Use este identificador para citar ou linkar para este item: https://repositorio.inpa.gov.br/handle/1/17830
Título: XX/XO, a rare sex chromosome system in Potamotrygon freshwater stingray from the Amazon Basin, Brazil
Autor: Valentim, Francisco Carlos Souza de
Porto, Jorge Ivan Rebelo
Bertollo, Luiz Antônio Carlos
Gross, Maria Claudia
Feldberg, Eliana
Palavras-chave: Animals
Centromere
Female
Genetics
Karyotype
Male
Review
Sexual Development
Skates (fish)
X Chromosome
Animal
Centromere
Female
Karyotype
Male
Sex Characteristics
Skates (fish)
X Chromosome
Data do documento: 2013
Revista: Genetica
É parte de: Volume 141, Número 7-9, Pags. 381-387
Abstract: Potamotrygonidae is a representative family of South American freshwater elasmobranchs. Cytogenetic studies were performed in a Potamotrygon species from the middle Negro River, Amazonas, Brazil, here named as Potamotrygon sp. C. Mitotic and meiotic chromosomes were analyzed using conventional staining techniques, C-banding, and detection of the nucleolus organizing regions (NOR) with Silver nitrate (Ag-NOR). The diploid number was distinct between sexes, with males having 2n = 67 chromosomes, karyotype formula 19m + 8sm + 10st + 30a, and fundamental number (FN) = 104, and females having 2n = 68 chromosomes, karyotype formula 20m + 8sm + 10st + 30a, and FN = 106. A large chromosome, corresponding to pair number two in the female karyotype, was missing in the male complement. Male meiotic cells had 33 bivalents plus a large univalent chromosome in metaphase I, and n = 33 and n = 34 chromosomes in metaphase II. These characteristics are consistent with a sex chromosome system of the XX/XO type. Several Ag-NOR sites were identified in both male and female karyotypes. Positive C-banding was located only in the centromeric regions of the chromosomes. This sex chromosome system, which rarely occurs in fish, is now being described for the first time among the freshwater rays of the Amazon basin. © 2013 Springer Science+Business Media Dordrecht.
DOI: 10.1007/s10709-013-9737-2
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