1. Institute of Microbiology and Genetics, Vienna Biocenter, University of Vienna; Dr Bohrgasse 9, 1030 Vienna Austria
2. Laboratory of Genetics, Department of Biology, University of Camerino; 62032 Camerino Italy
3. Department of Medical Biochemistry and Medical Biology, University of Bari; 70124 Bari Italy
4. Department of Cellular Biotechnologies and Hematology, University of Rome; 00161 Rome Italy