ON THE APPEARANCE OF FUNCTION AND ORGANIZATION IN THE ORIGIN OF LIFE

Models for the steps of organisation in the origin of life are discuss ed with an emphasis on stability, and the possibilities of acquiring a diversity of functions. In particular, two basic models are described : that of simple self-replicating molecules, and that of autocatalytic self-reproduction, which is accomplished by a hypercyclic organisatio n. The latter may be exemplified by the RNA world. The view of a step- wise development with new functions successively incorporated and a hi gh accuracy of the reproduction from the onset is criticised. Instead, we suggest that no clear systematic information is continued to the f irst cell before the start of protein synthesis. A non-selective manif old of self-replicating molecules and unsystematic protein production from the beginning could have caused a very large diversity from which functions that could stabilise the system by feedback loops could be selected. The only way to stabilise the protein synthesis and the gene tic code would be to have feedback mechanisms so that the code actuall y produced the proteins that supported that very code. The code would then become frozen. As DNA would require control functions, it would n ot be used as a single information-carrier until protein synthesis had been established and the functions were available. (C) 1997 Academic Press Limited.