ABSTRACT
The use of mitochondrial DNA as a phylogentic marker provides a new source of information to solve molecular evolution problems. Although the gene content and mode of organization of animal mt genomes is universally conserved across animal kingdom, organisms belonging to different taxa show profound differences in the gene order. The analysis of mt gene organization in the echinoids show that echinoids and asteroids have a different gene order. The extension of this study to the five echinoderm classes, will allow to establish their precise phylogenetic relationships. At phyla level the com parison of gene orders will be used to gain knowledge abouth the relationships among the primary branches in metazoan.
