Chromosomal polymorphism in Steindachneridion melanodermatum Garavello, 2005 (Siluriformes, Pimelodidae): a reappraisal the existence of sex chromosome system in the species

Abstract

Fifty-five specimens of Steindachneridion melanodermatum were analyzed using molecular and conventional cytogenetic tools. Two polymorphisms were found: one involving the length of nucleolar organizer regions and another involving two submetacentric chromosomes previously identified as sex chromosomes. The polymorphism was confirmed by homogeneity between male and female karyotypes. Nucleotide sequencing and physical chromosome mapping were also used to identify and characterize one class of repetitive DNA, named SmAluI-Rex3. Based on the results and literature the present study offers an update of the occurrence of sex chromosome system in this species.

Chromosome mapping of retrotransposable elementsRex1andRex3inLeporinusSpix, 1829 species (Characiformes: Anostomidae) and its relationships among heterochromatic segments and W sex chromosome

“…20 In the present study, the Leporinus species had different hybridization signals with dispersed clusters and signals in the terminal regions. These patterns were similar to those observed in the Bryconinae, 35 Erythrinidae, 36 Sternopygidae, 37 Artedidraconidae, 18 Bathydraconidae, 18 Bovichtidae, 18 Channichthyidae, 18 Nototheniidae, 18 Loricariidae, 19 Pimelodidae, 38 and Tetraodontidae. 17 Species in the family Cichlidae are exceptional because the Rex elements are frequently distributed in the pericentromeric regions.…”

The Bunocephalus coracoideus Species Complex (Siluriformes, Aspredinidae). Signs of a Speciation Process through Chromosomal, Genetic and Ecological Diversity

“…Cytogenetic studies, including the molecular organization and cytogenetic mapping of repetitive DNAs might be a significant data set for the characterization of particular segments of biota, providing important information for phylogenomics ( Cioffi et al, 2012 ). Besides, these sequences seem to escape the selective pressure that acts in the non-repetitive segments, thus representing good evolutionary markers to detect recent events of evolution, once the number and location of these sequences may reveal polymorphisms, with intra- and inter-specific variations due to rearrangements, even in conserved karyotypes ( Cioffi et al, 2009 ; Matoso et al, 2011 ; Motta-Neto et al, 2012 ; Oliveira et al, 2015 ). Up to now, only two Bunocephalus species had cytogenetic studies already conducted, B. doriae and B. coracoideus .…”

Chromosomal diversification in ribosomal DNA sites in Ancistrus Kner, 1854 (Loricariidae, Ancistrini) from three hydrographic basins of Mato Grosso, Brazil

“…Studies that characterize the chromosomal locations of 5S and 18S rDNA in Siluriformes are scarce ( Kavalco et al 2004 ; Centofante et al 2006 ; Mendes-Neto et al 2011). A few such studies were conducted in Pimelodidade and Pseudopimelodidae , where non-syntenic 5S and 18S ribosomal regions were observed ( Carvalho and Dias 2007 ; Garcia and Moreira-Filho 2008 ; Marques et al 2008 ; Matoso et al 2011 ; Moraes Neto et al 2011 ; Silva et al 2011 ). In Loricariidae , chromosomes with syntenic 5S and 18S regions were observed in some groups like Neoplecostominae and the out group Trichomycteridae ( Ziemniczak 2011 ).…”