A satellite DNA of the Sparidae family (Pisces, Perciformes) associated with telomeric sequences

Abstract

This paper reports on the isolation and localization of the subtelomeric DraI satellite DNA in the Sparidae family. Gene cloning determined that the DraI satellite DNA is present in only 3 species (Pagrus pagrus, P. auriga, and Pagellus erythrinus) of the 10 Sparidae species analyzed. The results were confirmed by PCR amplification. This satellite DNA is located in a subtelomeric position in all 48 acrocentric chromosomes of these species. However, interstitial loci are also observed. Sequence analysis of monomers of this repetitive family indicates that the satellite DNA is associated with telomeric sequences, (TTAGGG)_n, in at least one species, P. erythrinus. This is the first direct demonstration of the existence of the consensus telomere sequences of vertebrates in fish. Likewise, this report also demonstrates that the ends of fish chromosomes have a structure similar to those of most eukaryote chromosomes, viz., telomere sequences and subtelomeric sequences associated by a boundary in which both types of sequences are interspersed. The recent origin of the DraI satellite DNA and its use as a phylogenetic marker is discussed.

Autosomal localization of interstitial telomeric sites (ITS) in brook trout, <i>Salvelinus fontinalis</i> (Pisces, Salmonidae)

“…The reduction of the chromosome number from 2n = 48, which is supposed to be ancestral for teleost fish (Brum and Galetti, 1997), to 2n = 44 in Nile tilapia (Oreochromis niloticus) by fusion of three chromosomes, left two interstitial telomeric sites on the two largest chromosomes in its karyotype (Chew et al, 2002). On the other hand, in some vertebrate species, the (TTAGGG) n sequence has been reported as a component of the satellite DNA (Adegoke et al, 1993) which can be located in subtelomeric as well as interstitial positions in chromosomes (Garrido-Ramos et al, 1998). Finally, it is important to note that guanine-rich elements such as variable number of tandem repeats (VNTR) or NOR-regions (Ashley and Ward, 1993) are listed besides telomeres and centromeres as elements involved in jumping translocation processes followed by ITS formation.…”

Evolution of Centromeric Satellite DNA and Its Use in Phylogenetic Studies of the Sparidae Family (Pisces, Perciformes)

“…This phylogeny of the Sparidae family is also supported by previous data obtained from the analysis of another satellite DNA, the DraI family, found within the genome of some sparids. While EcoRI is a satellite DNA family conserved in every sparid species, the DraI satellite DNA is restricted to the genome of the species of Pagrus and Pagellus, and it is absent from the genome of the rest of species belonging to a different clade (Garrido-Ramos et al, 1995a, 1998. It is also noteworthy that the species belonging to one of the lineages (Pagrus and Pagellus) are the last species maintaining the ancestral karyotype of fish composed of 48 acrocentric chromosomes (Ohno, 1974), while the species of the other lineage have derived karyotypes (Garrido-Ramos, 1994).…”

Genomic Distribution of Telomeric DNA Sequences – What Do We Learn from Fish About Telomere Evolution?

“…Although it is still unknown how the telomeric DNA sequences were inserted into the interstitial positions and amplified, the repair of the DNA Double Strand Breaks with the telomerase should be taken into consideration (Nergadze et al, 2004(Nergadze et al, , 2007. Previously, several authors suggested that telomeric or telomeric like DNA sequences were components of the satellite DNA in some vertebrates (Garrido-Ramos et al, 1998). In other species, telomeric DNA sequences are scattered along the NORs (Nucleolus Organizer Region) DNA sequences (see chapter 4.4).…”

“…It is possible that telomeric DNA sequences were not the only component of the ITS region. Internally inserted short telomeric repeats are frequently flanked by the repetitive or transposable elements and undergo amplification process leading to elongation/expansion of the chromatic region built with different DNA sequences including telomeric repeats (Garrido-Ramos et al, 1998).…”