Microstructural chromosome reorganization in the genus Trichomycterus (Siluriformes: Trichomycteridae)

Trichomycterus is a specious fish genus within Trichomycterinae and displays remarkable karyotype diversity. However, knowledge about their genomic structure and location of repetitive sequence is still limited. In order to better understand the karyotype diversification, we analyzed nine species of...

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Bibliographic Details
Authors: Oliveira, Maria Ligia M. de [UNESP], Utsunomia, Ricardo [UNESP], Pansonato-Alves, Jose Carlos [UNESP], Scacchetti, Priscilla C. [UNESP], Primo, Cleberson C., Vicari, Marcelo R., Artoni, Roberto F., Centofante, Liano, Moreira-Filho, Orlando, Oliveira, Claudio [UNESP], Foresti, Fausto [UNESP]
Format: article
Status:Published version
Publication Date:2016
Country:Brasil
Institution:Universidade Estadual Paulista (UNESP)
Repository:Repositório Institucional da UNESP
Language:English
OAI Identifier:oai:repositorio.unesp.br:11449/161788
Online Access:http://dx.doi.org/10.1590/1982-0224-20150084
http://hdl.handle.net/11449/161788
Access Level:Open access
Keyword:Karyotype diversity
Repetitive DNA
rDNA
Supernumerary chromosomes
Description
Summary:Trichomycterus is a specious fish genus within Trichomycterinae and displays remarkable karyotype diversity. However, knowledge about their genomic structure and location of repetitive sequence is still limited. In order to better understand the karyotype diversification, we analyzed nine species of Trichomycterus using classical and molecular cytogenetic techniques. Results revealed a conserved diploid chromosome number of 2n=54 chromosomes in all analyzed species, although remarkable differences on the constitutive heterochromatin distribution were observed. In addition, while the 18S rDNA showed a conserved distribution pattern, the 5S rDNA sites showed a quite diverse location considering the analyzed species. Remarkably, both ribosomal genes were co-located in all species, except in T. iheringi, suggesting that co-localization is probably an ancestral condition in Trichomycterus. Finally, three analyzed species showed heterochromatic B chromosomes, reinforcing the intense genomic reorganization occurring in Trichomycterus. Our results showed that chromosomal variations are not restricted to differences in karyotype formula as previously proposed, but also to modifications on the microstructural level of resolution.

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