GENETIC REDUNDANCY AND THE ORIGIN OF CHROMOSOMES

摘要

The co-existence of distinct selfish genes or templates seems to be a prerequisite for the evolution of complex cellular life. In fact, this co-existence has been advanced as a solution to the information crisis of prebiotic evolution and has served as motivation for the proposal of two competing information integration models - the hypercycle and the gene-package models. However, recent studies have shown that both models suffer from the same deficiency, namely, in presence of mutants the total amount of information is constant, regardless of the number of co-existing templates. The two main hindrances to achieving coexistence in the package model framework are the competition between template types within the packages (i.e., primitive cells) and the loss of template types during the binary fission of the cells. Apparently, these problems can be solved by a single artifact - the template linkage in chromosomes. Here we investigate the viability of this solution by studying the fate of a primordial chromosome in a population of free genes. Analysis of the probability of fixation of the chromosome in the population indicates that the chromosome lineage prospers only for unrealistically small cells, which would be doomed due to the lack of genetic redundancy well before the emergence of the ancestral chromosome.