Unit of Genetics of Bacterial Genomes, Institut Pasteur, URA CNRS 2171, Cedex 15, Paris, France. makita@hgc.jp <makita@hgc.jp>|Unit of Genetics of Bacterial Genomes, Institut Pasteur, URA CNRS 2171, Cedex 15, Paris, France. makita@hgc.jp <makita@hgc.jp>|Unit of Genetics of Bacterial Genomes, Institut Pasteur, URA CNRS 2171, Cedex 15, Paris, France. makita@hgc.jp <makita@hgc.jp>