Global Topology of Codon Usage Equality Networks of Escherichia Coli Essential Genes

Relation between codon usage and other biological phenomena in living organisms, has been proved in previous researches. In advance, recently, it is shown that the codon usage of co-expressed and co-function genes are similar. In this paper, we introduced a set of networks called codon usage equality networks, each network for an amino acid. These networks represent codon usage similarities between genes. We showed that, at least some of these networks have scale-free and small world properties. Also we showed that betweenness centrality and degree of network nodes are related proportionally. We also compared the networks for different amino acids. We showed that among all codon usage equality networks of different amino acids, networks corresponding to amino acids “Proline”, “Valine”, and “Arginine” are more similar to each other.