Fluorescence in situ hybridization of rDNA, telomeric (TTAGGG)n and (GATA)n repeats in the red abalone Haliotis rufescens (Archaeogastropoda: Haliotidae)

Abstract

The physical location of 18S-5.8S-28S rDNA, telomeric sequences with (TTAGGG)n DNA probe and (GATA)n microsatellites were performed by fluorescence in situ hybridization in chromosomes of red abalone Haliotis rufescens. The karyotype of red abalone showed a diploid number of 36 (8M+9SM+1ST). FISH performed with rDNA probe, showed the location of major ribosomal clusters in the terminal region of the large arms of two submetacentric pairs (chromosome 4 and 5). Localization of heteromorphisms of FISH-rDNA was found between chromosome homologues and sister chromatids in all metaphases analyzed. This indicates that rDNA clusters are variable within the red abalone genome. The variability in the NOR-bearing reported using silver staining in other gastropods and our result are discussed. In addition, the presence of microsatellite (TTAGGG)n and (GATA)n was demonstrated after FISH treatment by DNA probes. The telomeric sequence occurred at the ends of all mitotic chromosomes, while the (GATA)n repetitive was found on chromosomal interstitial zones as well as at the telomeres in abalone chromosomes.

Two different and functional nuclear rDNA genes in the abalone Haliotis tuberculata: tissue differential expression

“…Within the Haliotis rufescens species, characterized by 18 pairs of chromosomes, heteromorphism is important and two ribosomal clusters were located by means of in situ hybridization on two different pairs of chromosomes (Gallardo-Escararte et al 2005). This result confirmed (Okumora et al 1999), both thereby providing preliminary evidence for functional duplication.…”

“…This discrepancy was not explained. Coupled with the fact that, in Haliotis rufescens, at least two rDNA clusters were shown to exist on the terminal ends of the large arms of the two submetacentric chromosomes 4 and 5 by means of in situ hybridization, (Gallardo-Escararte et al 2005), the question of duplications of the 18S rDNA and their role in abalone, remains outstanding.…”

Cytogenetic characterization of the sole Solea senegalensis (Teleostei: Pleuronectiformes: Soleidae): Ag-NOR, (GATA) n , (TTAGGG) n and ribosomal genes by one-color and two-color FISH

“…The (GATA) n has been associated with the sex in some species (Demas & Wachtel, 1991;Subramanian, Mishra & Singh, 2003). In spite of being a potential marker associated with the sex and evolution, the localization of the (GATA) n by means of FISH has been used rarely Gallardo-Esca´rate et al, 2005). However, the recent finding that GATA repeats have been gradually accumulated in highly evolved organisms (Subramanian, Mishra & Singh, 2003), has converted this sequence into a valuable tool to be used in studies of cytogenetic characterization.This paper contains a first approach to the molecular characterization of the Sole (Solea senegalensis) and it provides some valuable cytogenetic markers in the study of phylogenetic relationships in Pleuronectiformes.…”

Karyotypic characterization and genomic organization of the 5S rDNA in Polypterus senegalus (Osteichthyes, Polypteridae)

“…The localization of these sequences by means of FISH has been used rarely in lower groups Gallardo Escàrate et al 2005), also if recent findings that GATA have been accumulated gradually in highly evolved organisms have reconverted them into an interesting molecular marker for cytogenetic characterization. In fish species GATA repeats are not associated with a particular sex and FISH signals are dispersed along the whole chromosomal structure (Wachtel et al 1991;Tiersh et al 1992;Cross et al 2006).…”