Comparative evolutionary genomics of Corynebacterium with special reference to codon and amino acid usage diversities

Abstract

The present study has been aimed to the com- parative analysis of high GC composition containing

Corynebacterium genomes and their evolutionary study by

exploring codon and amino acid usage patterns. Phyloge- netic study by MLSA approach, indel analysis and BLAST

matrix differentiated Corynebacterium species in pathogenic and non-pathogenic clusters. Correspondence analysis on synonymous codon usage reveals that, gene length, optimal codon frequencies and tRNA abundance affect the gene expression of Corynebacterium. Most of the optimal codons as well as translationally optimal codons are C ending i.e. RNY (R-purine, N-any nucleotide base, and Y-pyrimidine) and reveal translational selection pressure on codon bias of

Corynebacterium. Amino acid usage is affected by hydro- phobicity, aromaticity, protein energy cost, etc. Highly

expressed genes followed the cost minimization hypoth- esis and are less diverged at their synonymous positions of

codons. Functional analysis of core genes shows significant

difference in pathogenic and non-pathogenic Corynebac- terium. The study reveals close relationship between non- pathogenic and opportunistic pathogenic Corynebaterium

as well as between molecular evolution and survival niches of the organism.