Transient Darwinian selection in Salmonella enterica serovar Paratyphi A during 450 years of global spread of enteric fever

Zhou, Zhemin, McCann, Angela, Weill, François-Xavier, Blin, Camille, Nair, Satheesh, Wain, John, Dougan, Gordon and Achtman, Mark (2014) Transient Darwinian selection in Salmonella enterica serovar Paratyphi A during 450 years of global spread of enteric fever. Proceedings of the National Academy of Sciences of the United States of America (PNAS), 111 (33). pp. 12199-204. ISSN 1091-6490

Full text not available from this repository. (Request a copy)

Abstract

Multiple epidemic diseases have been designated as emerging or reemerging because the numbers of clinical cases have increased. Emerging diseases are often suspected to be driven by increased virulence or fitness, possibly associated with the gain of novel genes or mutations. However, the time period over which humans have been afflicted by such diseases is only known for very few bacterial pathogens, and the evidence for recently increased virulence or fitness is scanty. Has Darwinian (diversifying) selection at the genomic level recently driven microevolution within bacterial pathogens of humans? Salmonella enterica serovar Paratyphi A is a major cause of enteric fever, with a microbiological history dating to 1898. We identified seven modern lineages among 149 genomes on the basis of 4,584 SNPs in the core genome and estimated that Paratyphi A originated 450 y ago. During that time period, the effective population size has undergone expansion, reduction, and recent expansion. Mutations, some of which inactivate genes, have occurred continuously over the history of Paratyphi A, as has the gain or loss of accessory genes. We also identified 273 mutations that were under Darwinian selection. However, most genetic changes are transient, continuously being removed by purifying selection, and the genome of Paratyphi A has not changed dramatically over centuries. We conclude that Darwinian selection is not responsible for increased frequency of enteric fever and suggest that environmental changes may be more important for the frequency of disease.

Item Type: Article
Uncontrolled Keywords: genes, bacterial,humans,polymorphism, single nucleotide,salmonella enterica,selection, genetic,typhoid fever,world health
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Pure Connector
Date Deposited: 12 Nov 2014 16:48
Last Modified: 21 Apr 2020 23:33
URI: https://ueaeprints.uea.ac.uk/id/eprint/50744
DOI: 10.1073/pnas.1411012111

Actions (login required)

View Item View Item