Data/hora: 02/06/2024 02:10:28

Provedor de dados: 	83	
País: 	Brazil	
Título: 	First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)	
Autores: 	Fernandes,Carlos Alexandre; Aguiar,Allan Kardec Moreira de; Paiz,Leonardo Marcel; Baumgärtner,Lucas; Piscor,Diovani; Margarido,Vladimir Pavan.	
Data: 	2019-01-01	
Ano: 	2019	
Palavras-chave: 	Ag-NORs; C-banding; Fish cytogenetics; Karyotype evolution; Repetitive sequences.	
Resumo: 	ABSTRACT Gymnorhamphichthys britskii is a Neotropical electric fish of family Rhamphichthyidae described from the Paraná-Paraguay system. This study reports the first karyotypic description of G. britskii collected from the upper Paraná river basin, which presented 2n=38 chromosomes, karyotype composed of 14 metacentric, 8 submetacentric, 2 subtelocentric and 14 acrocentric chromosomes, and fundamental number as 62 for both sexes. Heteromorphic sex chromosomes were absent. A single pair of nucleolar organizing regions (NORs) was detected in the submetacentric chromosome pair number 9 by silver staining and confirmed by the 18S rDNA probe. The 5S rDNA was located in a single chromosome pair. Heterochromatic regions were clearly observed in the short arms of the NOR-bearing chromosome pair and in the telomeric positions of most acrocentric chromosomes. Besides the present data are valuable to help in understanding karyotypic evolution in Rhamphichthyidae, data from NORs confirmed the tendency of this family in presenting simple NORs sites, similar to the other Gymnotiformes clades. Yet, the presence of a large heterochromatic block in the NOR-bearing chromosome can be used as cytogenetic markers for G. britskii, and that centric fusions appear to be an important mechanism in the karyotype evolution and differentiation among Gymnotiformes species.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000300205	
Editor: 	Sociedade Brasileira de Ictiologia	
Relação: 	10.1590/1982-0224-20190069	
Formato: 	text/html	
Fonte: 	Neotropical Ichthyology  v.17 n.3 2019	
Fonte: 	info:eu-repo/semantics/openAccess