The sequence arrangement of an eukaryotic organelle DNA (ct DNA of Euglena gracilis) will be determined by mapping with restriction endonuclease. Fragments produced by maximum cleavage with EcoR1 restriction endonuclease will be identified. The proper sequence of the fragments in the circular DNA molecule will be determined. Location of genes on the restriction map will be initiated by identifying fragments which code for rRNA and locating the site for initiating DNA synthesis.