The DNA sequence of a 612-nucleotide fragment of the mitochondrial cytochrome oxidase subunit III gene (CO III) from three Mediterranean octopodid species namely: Octopus vulgaris, O. macropus and Eledonmoschata, has been determined. The perecentage of nucleotide composition of A/T,C/G was investigated. The CO III gene in these species revealed higher values of A+T against moderately low G+C content. COMPARE computer software program was applied for determining the percentage of pairwise sequence differences (P) between different species.
The results of the present work are discussed with those previously obtained for O. bimaculoides, O. bimaculatus, O. dofleini, O. rubescens, O. cyanea and O. californicus. They indicated that O.vulgaris and O. macropus belong to the DNA distance-based tree of O. bimaculatu