1 Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, Brno, Czech Republic. Electronic address: reichard@ivb.cz.
2 Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, Italy; Fritz Lipmann Institute for Age Research, Leibniz Institute, Beutenbergstr. 11, Jena, Germany.
3 Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, Cologne, Germany.