Gene inversion increases evolvability in bacteria

In bacteria, most genes are encoded on the leading strand, co-orienting the movement of the replication machinery with RNA polymerases. This co-orientation bias reduces the frequency of highly detrimental head-on collisions between the two machineries. This and other work set up the expectation that...

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Bibliographic Details
Published inbioRxiv
Main Authors Merrikh, Christopher N, Merrikh, Houra
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 03.04.2018
Subjects
Antibiotic resistance
Bacteria
Genes
Genomes
Head
Inversion
Positive selection
Replication
Ribonucleic acid
RNA
Transcription
Virulence
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Summary:In bacteria, most genes are encoded on the leading strand, co-orienting the movement of the replication machinery with RNA polymerases. This co-orientation bias reduces the frequency of highly detrimental head-on collisions between the two machineries. This and other work set up the expectation that over evolutionary time, head-on alleles are selected against, maximizing genome co-orientation. Our findings challenge this model. Using the well-established GC skew method, we reveal the evolutionary inversion record of all chromosomally encoded genes in multiple divergent bacterial pathogens. We find that a surprisingly large number of co-oriented genes have inverted to, and are retained in the head-on orientation. Furthermore, we find that these head-on genes, (including key antibiotic resistance and virulence genes) have higher rates of nonsynonymous mutations and are more frequently under positive selection (dN/dS>1). Based on these results, we propose that bacteria increase their evolvability through gene inversion and promotion of head-on replication-transcription collisions.
DOI:10.1101/293571