ABSTRACT
This chapter is based on the premise that natural selection acted to minimise the deleterious effects of (expressed) genetic errors during the early phases of evolution, when many familiar features of the genetic apparatus were ‘fixed’. According to this thesis many key features of the information- transmitting system of cells may be viewed as adaptive responses to the heavy error load placed on early genomes by their inability to correct errors made during copying or introduced from the environment. These features include;
diploidy and reciprocal recombination in eukaryotes;
genome segmentation among RNA viruses and;
the processing system which excises introns from RNA precursors.
