Gene inversion potentiates bacterial evolvability and virulence

• Published in: Nature communications Vol. 9; no. 1; pp. 4662 - 10
• Main Authors: Merrikh, Christopher N, Merrikh, Houra
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 07.11.2018; Nature Publishing Group UK; Nature Portfolio
• Subjects: Alleles; Antibiotic resistance; Antibiotics; Bacteria; Bacteria - genetics; Bacteria - pathogenicity; Base Composition - genetics; Base Sequence; Biological Evolution; Collisions; Deoxyribonucleic acid; Divergence; DNA; DNA, Bacterial - genetics; Drug Resistance, Microbial - genetics; Genes; Genes, Bacterial; Genomes; Inversion; Inversions; Mutation; Mutation Rate; Mutation rates; Orientation; Pathogens; Phylogeny; Positive selection; Replication; Ribonucleic acid; RNA; Selection, Genetic; Species Specificity; Time Factors; Transcription; Virulence; Virulence - genetics
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-07110-3

Most bacterial genes are encoded on the leading strand, co-orienting the movement of the replication machinery with RNA polymerases. This bias reduces the frequency of detrimental head-on collisions between the two machineries. The negative outcomes of these collisions should lead to selection against head-on alleles, maximizing genome co-orientation. Our findings challenge this model. Using the GC skew calculation, we reveal the evolutionary inversion record of all chromosomally encoded genes in multiple divergent bacterial pathogens. Against expectations, we find that a large number of co-oriented genes have inverted to the head-on orientation, presumably increasing the frequency of head-on replication-transcription conflicts. Furthermore, we find that head-on genes, (including key antibiotic resistance and virulence genes) have higher rates of non-synonymous mutations and are more frequently under positive selection (dN/dS > 1). Based on these results, we propose that spontaneous gene inversions can increase the evolvability and pathogenic capacity of bacteria through head-on replication-transcription collisions.