MOLECULAR PHYLOGENY OF THREE OCTOPODID SPECIES FROM THE MEDITERRANEAN WATER, EGYPT

ABSTRACT he 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 Etedonmoschata, 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, dofleinU 0. O. rubescens, O. cyanea and O. californicus. They indicated that 0{vulgaris and 0. macropus belong to the DNA distance-based tree of O, bimaculatus, while E. moschata is an outgroup in relation to the other species. INTRODUCTION Most of the previous attempts to identify and classify cephalopods had been based on external morphology, internal structure, behaviour and skin patterning (Robson, 1925,1929 & 1932; Packard & Hochberg ,1977; Voss & Voss ,1983 ; Hanlon,1988). The phylogenetic relationship between