1. Institut für Molekulare Evolution, Heinrich Heine Universität, 40225 Düsseldorf, Germany
2. Konrad Lorenz Institute for Evolution and Cognition Research, 3400 Klosterneuburg, Austria
3. Institute for Systems Biology, Seattle, WA 98109-5263, USA
4. Biomathematics Research Centre, University of Canterbury, Christchurch 8041, New Zealand
5. Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal