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Mutation rate dynamics reflect ecological change in an emerging zoonotic pathogen.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Murray, Gemma GR 
Balmer, Andrew J 
Herbert, Josephine 
Hadijirin, Nazreen F 
Kemp, Caroline L 

Abstract

Mutation rates vary both within and between bacterial species, and understanding what drives this variation is essential for understanding the evolutionary dynamics of bacterial populations. In this study, we investigate two factors that are predicted to influence the mutation rate: ecology and genome size. We conducted mutation accumulation experiments on eight strains of the emerging zoonotic pathogen Streptococcus suis. Natural variation within this species allows us to compare tonsil carriage and invasive disease isolates, from both more and less pathogenic populations, with a wide range of genome sizes. We find that invasive disease isolates have repeatedly evolved mutation rates that are higher than those of closely related carriage isolates, regardless of variation in genome size. Independent of this variation in overall rate, we also observe a stronger bias towards G/C to A/T mutations in isolates from more pathogenic populations, whose genomes tend to be smaller and more AT-rich. Our results suggest that ecology is a stronger correlate of mutation rate than genome size over these timescales, and that transitions to invasive disease are consistently accompanied by rapid increases in mutation rate. These results shed light on the impact that ecology can have on the adaptive potential of bacterial pathogens.

Description

Funder: Raymond and Beverly Sackler Foundation


Funder: Isaac Newton Trust


Funder: Newnham College, University of Cambridge


Funder: Medical Research Council

Keywords

Adaptation, Biological, Animals, Communicable Diseases, Emerging, Ecology, Mutation Rate, Streptococcal Infections, Streptococcus suis, Virulence, Zoonoses

Journal Title

PLoS Genetics

Conference Name

Journal ISSN

1553-7390
1553-7404

Volume Title

17

Publisher

Public Library of Science (PLoS)
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/L018934/1)
Wellcome Trust (109385/Z/15/Z)
European Commission Horizon 2020 (H2020) Societal Challenges (727966)
BBSRC (2113638)
Medical Research Council (1933099)
MRC (MR/V032836/1)
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