on. Biophys Clem 26: 123-147. 21. Fontana W. Schuster P (1998; Continuity in evolution: On the nature of transitions. Science 280: 1451 1455. 22. Eigeii M. Mccaskilli. Schuster P (19118) Molecular quasi.species..) Phys Clem 92: 6881 6891. 23. Eigen NI. Schumer P (1978) The hypercycle. Natuncissenschalien 65: 7 41