 13 specimens (9 males and 4 females) of Pseudotocinclus tietensis showed that this species has 2n=54 chromosomes (26M+20SM+6ST) plus one heteromorphic pair (SM/M) in the males and one homomorphic pair (SM/SM) in the females. Ag-NORs are located interstitially on the long arm of the largest metacentric pair and a small amount of constitutive heterochromatin is present in the karyotypes. The occurrence of a heteromorphic pair in the males is demonstrable by the presence of one extra C-banded block in the Y chromosome. The presence of one heterochromatin block distinguishing the sexual chromosomes suggests that this species presents a very primitive mechanism of sex chromosome differentiation. © 1992, Japan Mendel Society, International Society of Cytology. All rights reserved. |
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