Sex chromosome evolution in fish: the formation of the neo-Y chromosome in Eigenmannia (Gymnotiformes)
Nenhuma Miniatura disponível
Data
2000-01-01
Autores
Almeida-Toledo, L. F.
Foresti, F.
Daniel, MFZ
Toledo, S. A.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Springer
Resumo
Chromosomes of a species of Eigenmannia presenting a X1X1X2X2:X1X2Y sex chromosome system, resulting from a Y-autosome Robertsonian translocation, were analyzed using the C-banding technique, chromomycin A(3) (CMA(3)) and mithramycin (MM) staining and in situ digestion by the restriction endonuclease AluI. A comparison of the metacentric Y chromosome of males with the corresponding acrocentrics in females indicated that a C-band-positive, CMA(3)/MM-fluorescent and AluI digestion-resistant region had been lost during the process of translocation, resulting in a diminution of heterochromatin in the males. It is hypothesized that the presence of a smaller amount of G+C-rich heterochromatin in the sex chromosomes of the heteromorphic sex when compared with the homomorphic sex may be associated with the sex determination mechanism in this species and may be a more widely occurring phenomenon in fish with differentiated sex chromosomes than was initially thought.
Descrição
Palavras-chave
Como citar
Chromosoma. New York: Springer Verlag, v. 109, n. 3, p. 197-200, 2000.