Origin Of Life: Issues

The Genetic and Metabolic Views of the Origin of Life

In all contemporary organisms, a distinction can be made between genotype and phenotype. The degree to which early organisms had 'genotypes' and 'phenotypes' is an important issue facing those wishing to understand the nature of the first organisms. Opinion on this matter has tended to be divided between those emphasising the rôle of the genotype and those emphasising the rôle of the phenotype. These views can be characterised as follows:-

Most proponents of the Genetic View have envisaged the first replicators as RNA-like molecules. As indicated in the section on transfer of hereditary information, the Error Threshold represents a difficulty for this view, since in order to enable hereditary information to be transferred adequately, it places a very low limit on the size of RNA-like replicators. Eigen's Hypercycle theory is an attempt to overcome this difficulty.

The Metabolic View has been criticised on the basis that it is difficult to see how hereditary information can be transferred from 'parent' to 'child'. Theories of Autocatalytic Sets and Compositional Inheritance attempt to overcome this difficulty.