RNAbinding peptides as molecular fossils

Abstract

Comparisons of complete cellular genomes indicate that a set of genes whose products sqnthesize, degrade, or interact with RNA molecules are among the most highly conserved sequences common to all living beings, and therefore may have been present in their last common ancestor, i.e., the cenancestor. In order to obtain insights on the evolution of sequences which may date freom an early evolutionary period during which RNA played a genetic role prior to the emergence of DNA genomes, we have analyzed the conserved RNAbinding sites of these highly conserved molecules, since these may be some of the recognizable peptides in our dataset. The characteristics of some of these highly conserved amino acid stretches which are essential in RNA metabolism are discussed.