1. Department of Medical Biology, Faculty of Medicine, University of Szeged, Somogyi B. u. 4., Szeged H-6720, Hungary
2. Department of Genetics, School of Medicine, Stanford University, 300 Pasteur Dr., Stanford, CA 94305-5120, USA
3. Department of Biotechnology, Faculty of Science and Informatics, University of Szeged, Középfasor 52., Szeged H-6726, Hungary