Chromosomal mapping of the major and minor ribosomal genes, (GATA)n and U2 snRNA gene by double-colour FISH in species of the Batrachoididae family

Abstract

In the present study dual-colour fluorescence in situ hybridization (FISH) was performed to study the chromosomal distribution of 18S and 5S rDNAs, (GATA)(n) and 5S rDNA, and U2 snRNA and 18S rDNA in four species of Batrachoididae family: Amphichthys cryptocentrus, Batrachoides manglae, Porichthys plectrodon and Thalassophryne maculosa. The 18S rDNA signals were present in only one pair of chromosomes in all the four Batrachoididae species. The 5S rDNA was mapped on one pair of chromosomes, except in B. manglae, which showed a hybridization signal in two pairs. The two ribosomal genes are located on different chromosome pairs, except in A. cryptocentrus, in which they appear co-located. In all the cases, the (GATA)(n) probe produced disperse hybridization signals in all four species. The U2 snRNA signals appear very widely scattered in A. cryptocentrus, P. plectrodon, but show a degree of clustering in a specific chromosome pair in B. manglae. In T. maculosa, they are thinly dispersed and strong hybridization signals are observed co-located to the 18S rDNA-bearing chromosomes. Finally, a double-colour FISH with U2 snRNA and 5S rDNA probes was performed in B. manglae, and this showed that these genes were not co-located. These results have been compared with those from another Batrachoididae species, and evolutive processes of these species are discussed.

Comparative Chromosome Mapping of U2 snRNA and 5S rRNA Genes in <b><i>Gymnotus</i></b> Species (Gymnotiformes, Gymnotidae): Evolutionary Dynamics and Sex Chromosome Linkage in <b><i>G</i></b>. <b><i>pantanal</i></b>

“…For example, from the 5 existing subtypes of U snRNA genes, U1 snDNA was mapped only in cichlid species, and its position was highly conserved, with a single pair of U1 snDNA-bearing chromosomes for all analyzed species [Cabral-de-Mello et al, 2012]. Conversely, U2 snDNA cluster location was reported in 5 Batrachoididae, 2 Moronidae, 1 Bagridae, and 1 Haemulidae species [Merlo et al, , 2012aÚbeda-Manzanaro et al, 2010;Supiwong et al, 2013] and evidenced a more diversified scenario, particularly in the Batrachoididae family with species presenting (i) compartmentalization of this sequence in a single pair, (ii) a very widely scattered distribution throughout all chromosomes, or (iii) simultaneous scattered and compartmentalized organization [Úbeda-Manzanaro et al, 2010]. Here, we show that the U2 snDNA is compartmentalized and the number of U2 snDNAbearing chromosomes is conserved in Gymnotus .…”

“…cluding transposable elements, histone genes, microsatellite repeats and/or U1/U2 small nuclear RNA (snRNA) genes [Cioffi et al, 2010;Úbeda-Manzanaro et al, 2010;Ferreira et al, 2011;Hashimoto et al, 2011;Cabral-deMello et al, 2012]. The U snDNA is a multigene family of non-coding RNAs that compounds the spliceosome machinery and may be subdivided into 5 types, including U1, U2, U4, U5, and U6 [Valadkhan, 2005].…”

“…The U snDNA is a multigene family of non-coding RNAs that compounds the spliceosome machinery and may be subdivided into 5 types, including U1, U2, U4, U5, and U6 [Valadkhan, 2005]. Although highly suitable for use as FISH probes, these sequences have been mapped in only few fish until now, U1 in 19 cichlid species [Cabral-de-Mello et al, 2012] and U2 in 8 species [Merlo et al, , 2012aÚbeda-Manzanaro et al, 2010;Supiwong et al, 2013]. Although scarce, data on physical mapping of U snRNA genes in different organisms evidence that these sequences may be linked with other multigene families [Pelliccia et al, 2001;Manchado et al, 2006], may present distinct patterns of chromosomal organization [Úbedo-Manzanaro et al, 2010] and may be allocated in sex or supernumerary chromosomes [Bueno et al, 2013;Palacios-Gimenez et al, 2013].…”

Analysis of three multigene families as useful tools in species characterization of two closely-related species, Dicentrarchus labrax, Dicentrarchus punctatus and their hybrids

“…However, cases have been reported in which the two ribosomal genes are in the same locus (Cross et al, 2006;Fujiwara et al, 2007;Diniz et al, 2008). The U2 snRNA gene has been applied Within the fish group, only one work has reported the location of this probe, in four Batrachoididae species, and in that case the authors found three hybridization patterns: concentrated in one chromosome pair; dispersed through the genome; or both concentrated and dispersed (Úbeda-Manzanaro et al, 2010a). Recently, double-FISH studies with the same probes have been carried out in three species of Sparidae family (Merlo et al, in revision).…”

In situ Localization of (GATA)n and (TTAGGG)n Repeated DNAs and W Sex Chromosome Differentiation in Parodontidae (Actinopterygii: Characiformes)

“…In some fish species, studies with (GATA)n repeats showed a dispersed localization throughout the chromosomes without any kind of preferential accumulation [Cross et al, 2006;Úbeda-Manzanaro et al, 2010;Traldi et al, 2013]. Although some (GATA)n clusters were detected in chromosomes of Parodontidae, especially in the sex chromosomes, an extensive number of dispersed copies in the karyotype is evident.…”