Comparative analysis of a mitochondrial DNA control region fragment amplified from three Adriatic flatfish species and molecular phylogenesis of Pleuronectiformes

The 5'-end of the mitochondrial control region of three Pleuronectiformes f rom the Adriatic Sea, Platichthys flesus italicus (Adriatic flounder), Sole a vulgaris (common sole), and Solea kleini (Klein's sole), was sequenced an d compared with that of six other flatfish species from the families Pleuro nectidae and Bothidae. The sequence structures of all flatfishes appear ver y similar and consist of:alternate short segments with low, medium, and hig h rates of nucleotide substitution. Four conserved 19-bp repeats occur at t he beginning of the European and Adriatic flounder sequences. The common oc currence of tandem arrays in fish control regions could be related to a sta ble secondary structure. Molecular phylogenetic relationships among Pleuron ectiformes agree well with previous morphologic data at all taxonomic level s. Molecular analyses: could therefore contribute to resolving phylogenetic and taxonomic debates within the Pleuronectiformes.