1
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Mei Z, Wang F, Bhosle A, Dong D, Mehta R, Ghazi A, Zhang Y, Liu Y, Rinott E, Ma S, Rimm EB, Daviglus M, Willett WC, Knight R, Hu FB, Qi Q, Chan AT, Burk RD, Stampfer MJ, Shai I, Kaplan RC, Huttenhower C, Wang DD. Strain-specific gut microbial signatures in type 2 diabetes identified in a cross-cohort analysis of 8,117 metagenomes. Nat Med 2024; 30:2265-2276. [PMID: 38918632 DOI: 10.1038/s41591-024-03067-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/14/2024] [Indexed: 06/27/2024]
Abstract
The association of gut microbial features with type 2 diabetes (T2D) has been inconsistent due in part to the complexity of this disease and variation in study design. Even in cases in which individual microbial species have been associated with T2D, mechanisms have been unable to be attributed to these associations based on specific microbial strains. We conducted a comprehensive study of the T2D microbiome, analyzing 8,117 shotgun metagenomes from 10 cohorts of individuals with T2D, prediabetes, and normoglycemic status in the United States, Europe, Israel and China. Dysbiosis in 19 phylogenetically diverse species was associated with T2D (false discovery rate < 0.10), for example, enriched Clostridium bolteae and depleted Butyrivibrio crossotus. These microorganisms also contributed to community-level functional changes potentially underlying T2D pathogenesis, for example, perturbations in glucose metabolism. Our study identifies within-species phylogenetic diversity for strains of 27 species that explain inter-individual differences in T2D risk, such as Eubacterium rectale. In some cases, these were explained by strain-specific gene carriage, including loci involved in various mechanisms of horizontal gene transfer and novel biological processes underlying metabolic risk, for example, quorum sensing. In summary, our study provides robust cross-cohort microbial signatures in a strain-resolved manner and offers new mechanistic insights into T2D.
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Affiliation(s)
- Zhendong Mei
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Fenglei Wang
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Amrisha Bhosle
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Danyue Dong
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Raaj Mehta
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Andrew Ghazi
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Yancong Zhang
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Yuxi Liu
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Ehud Rinott
- Department of Medicine, Hebrew University and Hadassah Medical Center, Jerusalem, Israel
| | - Siyuan Ma
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric B Rimm
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Martha Daviglus
- Institute for Minority Health Research, University of Illinois Chicago, Chicago, IL, USA
| | - Walter C Willett
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Rob Knight
- Center for Microbiome Innovation, Jacobs School of Engineering, University of California San Diego, La Jolla, CA, USA
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA
| | - Frank B Hu
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Qibin Qi
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Andrew T Chan
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Robert D Burk
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Obstetrics, Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Meir J Stampfer
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Iris Shai
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Faculty of Health Sciences, The Health and Nutrition Innovative International Research Center, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Robert C Kaplan
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Curtis Huttenhower
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Harvard Chan Microbiome in Public Health Center, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
| | - Dong D Wang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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2
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Atkins H, Sabharwal B, Boger L, Stegman N, Kula A, Wolfe AJ, Banerjee S, Putonti C. Evidence of Lactobacillus strains shared between the female urinary and vaginal microbiota. Microb Genom 2024; 10:001267. [PMID: 38949867 PMCID: PMC11316553 DOI: 10.1099/mgen.0.001267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 06/14/2024] [Indexed: 07/02/2024] Open
Abstract
Lactobacillus species are common inhabitants of the 'healthy' female urinary and vaginal communities, often associated with a lack of symptoms in both anatomical sites. Given identification by prior studies of similar bacterial species in both communities, it has been hypothesized that the two microbiotas are in fact connected. Here, we carried out whole-genome sequencing of 49 Lactobacillus strains, including 16 paired urogenital samples from the same participant. These strains represent five different Lactobacillus species: L. crispatus, L. gasseri, L. iners, L. jensenii, and L. paragasseri. Average nucleotide identity (ANI), alignment, single-nucleotide polymorphism (SNP), and CRISPR comparisons between strains from the same participant were performed. We conducted simulations of genome assemblies and ANI comparisons and present a statistical method to distinguish between unrelated, related, and identical strains. We found that 50 % of the paired samples have identical strains, evidence that the urinary and vaginal communities are connected. Additionally, we found evidence of strains sharing a common ancestor. These results establish that microbial sharing between the urinary tract and vagina is not limited to uropathogens. Knowledge that these two anatomical sites can share lactobacilli in females can inform future clinical approaches.
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Affiliation(s)
- Haley Atkins
- Bioinformatics Program, Loyola University Chicago, Chicago, IL, USA
| | - Baani Sabharwal
- Department of Molecular Environmental Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Leah Boger
- Data Science Program, Loyola University Chicago, Chicago, IL, USA
| | - Natalie Stegman
- Bioinformatics Program, Loyola University Chicago, Chicago, IL, USA
| | - Alexander Kula
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
| | - Alan J. Wolfe
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
| | - Swarnali Banerjee
- Data Science Program, Loyola University Chicago, Chicago, IL, USA
- Department of Mathematics and Statistics, Loyola University Chicago, Chicago, IL, USA
| | - Catherine Putonti
- Bioinformatics Program, Loyola University Chicago, Chicago, IL, USA
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
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3
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Torrance EL, Burton C, Diop A, Bobay LM. Evolution of homologous recombination rates across bacteria. Proc Natl Acad Sci U S A 2024; 121:e2316302121. [PMID: 38657048 PMCID: PMC11067023 DOI: 10.1073/pnas.2316302121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/08/2024] [Indexed: 04/26/2024] Open
Abstract
Bacteria are nonsexual organisms but are capable of exchanging DNA at diverse degrees through homologous recombination. Intriguingly, the rates of recombination vary immensely across lineages where some species have been described as purely clonal and others as "quasi-sexual." However, estimating recombination rates has proven a difficult endeavor and estimates often vary substantially across studies. It is unclear whether these variations reflect natural variations across populations or are due to differences in methodologies. Consequently, the impact of recombination on bacterial evolution has not been extensively evaluated and the evolution of recombination rate-as a trait-remains to be accurately described. Here, we developed an approach based on Approximate Bayesian Computation that integrates multiple signals of recombination to estimate recombination rates. We inferred the rate of recombination of 162 bacterial species and one archaeon and tested the robustness of our approach. Our results confirm that recombination rates vary drastically across bacteria; however, we found that recombination rate-as a trait-is conserved in several lineages but evolves rapidly in others. Although some traits are thought to be associated with recombination rate (e.g., GC-content), we found no clear association between genomic or phenotypic traits and recombination rate. Overall, our results provide an overview of recombination rate, its evolution, and its impact on bacterial evolution.
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Affiliation(s)
- Ellis L Torrance
- Department of Biology, University of North Carolina, Greensboro, NC 27412
| | - Corey Burton
- Department of Biology, University of North Carolina, Greensboro, NC 27412
| | - Awa Diop
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Louis-Marie Bobay
- Department of Biology, University of North Carolina, Greensboro, NC 27412
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
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4
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Carrera Páez LC, Olivier M, Gambino AS, Poklepovich T, Aguilar AP, Quiroga MP, Centrón D. Sporadic clone Escherichia coli ST615 as a vector and reservoir for dissemination of crucial antimicrobial resistance genes. Front Cell Infect Microbiol 2024; 14:1368622. [PMID: 38741889 PMCID: PMC11089171 DOI: 10.3389/fcimb.2024.1368622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/27/2024] [Indexed: 05/16/2024] Open
Abstract
There is scarce information concerning the role of sporadic clones in the dissemination of antimicrobial resistance genes (ARGs) within the nosocomial niche. We confirmed that the clinical Escherichia coli M19736 ST615 strain, one of the first isolates of Latin America that harbors a plasmid with an mcr-1 gene, could receive crucial ARG by transformation and conjugation using as donors critical plasmids that harbor bla CTX-M-15, bla KPC-2, bla NDM-5, bla NDM-1, or aadB genes. Escherichia coli M19736 acquired bla CTX-M-15, bla KPC-2, bla NDM-5, bla NDM-1, and aadB genes, being only blaNDM-1 maintained at 100% on the 10th day of subculture. In addition, when the evolved MDR-E. coli M19736 acquired sequentially bla CTX-M-15 and bla NDM-1 genes, the maintenance pattern of the plasmids changed. In addition, when the evolved XDR-E. coli M19736 acquired in an ulterior step the paadB plasmid, a different pattern of the plasmid's maintenance was found. Interestingly, the evolved E. coli M19736 strains disseminated simultaneously the acquired conjugative plasmids in different combinations though selection was ceftazidime in all cases. Finally, we isolated and characterized the extracellular vesicles (EVs) from the native and evolved XDR-E. coli M19736 strains. Interestingly, EVs from the evolved XDR-E. coli M19736 harbored bla CTX-M-15 though the pDCAG1-CTX-M-15 was previously lost as shown by WGS and experiments, suggesting that EV could be a relevant reservoir of ARG for susceptible bacteria. These results evidenced the genetic plasticity of a sporadic clone of E. coli such as ST615 that could play a relevant transitional link in the clinical dynamics and evolution to multidrug/extensively/pandrug-resistant phenotypes of superbugs within the nosocomial niche by acting simultaneously as a vector and reservoir of multiple ARGs which later could be disseminated.
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Affiliation(s)
- Laura Camila Carrera Páez
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Martin Olivier
- The Research Institute of the McGill University Health Centre, McGill University, Montréal, QC, Canada
| | - Anahí Samanta Gambino
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Tomás Poklepovich
- Plataforma de Genómica y Bioinformática, Instituto Nacional de Enfermedades Infecciosas - La Administración Nacional de Laboratorios e Institutos de Salud (INEI-ANLIS) “Dr. Carlos G. Malbrán”, Buenos Aires, Argentina
| | - Andrea Pamela Aguilar
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - María Paula Quiroga
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Daniela Centrón
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
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5
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Lee IPA, Eldakar OT, Gogarten JP, Andam CP. Recombination as an enforcement mechanism of prosocial behavior in cooperating bacteria. iScience 2023; 26:107344. [PMID: 37554437 PMCID: PMC10405257 DOI: 10.1016/j.isci.2023.107344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/11/2023] [Accepted: 07/06/2023] [Indexed: 08/10/2023] Open
Abstract
Prosocial behavior is ubiquitous in nature despite the relative fitness costs carried by cooperative individuals. However, the stability of cooperation in populations is fragile and often maintained through enforcement. We propose that homologous recombination provides such a mechanism in bacteria. Using an agent-based model of recombination in bacteria playing a public goods game, we demonstrate how changes in recombination rates affect the proportion of cooperating cells. In our model, recombination converts cells to a different strategy, either freeloading (cheaters) or cooperation, based on the strategies of neighboring cells and recombination rate. Increasing the recombination rate expands the parameter space in which cooperators outcompete freeloaders. However, increasing the recombination rate alone is neither sufficient nor necessary. Intermediate benefits of cooperation, lower population viscosity, and greater population size can promote the evolution of cooperation from within populations of cheaters. Our findings demonstrate how recombination influences the persistence of cooperative behavior in bacteria.
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Affiliation(s)
- Isaiah Paolo A. Lee
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
- National Institute of Molecular Biology and Biotechnology, University of the Philippines–Diliman, Quezon City 1101, Philippines
| | - Omar Tonsi Eldakar
- Department of Biological Sciences, Nova Southeastern University, Fort Lauderdale, FL 33328, USA
| | - J. Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Cheryl P. Andam
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
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6
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Lin X, McNichol J, Chu X, Qian Y, Luo H. Cryptic niche differentiation of novel sediment ecotypes of Rugeria pomeroyi correlates with nitrate respiration. Environ Microbiol 2021; 24:390-403. [PMID: 34964547 DOI: 10.1111/1462-2920.15882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/16/2021] [Accepted: 12/18/2021] [Indexed: 10/19/2022]
Abstract
Marine intertidal sediments fluctuate in redox conditions and nutrient availability, and they are also known as an important sink of nitrogen mainly through denitrification, yet how denitrifying bacteria adapt to this dynamic habitat remains largely untapped. Here, we investigated novel intertidal benthic ecotypes of the model pelagic marine bacterium Ruegeria pomeroyi DSS-3 with a population genomic approach. While differing by only 1.3% at the 16S rRNA gene level, members of the intertidal benthic ecotypes are complete denitrifiers whereas the pelagic ecotype representative (DSS-3) is a partial denitrifier lacking a nitrate reductase. The intertidal benthic ecotypes are further differentiated by using non-homologous nitrate reductases and a different set of genes that allow alleviating oxidative stress and acquiring organic substrates. In the presence of nitrate, the two ecotypes showed contrasting growth patterns under initial oxygen concentrations at 1 vol% versus 7 vol% and supplemented with different carbon sources abundant in intertidal sediments. Collectively, this combination of evidence indicates that there are cryptic niches in coastal intertidal sediments that support divergent evolution of denitrifying bacteria. This knowledge will in turn help understand how these benthic environments operate to effectively remove nitrogen.
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Affiliation(s)
- Xingqin Lin
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518000, China
| | - Jesse McNichol
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Xiao Chu
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Yang Qian
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
| | - Haiwei Luo
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518000, China.,Simon F. S. Li Marine Science Laboratory, School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
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7
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Holden N. Genomic data of an environmental Escherichia coli isolate shows high resemblance to E. coli K-12 reference strain MG1655. Data Brief 2021; 39:107586. [PMID: 34849384 PMCID: PMC8609132 DOI: 10.1016/j.dib.2021.107586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/28/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
Escherichia coli species exhibits a high genomic diversification from evolution, mobile genetic elements and recombination. An environmental E. coli isolate, 'JHI_5025' from a crop trial appeared to be clonally related to the historical reference isolate E. coli K-12 strain 'MG1655', warranting further genomic analysis. Their genomes share an average nucleotide identity of 99.74% and whole genome alignment showed little rearrangement of the JHI_5025 sequence compared to the reference. Five genomic islands not in the reference aligned to other sequences in the Enterobacteriaceae. Isolate JHI_5025 contained E. coli K-12 F plasmid sequence and at least one complete prophage sequence. The genome and comparison dataset provides utility of E. coli JHI_5025 as a representative contemporary genetic mimic of a well-known and much used workhorse strain.
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Affiliation(s)
- Nicola Holden
- SRUC, Department of Rural Land Use, Craibstone Estate, Aberdeen AB21 9YA, UK.,Cell and Molecular Sciences, James Hutton Institute, Dundee DD2 5DA, UK
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8
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Pettengill JB, Kase JA, Murray MH. The Population Genetics, Virulence, and Public Health Concerns of Escherichia coli Collected From Rats Within an Urban Environment. Front Microbiol 2021; 12:631761. [PMID: 34777266 PMCID: PMC8585510 DOI: 10.3389/fmicb.2021.631761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
The co-existence of rats and humans in urban environments has long been a cause for concern regarding human health because of the potential for rats to harbor and transmit disease-causing pathogens. Here, we analyze whole-genome sequence (WGS) data from 41 Escherichia coli isolates collected from rat feces from 12 locations within the city of Chicago, IL, United States to determine the potential for rats to serve as a reservoir for pathogenic E. coli and describe its population structure. We identified 25 different serotypes, none of which were isolated from strains containing significant virulence markers indicating the presence of Shiga toxin-producing and other disease-causing E. coli. Nor did the E. coli isolates harbor any particularly rare stress tolerant or antimicrobial resistance genes. We then compared the isolates against a public database of approximately 100,000 E. coli and Shigella isolates of primarily food, food facility, or clinical origin. We found that only one isolate was genetically similar to genome sequences in the database. Phylogenetic analyses showed that isolates cluster by serotype, and there was little geographic structure (e.g., isolation by distance) among isolates. However, a greater signal of isolation by distance was observed when we compared genetic and geographic distances among isolates of the same serotype. This suggests that E. coli serotypes are independent lineages and recombination between serotypes is rare.
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Affiliation(s)
- J B Pettengill
- Division of Biostatistics and Bioinformatics, Office of Analytics and Outreach, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, College Park, MD, United States
| | - J A Kase
- Division of Microbiology, Office of Regulatory Science, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, College Park, MD, United States
| | - M H Murray
- Davee Center for Epidemiology and Endocrinology, Urban Wildlife Institute, Lincoln Park Zoo, Chicago, IL, United States
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9
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Abram K, Udaondo Z, Bleker C, Wanchai V, Wassenaar TM, Robeson MS, Ussery DW. Mash-based analyses of Escherichia coli genomes reveal 14 distinct phylogroups. Commun Biol 2021; 4:117. [PMID: 33500552 PMCID: PMC7838162 DOI: 10.1038/s42003-020-01626-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 12/21/2020] [Indexed: 01/30/2023] Open
Abstract
In this study, more than one hundred thousand Escherichia coli and Shigella genomes were examined and classified. This is, to our knowledge, the largest E. coli genome dataset analyzed to date. A Mash-based analysis of a cleaned set of 10,667 E. coli genomes from GenBank revealed 14 distinct phylogroups. A representative genome or medoid identified for each phylogroup was used as a proxy to classify 95,525 unassembled genomes from the Sequence Read Archive (SRA). We find that most of the sequenced E. coli genomes belong to four phylogroups (A, C, B1 and E2(O157)). Authenticity of the 14 phylogroups is supported by several different lines of evidence: phylogroup-specific core genes, a phylogenetic tree constructed with 2613 single copy core genes, and differences in the rates of gene gain/loss/duplication. The methodology used in this work is able to reproduce known phylogroups, as well as to identify previously uncharacterized phylogroups in E. coli species.
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Affiliation(s)
- Kaleb Abram
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
| | - Zulema Udaondo
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
| | - Carissa Bleker
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, Tennessee, 37996, USA
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Visanu Wanchai
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
| | - Trudy M Wassenaar
- Molecular Microbiology and Genomics Consultants, 55576, Zotzenheim, Germany
| | - Michael S Robeson
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
| | - David W Ussery
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA.
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10
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Sakoparnig T, Field C, van Nimwegen E. Whole genome phylogenies reflect the distributions of recombination rates for many bacterial species. eLife 2021; 10:e65366. [PMID: 33416498 PMCID: PMC7884076 DOI: 10.7554/elife.65366] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/07/2021] [Indexed: 12/26/2022] Open
Abstract
Although recombination is accepted to be common in bacteria, for many species robust phylogenies with well-resolved branches can be reconstructed from whole genome alignments of strains, and these are generally interpreted to reflect clonal relationships. Using new methods based on the statistics of single-nucleotide polymorphism (SNP) splits, we show that this interpretation is incorrect. For many species, each locus has recombined many times along its line of descent, and instead of many loci supporting a common phylogeny, the phylogeny changes many thousands of times along the genome alignment. Analysis of the patterns of allele sharing among strains shows that bacterial populations cannot be approximated as either clonal or freely recombining but are structured such that recombination rates between lineages vary over several orders of magnitude, with a unique pattern of rates for each lineage. Thus, rather than reflecting clonal ancestry, whole genome phylogenies reflect distributions of recombination rates.
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Affiliation(s)
- Thomas Sakoparnig
- Biozentrum, University of Basel, and Swiss Institute of BioinformaticsBaselSwitzerland
| | - Chris Field
- Biozentrum, University of Basel, and Swiss Institute of BioinformaticsBaselSwitzerland
| | - Erik van Nimwegen
- Biozentrum, University of Basel, and Swiss Institute of BioinformaticsBaselSwitzerland
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11
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Bobay LM, O’Donnell AC, Ochman H. Recombination events are concentrated in the spike protein region of Betacoronaviruses. PLoS Genet 2020; 16:e1009272. [PMID: 33332358 PMCID: PMC7775116 DOI: 10.1371/journal.pgen.1009272] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/31/2020] [Accepted: 11/17/2020] [Indexed: 12/24/2022] Open
Abstract
The Betacoronaviruses comprise multiple subgenera whose members have been implicated in human disease. As with SARS, MERS and now SARS-CoV-2, the origin and emergence of new variants are often attributed to events of recombination that alter host tropism or disease severity. In most cases, recombination has been detected by searches for excessively similar genomic regions in divergent strains; however, such analyses are complicated by the high mutation rates of RNA viruses, which can produce sequence similarities in distant strains by convergent mutations. By applying a genome-wide approach that examines the source of individual polymorphisms and that can be tested against null models in which recombination is absent and homoplasies can arise only by convergent mutations, we examine the extent and limits of recombination in Betacoronaviruses. We find that recombination accounts for nearly 40% of the polymorphisms circulating in populations and that gene exchange occurs almost exclusively among strains belonging to the same subgenus. Although experimental studies have shown that recombinational exchanges occur at random along the coronaviral genome, in nature, they are vastly overrepresented in regions controlling viral interaction with host cells.
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Affiliation(s)
- Louis-Marie Bobay
- Department of Biology, University of North Carolina at Greensboro, Greensboro, North Carolina, United States of America
| | - Angela C. O’Donnell
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Howard Ochman
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
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12
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Stott CM, Bobay LM. Impact of homologous recombination on core genome phylogenies. BMC Genomics 2020; 21:829. [PMID: 33238876 PMCID: PMC7691112 DOI: 10.1186/s12864-020-07262-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/19/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Core genome phylogenies are widely used to build the evolutionary history of individual prokaryote species. By using hundreds or thousands of shared genes, these approaches are the gold standard to reconstruct the relationships of large sets of strains. However, there is growing evidence that bacterial strains exchange DNA through homologous recombination at rates that vary widely across prokaryote species, indicating that core genome phylogenies might not be able to reconstruct true phylogenies when recombination rate is high. Few attempts have been made to evaluate the robustness of core genome phylogenies to recombination, but some analyses suggest that reconstructed trees are not always accurate. RESULTS In this study, we tested the robustness of core genome phylogenies to various levels of recombination rates. By analyzing simulated and empirical data, we observed that core genome phylogenies are relatively robust to recombination rates; nevertheless, our results suggest that many reconstructed trees are not completely accurate even when bootstrap supports are high. We found that some core genome phylogenies are highly robust to recombination whereas others are strongly impacted by it, and we identified that the robustness of core genome phylogenies to recombination is highly linked to the levels of selective pressures acting on a species. Stronger selective pressures lead to less accurate tree reconstructions, presumably because selective pressures more strongly bias the routes of DNA transfers, thereby causing phylogenetic artifacts. CONCLUSIONS Overall, these results have important implications for the application of core genome phylogenies in prokaryotes.
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Affiliation(s)
- Caroline M Stott
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, PO Box 26170, Greensboro, NC, 27402, USA
| | - Louis-Marie Bobay
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, PO Box 26170, Greensboro, NC, 27402, USA.
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13
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Van Rossum T, Ferretti P, Maistrenko OM, Bork P. Diversity within species: interpreting strains in microbiomes. Nat Rev Microbiol 2020; 18:491-506. [PMID: 32499497 PMCID: PMC7610499 DOI: 10.1038/s41579-020-0368-1] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2020] [Indexed: 02/06/2023]
Abstract
Studying within-species variation has traditionally been limited to culturable bacterial isolates and low-resolution microbial community fingerprinting. Metagenomic sequencing and technical advances have enabled culture-free, high-resolution strain and subspecies analyses at high throughput and in complex environments. This holds great scientific promise but has also led to an overwhelming number of methods and terms to describe infraspecific variation. This Review aims to clarify these advances by focusing on the diversity within bacterial and archaeal species in the context of microbiomics. We cover foundational microevolutionary concepts relevant to population genetics and summarize how within-species variation can be studied and stratified directly within microbial communities with a focus on metagenomics. Finally, we describe how common applications of within-species variation can be achieved using metagenomic data. We aim to guide the selection of appropriate terms and analytical approaches to facilitate researchers in benefiting from the increasing availability of large, high-resolution microbiome genetic sequencing data.
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Affiliation(s)
- Thea Van Rossum
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Pamela Ferretti
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Oleksandr M Maistrenko
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Peer Bork
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany.
- Max Delbrück Centre for Molecular Medicine, Berlin, Germany.
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Heidelberg, Germany.
- Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany.
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14
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Barsoum M, Kusch S, Frantzeskakis L, Schaffrath U, Panstruga R. Ultraviolet Mutagenesis Coupled with Next-Generation Sequencing as a Method for Functional Interrogation of Powdery Mildew Genomes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:1008-1021. [PMID: 32370643 DOI: 10.1094/mpmi-02-20-0035-ta] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Powdery mildews are obligate biotrophic fungal pathogens causing important diseases of plants worldwide. Very little is known about the requirements for their pathogenicity at the molecular level. This is largely due to the inability to culture these organisms in vitro or to modify them genetically. Here, we describe a mutagenesis procedure based on ultraviolet (UV) irradiation to accumulate mutations in the haploid genome of the barley powdery mildew pathogen Blumeria graminis f. sp. hordei. Exposure of B. graminis f. sp. hordei conidia to different durations of UV-C radiation (10 s to 12 min) resulted in a reduced number of macroscopically visible fungal colonies. B. graminis f. sp. hordei colony number was negatively correlated with exposure time and the total number of consecutive cycles of UV irradiation. Dark incubation following UV exposure further reduced fungal viability, implying that photoreactivation is an important component of DNA repair in B. graminis f. sp. hordei. After several rounds of UV mutagenesis, we selected two mutant isolates in addition to the parental B. graminis f. sp. hordei K1 isolate for whole-genome resequencing. By combining automated prediction of sequence variants and their manual validation, we identified unique UV-induced mutations in the genomes of the two isolates. Most of these mutations were in the up- or downstream regions of genes or in the intergenic space. Some of the variants detected in genes led to predicted missense mutations. As an additional insight, our bioinformatic analyses revealed a complex population structure within supposedly clonal B. graminis f. sp. hordei isolates.
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Affiliation(s)
- Mirna Barsoum
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringerweg 1, 52056 Aachen, Germany
| | - Stefan Kusch
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringerweg 1, 52056 Aachen, Germany
| | - Lamprinos Frantzeskakis
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringerweg 1, 52056 Aachen, Germany
| | - Ulrich Schaffrath
- RWTH Aachen University, Institute for Biology III, Worringerweg 1, 52056 Aachen, Germany
| | - Ralph Panstruga
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringerweg 1, 52056 Aachen, Germany
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15
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Abstract
The genomes of bacteria contain fewer genes and substantially less noncoding DNA than those of eukaryotes, and as a result, they have much less raw material to invent new traits. Yet, bacteria are vastly more taxonomically diverse, numerically abundant, and globally successful in colonizing new habitats compared to eukaryotes. Although bacterial genomes are generally considered to be optimized for efficient growth and rapid adaptation, nonadaptive processes have played a major role in shaping the size, contents, and compact organization of bacterial genomes and have allowed the establishment of deleterious traits that serve as the raw materials for genetic innovation.
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Affiliation(s)
- Paul C Kirchberger
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA; ; ;
| | - Marian L Schmidt
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA; ; ;
| | - Howard Ochman
- Department of Integrative Biology, University of Texas at Austin, Texas 78712, USA; ; ;
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16
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Bobay LM. CoreSimul: a forward-in-time simulator of genome evolution for prokaryotes modeling homologous recombination. BMC Bioinformatics 2020; 21:264. [PMID: 32580695 PMCID: PMC7315543 DOI: 10.1186/s12859-020-03619-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/19/2020] [Indexed: 12/26/2022] Open
Abstract
Background Prokaryotes are asexual, but these organisms frequently engage in homologous recombination, a process that differs from meiotic recombination in sexual organisms. Most tools developed to simulate genome evolution either assume sexual reproduction or the complete absence of DNA flux in the population. As a result, very few simulators are adapted to model prokaryotic genome evolution while accounting for recombination. Moreover, many simulators are based on the coalescent, which assumes a neutral model of genomic evolution, and those are best suited for organisms evolving under weak selective pressures, such as animals and plants. In contrast, prokaryotes are thought to be evolving under much stronger selective pressures, suggesting that forward-in-time simulators are better suited for these organisms. Results Here, I present CoreSimul, a forward-in-time simulator of core genome evolution for prokaryotes modeling homologous recombination. Simulations are guided by a phylogenetic tree and incorporate different substitution models, including models of codon selection. Conclusions CoreSimul is a flexible forward-in-time simulator that constitutes a significant addition to the limited list of available simulators applicable to prokaryote genome evolution.
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Affiliation(s)
- Louis-Marie Bobay
- Department of Biology, University of North Carolina Greensboro, 321 McIver Street, PO Box 26170, Greensboro, NC, 27402, USA.
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17
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Skuce R, Breadon E, Allen A, Milne G, McCormick C, Hughes C, Rutherford D, Smith G, Thompson S, Graham J, Harwood R, Byrne A. Longitudinal dynamics of herd-level Mycobacterium bovis MLVA type surveillance in cattle in Northern Ireland 2003-2016. INFECTION GENETICS AND EVOLUTION 2019; 79:104131. [PMID: 31786341 DOI: 10.1016/j.meegid.2019.104131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/28/2019] [Accepted: 11/27/2019] [Indexed: 02/02/2023]
Abstract
Investigating genetically-structured diversity in pathogen populations over time is important to better understand disease maintenance and spread. Herd-level surveillance of Mycobacterium bovis genotypes (multi-locus VNTR analysis types, MLVA types) from all culture-confirmed bovine tuberculosis (TB) herd cases was undertaken in Northern Ireland (NI), generating an unparalleled, longitudinal, population-level 14-year survey for this pathogen. Across this population, 295 genetically-distinct M. bovis MLVA types were identified in the 19,717 M. bovis isolates surveyed. Of these, the most frequent was MLVA type 002 (23.0%); 151 MLVA types were represented more than once, in groups ranging from 2 to 4438 isolates. Only 23 MLVA types were isolated in all 14 years. Investigating inter-annual frequency of M. bovis MLVA types, examples of statistically-significant expansions (MLVA types 002, 004, 006, 009 and 027), contractions (MLVA types 001, 007 and 011) and maintenance (MLVA types 003 and 005) were disclosed, during a period of fluctuating bovine TB herd-level incidence at the NI scale. The fixed period frequency distribution of MLVA types remained highly right-skewed. Novel VNTR copy number variant MLVA types (N = 242; an average of 17 per annum) were identified throughout the survey. The MLVA type distribution in the landscape was not random; MLVA types showed statistically-significant geographical localization and strong spatial associations with Divisional Veterinary Office (DVO) regions. There was also evidence of differential risk of particular MLVA types across breeds (Holstein/Friesian vs. other), age-class, and sex and some evidence of an association between the number of animals testing positive for bovine TB during the disclosing test and particular MLVA types, although there was substantial variation.
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Affiliation(s)
- R Skuce
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK; School of Biological Sciences, Queen's University Belfast, Belfast BT7 1NN, UK.
| | - E Breadon
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - A Allen
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - G Milne
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - C McCormick
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK; Veterinary Service and Animal Health Group, Department of Agriculture, Environment and Rural Affairs, Dundonald House, Stormont, Belfast BT4 3SB, UK
| | - C Hughes
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - D Rutherford
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK; Faculty of Electrical Engineering, Czech Technical University, Prague, Czech Republic (⁎)current address
| | - G Smith
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - S Thompson
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - J Graham
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK
| | - R Harwood
- Veterinary Service and Animal Health Group, Department of Agriculture, Environment and Rural Affairs, Dundonald House, Stormont, Belfast BT4 3SB, UK
| | - A Byrne
- Veterinary Sciences Division, Agri-food and Biosciences Institute (AFBI), Stoney Road, Stormont, Belfast BT4 3SD, UK; School of Biological Sciences, Queen's University Belfast, Belfast BT7 1NN, UK; One-Health Unit, Surveillance, Animal By-Products and TSEs (SAT), Division Department of Agriculture, Food and Marine (DAFM), Agriculture House, Dublin 2, Ireland
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18
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Frazão N, Sousa A, Lässig M, Gordo I. Horizontal gene transfer overrides mutation in Escherichia coli colonizing the mammalian gut. Proc Natl Acad Sci U S A 2019; 116:17906-17915. [PMID: 31431529 PMCID: PMC6731689 DOI: 10.1073/pnas.1906958116] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Bacteria evolve by mutation accumulation in laboratory experiments, but tempo and mode of evolution in natural environments are largely unknown. Here, we study the ubiquitous natural process of host colonization by commensal bacteria. We show, by experimental evolution of Escherichia coli in the mouse intestine, that the ecology of the gut controls the pace and mode of evolution of a new invading bacterial strain. If a resident E. coli strain is present in the gut, the invading strain evolves by rapid horizontal gene transfer (HGT), which precedes and outweighs evolution by accumulation of mutations. HGT is driven by 2 bacteriophages carried by the resident strain, which cause an epidemic phage infection of the invader. These dynamics are followed by subsequent evolution by clonal interference of genetically diverse lineages of phage-carrying (lysogenic) bacteria. We show that the genes uptaken by HGT enhance the metabolism of specific gut carbon sources and provide a fitness advantage to lysogenic invader lineages. A minimal dynamical model explains the temporal pattern of phage epidemics and the complex evolutionary outcome of phage-mediated selection. We conclude that phage-driven HGT is a key eco-evolutionary driving force of gut colonization-it accelerates evolution and promotes genetic diversity of commensal bacteria.
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Affiliation(s)
- Nelson Frazão
- Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal
| | - Ana Sousa
- Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal
| | - Michael Lässig
- Institute for Biological Physics, University of Cologne, 50923 Cologne, Germany
| | - Isabel Gordo
- Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal;
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19
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Québatte M, Dehio C. Bartonella gene transfer agent: Evolution, function, and proposed role in host adaptation. Cell Microbiol 2019; 21:e13068. [PMID: 31231937 PMCID: PMC6899734 DOI: 10.1111/cmi.13068] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/09/2019] [Accepted: 06/13/2019] [Indexed: 01/05/2023]
Abstract
The processes underlying host adaptation by bacterial pathogens remain a fundamental question with relevant clinical, ecological, and evolutionary implications. Zoonotic pathogens of the genus Bartonella constitute an exceptional model to study these aspects. Bartonellae have undergone a spectacular diversification into multiple species resulting from adaptive radiation. Specific adaptations of a complex facultative intracellular lifestyle have enabled the colonisation of distinct mammalian reservoir hosts. This remarkable host adaptability has a multifactorial basis and is thought to be driven by horizontal gene transfer (HGT) and recombination among a limited genus‐specific pan genome. Recent functional and evolutionary studies revealed that the conserved Bartonella gene transfer agent (BaGTA) mediates highly efficient HGT and could thus drive this evolution. Here, we review the recent progress made towards understanding BaGTA evolution, function, and its role in the evolution and pathogenesis of Bartonella spp. We notably discuss how BaGTA could have contributed to genome diversification through recombination of beneficial traits that underlie host adaptability. We further address how BaGTA may counter the accumulation of deleterious mutations in clonal populations (Muller's ratchet), which are expected to occur through the recurrent transmission bottlenecks during the complex infection cycle of these pathogens in their mammalian reservoir hosts and arthropod vectors.
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20
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Shoemaker WR, Lennon JT. Evolution with a seed bank: The population genetic consequences of microbial dormancy. Evol Appl 2018; 11:60-75. [PMID: 29302272 PMCID: PMC5748526 DOI: 10.1111/eva.12557] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 09/08/2017] [Indexed: 12/31/2022] Open
Abstract
Dormancy is a bet‐hedging strategy that allows organisms to persist through conditions that are suboptimal for growth and reproduction by entering a reversible state of reduced metabolic activity. Dormancy allows a population to maintain a reservoir of genetic and phenotypic diversity (i.e., a seed bank) that can contribute to the long‐term survival of a population. This strategy can be potentially adaptive and has long been of interest to ecologists and evolutionary biologists. However, comparatively little is known about how dormancy influences the fundamental evolutionary forces of genetic drift, mutation, selection, recombination, and gene flow. Here, we investigate how seed banks affect the processes underpinning evolution by reviewing existing theory, implementing novel simulations, and determining how and when dormancy can influence evolution as a population genetic process. We extend our analysis to examine how seed banks can alter macroevolutionary processes, including rates of speciation and extinction. Through the lens of population genetic theory, we can understand the extent that seed banks influence the evolutionary dynamics of microorganisms as well as other taxa.
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Affiliation(s)
| | - Jay T Lennon
- Department of Biology Indiana University Bloomington IN USA
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21
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Abstract
The mutational process in bacteria is biased toward A and T, and most species are GC-rich relative to the mutational input to their genome. It has been proposed that the shift in base composition is an adaptive process-that natural selection operates to increase GC-contents-and there is experimental evidence that bacterial strains with GC-rich versions of genes have higher growth rates than those strains with AT-rich versions expressing identical proteins. Alternatively, a nonadaptive process, GC-biased gene conversion (gBGC), could also increase the GC-content of DNA due to the mechanistic bias of gene conversion events during recombination. To determine what role recombination plays in the base composition of bacterial genomes, we compared the spectrum of nucleotide polymorphisms introduced by recombination in all microbial species represented by large numbers of sequenced strains. We found that recombinant alleles are consistently biased toward A and T, and that the magnitude of AT-bias introduced by recombination is similar to that of mutations. These results indicate that recombination alone, without the intervention of selection, is unlikely to counteract the AT-enrichment of bacterial genomes.
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Affiliation(s)
- Louis-Marie Bobay
- Department of Integrative Biology, University of Texas at Austin, Austin, TX
| | - Howard Ochman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX
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22
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Chu HY, Sprouffske K, Wagner A. The role of recombination in evolutionary adaptation of Escherichia coli to a novel nutrient. J Evol Biol 2017; 30:1692-1711. [PMID: 28612351 DOI: 10.1111/jeb.13132] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/11/2017] [Accepted: 06/05/2017] [Indexed: 12/11/2022]
Abstract
The benefits and detriments of recombination for adaptive evolution have been studied both theoretically and experimentally, with conflicting predictions and observations. Most pertinent experiments examine recombination's effects in an unchanging environment and do not study its genomewide effects. Here, we evolved six replicate populations of either highly recombining R+ or lowly recombining R- E. coli strains in a changing environment, by introducing the novel nutrients L-arabinose or indole into the environment. The experiment's ancestral strains are not viable on these nutrients, but 130 generations of adaptive evolution were sufficient to render them viable. Recombination conferred a more pronounced advantage to populations adapting to indole. To study the genomic changes associated with this advantage, we sequenced the genomes of 384 clones isolated from selected replicates at the end of the experiment. These genomes harbour complex changes that range from point mutations to large-scale DNA amplifications. Among several candidate adaptive mutations, those in the tryptophanase regulator tnaC stand out, because the tna operon in which it resides has a known role in indole metabolism. One of the highly recombining populations also shows a significant excess of large-scale segmental DNA amplifications that include the tna operon. This lineage also shows a unique and potentially adaptive combination of point mutations and DNA amplifications that may have originated independently from one another, to be joined later by recombination. Our data illustrate that the advantages of recombination for adaptive evolution strongly depend on the environment and that they can be associated with complex genomic changes.
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Affiliation(s)
- H-Y Chu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - K Sprouffske
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - A Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,The Swiss Institute of Bioinformatics, Quartier Sorge, Batiment Genopode, Lausanne, Switzerland.,The Santa Fe Institute, Santa Fe, NM, USA
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23
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Bobay LM, Ochman H. Biological species are universal across Life's domains. Genome Biol Evol 2017; 9:2982379. [PMID: 28186559 PMCID: PMC5381558 DOI: 10.1093/gbe/evx026] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/31/2017] [Accepted: 02/06/2017] [Indexed: 12/19/2022] Open
Abstract
Delineation of species is fundamental to organizing and understanding biological diversity. The most widely applied criterion for distinguishing species is the Biological Species Concept (BSC), which defines species as groups of interbreeding individuals that remain reproductively isolated from other such groups. The BSC has broad appeal; however, many organisms, most notably asexual lineages, cannot be classified according to the BSC. Despite their exclusively asexual mode of reproduction, Bacteria and Archaea can transfer and exchange genes though homologous recombination. Here we show that barriers to homologous gene exchange define biological species in prokaryotes with the same efficacy as in sexual eukaryotes. By analyzing the impact of recombination on the polymorphisms in thousands of genome sequences, we find that over half of named bacterial species undergo continuous recombination among sequenced constituents, indicative of true biological species. However, nearly a quarter of named bacterial species show sharp discontinuities and comprise multiple biological species. These interruptions of gene flow are not a simple function of genome identity, indicating that bacterial speciation does not uniformly proceed by the gradual divergence of genome sequences. The same genomic approach based on recombinant polymorphisms retrieves known species boundaries in sexually reproducing eukaryotes. Thus, a single biological species definition based on gene flow, once thought to be limited only to sexually reproducing organisms, is applicable to all cellular lifeforms.
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Affiliation(s)
| | - Howard Ochman
- Department of Integrative Biology, University of Texas at Austin
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24
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Tibayrenc M, Ayala FJ. Is Predominant Clonal Evolution a Common Evolutionary Adaptation to Parasitism in Pathogenic Parasitic Protozoa, Fungi, Bacteria, and Viruses? ADVANCES IN PARASITOLOGY 2016; 97:243-325. [PMID: 28325372 DOI: 10.1016/bs.apar.2016.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We propose that predominant clonal evolution (PCE) in microbial pathogens be defined as restrained recombination on an evolutionary scale, with genetic exchange scarce enough to not break the prevalent pattern of clonal population structure. The main features of PCE are (1) strong linkage disequilibrium, (2) the widespread occurrence of stable genetic clusters blurred by occasional bouts of genetic exchange ('near-clades'), (3) the existence of a "clonality threshold", beyond which recombination is efficiently countered by PCE, and near-clades irreversibly diverge. We hypothesize that the PCE features are not mainly due to natural selection but also chiefly originate from in-built genetic properties of pathogens. We show that the PCE model obtains even in microbes that have been considered as 'highly recombining', such as Neisseria meningitidis, and that some clonality features are observed even in Plasmodium, which has been long described as panmictic. Lastly, we provide evidence that PCE features are also observed in viruses, taking into account their extremely fast genetic turnover. The PCE model provides a convenient population genetic framework for any kind of micropathogen. It makes it possible to describe convenient units of analysis (clones and near-clades) for all applied studies. Due to PCE features, these units of analysis are stable in space and time, and clearly delimited. The PCE model opens up the possibility of revisiting the problem of species definition in these organisms. We hypothesize that PCE constitutes a major evolutionary strategy for protozoa, fungi, bacteria, and viruses to adapt to parasitism.
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Affiliation(s)
- M Tibayrenc
- Institut de Recherche pour le Développement, Montpellier, France
| | - F J Ayala
- University of California at Irvine, United States
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25
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Transcriptome Remodeling Contributes to Epidemic Disease Caused by the Human Pathogen Streptococcus pyogenes. mBio 2016; 7:mBio.00403-16. [PMID: 27247229 PMCID: PMC4895104 DOI: 10.1128/mbio.00403-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
For over a century, a fundamental objective in infection biology research has been to understand the molecular processes contributing to the origin and perpetuation of epidemics. Divergent hypotheses have emerged concerning the extent to which environmental events or pathogen evolution dominates in these processes. Remarkably few studies bear on this important issue. Based on population pathogenomic analysis of 1,200 Streptococcus pyogenes type emm89 infection isolates, we report that a series of horizontal gene transfer events produced a new pathogenic genotype with increased ability to cause infection, leading to an epidemic wave of disease on at least two continents. In the aggregate, these and other genetic changes substantially remodeled the transcriptomes of the evolved progeny, causing extensive differential expression of virulence genes and altered pathogen-host interaction, including enhanced immune evasion. Our findings delineate the precise molecular genetic changes that occurred and enhance our understanding of the evolutionary processes that contribute to the emergence and persistence of epidemically successful pathogen clones. The data have significant implications for understanding bacterial epidemics and for translational research efforts to blunt their detrimental effects. The confluence of studies of molecular events underlying pathogen strain emergence, evolutionary genetic processes mediating altered virulence, and epidemics is in its infancy. Although understanding these events is necessary to develop new or improved strategies to protect health, surprisingly few studies have addressed this issue, in particular, at the comprehensive population genomic level. Herein we establish that substantial remodeling of the transcriptome of the human-specific pathogen Streptococcus pyogenes by horizontal gene flow and other evolutionary genetic changes is a central factor in precipitating and perpetuating epidemic disease. The data unambiguously show that the key outcome of these molecular events is evolution of a new, more virulent pathogenic genotype. Our findings provide new understanding of epidemic disease.
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Lapierre M, Blin C, Lambert A, Achaz G, Rocha EPC. The Impact of Selection, Gene Conversion, and Biased Sampling on the Assessment of Microbial Demography. Mol Biol Evol 2016; 33:1711-25. [PMID: 26931140 PMCID: PMC4915353 DOI: 10.1093/molbev/msw048] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Recent studies have linked demographic changes and epidemiological patterns in bacterial populations using coalescent-based approaches. We identified 26 studies using skyline plots and found that 21 inferred overall population expansion. This surprising result led us to analyze the impact of natural selection, recombination (gene conversion), and sampling biases on demographic inference using skyline plots and site frequency spectra (SFS). Forward simulations based on biologically relevant parameters from Escherichia coli populations showed that theoretical arguments on the detrimental impact of recombination and especially natural selection on the reconstructed genealogies cannot be ignored in practice. In fact, both processes systematically lead to spurious interpretations of population expansion in skyline plots (and in SFS for selection). Weak purifying selection, and especially positive selection, had important effects on skyline plots, showing patterns akin to those of population expansions. State-of-the-art techniques to remove recombination further amplified these biases. We simulated three common sampling biases in microbiological research: uniform, clustered, and mixed sampling. Alone, or together with recombination and selection, they further mislead demographic inferences producing almost any possible skyline shape or SFS. Interestingly, sampling sub-populations also affected skyline plots and SFS, because the coalescent rates of populations and their sub-populations had different distributions. This study suggests that extreme caution is needed to infer demographic changes solely based on reconstructed genealogies. We suggest that the development of novel sampling strategies and the joint analyzes of diverse population genetic methods are strictly necessary to estimate demographic changes in populations where selection, recombination, and biased sampling are present.
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Affiliation(s)
- Marguerite Lapierre
- Atelier de Bioinformatique, UMR7205 ISYEB, MNHN-UPMC-CNRS-EPHE, Muséum National d'Histoire Naturelle, Paris, France Collège de France, Center for Interdisciplinary Research in Biology (CIRB), CNRS UMR 7241, Paris, France
| | - Camille Blin
- Sorbonne Universités, UPMC Univ Paris06, IFD, 4 Place Jussieu, Paris Cedex05, France Institut Pasteur, Microbial Evolutionary Genomics, Paris, France CNRS, UMR3525, Paris, France
| | - Amaury Lambert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), CNRS UMR 7241, Paris, France UPMC Univ Paris 06, Laboratoire de Probabilités et Modèles Aléatoires (LPMA), CNRS UMR 7599, Paris, France
| | - Guillaume Achaz
- Atelier de Bioinformatique, UMR7205 ISYEB, MNHN-UPMC-CNRS-EPHE, Muséum National d'Histoire Naturelle, Paris, France Collège de France, Center for Interdisciplinary Research in Biology (CIRB), CNRS UMR 7241, Paris, France
| | - Eduardo P C Rocha
- Institut Pasteur, Microbial Evolutionary Genomics, Paris, France CNRS, UMR3525, Paris, France
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Maddamsetti R. Gene flow in microbial communities could explain unexpected patterns of synonymous variation in the Escherichia coli core genome. Mob Genet Elements 2016; 6:e1137380. [PMID: 27066306 PMCID: PMC4802760 DOI: 10.1080/2159256x.2015.1137380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 12/20/2015] [Accepted: 12/22/2015] [Indexed: 11/27/2022] Open
Abstract
Researchers contest the importance of gene flow in bacterial core genomes, as traditionalists view microbes as predominantly clonal, asexually reproducing organisms. Contrary to the traditional perspective, Escherichia coli core genes vary greatly in their levels of synonymous genetic diversity. This observation indicates that the relative importance of evolutionary forces such as mutation, selection, and recombination varies from gene to gene. In this paper, I highlight why the synonymous diversity observation is broadly relevant to researchers interested in the evolutionary dynamics of microbial populations and communities. I explain how a model of evolution called the coalescent relates neutral diversity (i.e. mutations with negligible fitness effects) to mutation rates, evolutionary time, and a parameter called effective population size. I then describe the possible ways in which mutation, selection, and recombination can explain observed patterns of synonymous diversity in E. coli. Finally, I describe a model for E. coli genome evolution in which different loci are subject to varying levels of gene flow among co-occurring microbes and viruses in the environment. Researchers can falsify the gene flow hypothesis by sequencing genes and strains isolated from stable microbiomes or by carrying out evolution experiments that trace gene genealogies in real-time.
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Affiliation(s)
- Rohan Maddamsetti
- Department of Integrative Biology, Michigan State University, East Lansing, MI, USA; Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI, USA; BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA
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