Artículos de revistas
Chromosome analysis in saccodon wagneri (Characiformes) and insights into the karyotype evolution of parodontidae
Fecha
2021-01-01Registro en:
Neotropical Ichthyology, v. 19, n. 1, p. 1-13, 2021.
1982-0224
1679-6225
10.1590/1982-0224-2020-0103
S1679-62252021000100203
2-s2.0-85102419751
S1679-62252021000100203.pdf
Autor
Universidad Técnica de Machala
Universidad de Oriente
Universidade Estadual Paulista (Unesp)
Universidade Federal de São Carlos (UFSCar)
Escuela Politécnica Nacional
Sapienza-Università di Roma
Institución
Resumen
Parodontidae is a relatively small group of Neotropical characiform fishes consisting of three genera (Apareiodon, Parodon, and Saccodon) with 32 valid species. A vast cytogenetic literature is available on Apareiodon and Parodon, but to date, there is no cytogenetic data about Saccodon, a genus that contains only three species with a trans-Andean distribution. In the present study the karyotype of S. wagneri was described, based on both conventional (Giemsa staining, Ag-NOR, C-bands) and molecular (repetitive DNA mapping by fluorescent in situ hybridization) methods. A diploid chromosome number of 2n = 54 was observed in both sexes, and the presence of heteromorphic sex chromosomes of the ZZ/ ZW type was detected. The W chromosome has a terminal heterochromatin band that occupies approximately half of the long arm, being this band approximately half the size of the Z chromosome. The FISH assay showed a synteny of the 18S-rDNA and 5S-rDNA genes in the chromosome pair 14, and the absence of interstitial telomeric sites. Our data reinforce the hypothesis of a conservative karyotype structure in Parodontidae and suggest an ancient origin of the sex chromosomes in the fishes of this family.