Comparative chromosomal mapping in Triportheus fish species. Analysis of synteny between ribosomal genes

► We investigated the distribution of the 5S and 18S rDNA sites on Triportheus fish species by means of the double-FISH technique. ► We were able to determine that these gene sites are syntenical in some of the Triportheus species. ► The syntenical location of the ribosomal genes might be an ancestral trait in Triportheus which was changed in some species during evolution.