scholarly journals A new nomenclature for the livestock-associated Mycobacterium tuberculosis complex based on phylogenomics

2021 ◽  
Vol 1 ◽  
pp. 100
Author(s):  
Michaela Zwyer ◽  
Cengiz Çavusoglu ◽  
Giovanni Ghielmetti ◽  
Maria Lodovica Pacciarini ◽  
Erika Scaltriti ◽  
...  

Background The bacteria that compose the Mycobacterium tuberculosis complex (MTBC) cause tuberculosis (TB) in humans and in different animals, including livestock. Much progress has been made in understanding the population structure of the human-adapted members of the MTBC by combining phylogenetics with genomics. Accompanying the discovery of new genetic diversity, a body of operational nomenclature has evolved to assist comparative and molecular epidemiological studies of human TB. By contrast, for the livestock-associated MTBC members, Mycobacterium bovis, M. caprae and M. orygis, there has been a lack of comprehensive nomenclature to accommodate new genetic diversity uncovered by emerging phylogenomic studies. We propose to fill this gap by putting forward a new nomenclature covering the main phylogenetic groups within M. bovis, M. caprae and M. orygis. Methods We gathered a total of 8,736 whole-genome sequences (WGS) from public sources and 39 newly sequenced strains, and selected a subset of 829 WGS, representative of the worldwide diversity of M. bovis, M. caprae and M. orygis. We used phylogenetics and genetic diversity patterns inferred from WGS to define groups. Results We propose to divide M. bovis, M. caprae and M. orygis in three main phylogenetic lineages, which we named La1, La2 and La3, respectively. Within La1, we identified several monophyletic groups, which we propose to classify into eight sublineages (La1.1-La1.8). These sublineages differed in geographic distribution, with some being geographically restricted and others globally widespread, suggesting different expansion abilities. To ease molecular characterization of these MTBC groups by the community, we provide phylogenetically informed, single nucleotide polymorphisms that can be used as barcodes for genotyping. These markers were implemented in KvarQ and TB-Profiler, which are platform-independent, open-source tools. Conclusions Our results contribute to an improved classification of the genetic diversity within the livestock-associated MTBC, which will benefit future molecular epidemiological and evolutionary studies.

2021 ◽  
Vol 1 ◽  
pp. 100
Author(s):  
Michaela Zwyer ◽  
Cavusoglu Cengiz ◽  
Giovanni Ghielmetti ◽  
Maria Lodovica Pacciarini ◽  
Erika Scaltriti ◽  
...  

Background The bacteria that compose the Mycobacterium tuberculosis complex (MTBC) cause tuberculosis (TB) in humans and in different animals, including livestock. Much progress has been made in understanding the population structure of the human-adapted members of the MTBC by combining phylogenetics with genomics. Accompanying the discovery of new genetic diversity, a body of operational nomenclature has evolved to assist comparative and molecular epidemiological studies of human TB. By contrast, for the livestock-associated MTBC members, Mycobacterium bovis, M. caprae and M. orygis, there has been a lack of comprehensive nomenclature to accommodate new genetic diversity uncovered by emerging phylogenomic studies. We propose to fill this gap by putting forward a new nomenclature covering the main phylogenetic groups within M. bovis, M. caprae and M. orygis. Methods We gathered a total of 8,747 whole-genome sequences (WGS) from public sources and 39 newly sequenced strains, and selected a subset of 839 WGS, representative of the worldwide diversity of M. bovis, M. caprae and M. orygis. We used phylogenetics and genetic diversity patterns inferred from WGS to define groups. Results We propose to divide M. bovis, M. caprae and M. orygis, in three main phylogenetic lineages, which we named La1, La2 and La3, respectively. Within La1, we identified several monophyletic groups, which we propose to classify into eight sublineages (La1.1-La1.8). These differed in geographic distribution, with some being geographically restricted and others globally widespread, suggesting different expansion abilities. To ease molecular characterization of these MTBC groups by the community, we provide phylogenetically informed, single nucleotide polymorphisms that can be used as barcodes for genotyping. These makers were implemented in a new test suit in KvarQ, a platform-independent, open-source tool. Conclusions Our results contribute to an improved classification of the genetic diversity within the livestock-associated MTBC, which will benefit future molecular epidemiological and evolutionary studies.


2005 ◽  
Vol 71 (12) ◽  
pp. 8207-8213 ◽  
Author(s):  
Andrea Gibson ◽  
Timothy Brown ◽  
Lucy Baker ◽  
Francis Drobniewski

ABSTRACT The phylogeny and evolution of the bacterium Mycobacterium tuberculosis is still poorly understood despite the application of a variety of molecular techniques. We analyzed 469 M. tuberculosis and 49 Mycobacterium bovis isolates to evaluate if the mycobacterial interspersed repetitive units-variable-number tandem repeats (MIRU-VNTR) commonly used for epidemiological studies can define the phylogeny of the M. tuberculosis complex. This population was characterized by previously identified silent single-nucleotide polymorphisms (sSNPs) or by a macroarray based on these sSNPs that was developed in this study. MIRU-VNTR phylogenetic codes capable of differentiating between phylogenetic lineages were identified. Overall, there was 90.9% concordance between the lineages of isolates as defined by the MIRU-VNTR and sSNP analyses. The MIRU-VNTR phylogenetic code was unique to M. bovis and was not observed in any M. tuberculosis isolates. The codes were able to differentiate between different M. tuberculosis strain families such as Beijing, Delhi, and East African-Indian. Discrepant isolates with similar but not identical MIRU-VNTR codes often displayed a stepwise trend suggestive of bidirectional evolution. A lineage-specific panel of MIRU-VNTR can be used to subdivide each lineage for epidemiological purposes. MIRU-VNTR is a valuable tool for phylogenetic studies and could define an evolutionarily uncharacterized population of M. tuberculosis complex organisms.


2018 ◽  
Vol 69 (2) ◽  
pp. 73-83 ◽  
Author(s):  
Gábor Mészáros

Summary The characterization of livestock genetic diversity has experienced extensive changes with the availability of dense nucleotide markers. Among the various forms of markers, the single nucleotide polymorphisms (SNP) have arguably the largest influence. A wide range of indicators for the assessment of genetic diversity was developed, or the existing methods were improved, enabling us to make informed decisions on the management of livestock populations. This review discusses the selected aspects of diversity assessment, with special attention to the SNP based methods. One of the core concepts in genomics of diversity is the linkage disequilibrium (LD), as it was shaped by demographic events during the development of breeds and species. These events, either natural or artificial, left detectable signals within the livestock genomes. Further changes were induced by human activity when mating related animals, leading to fixing or improving the desired traits in the breed, but reducing their genetic variability. The assessment of relatedness is also pivotal to construct meaningful mating plans and to avoid the negative consequences of inbreeding depression that might be detrimental especially in small, endangered populations. Both LD and relatedness are of interest on their own, as well as in their follow-up applications deriving overall measures of effective population size.


2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Ashleigh Cheyne ◽  
Agnieszka Broda ◽  
Nitya Krishnan ◽  
Brian Robertson ◽  
Myrsini Kaforou ◽  
...  

Despite being the number one cause of death from an infectious disease, little is known of the 7 phylogenetic lineages of Mycobacterium tuberculosis (Mtb). These lineages are thought to have adapted differently to their human hosts, as they are geographically localised. As a result, they show variation at the phenotype level, such as virulence and the ability to develop antibiotic resistance, and at a genomic level, such as in single nucleotide polymorphisms (SNPs). We have linked the differences in SNPs between lineages to differences in metabolites (i.e. what is ultimately produced by a cell). Through multi-omic integration of these datasets we have discovered lineage-specific metabolomic changes, potentially as a result of genomic adaptation. The differences between lineages will provide insight into new biological pathways to target and manipulate in future research.


2018 ◽  
Author(s):  
Liliana K. Rutaihwa ◽  
Mohamed Sasamalo ◽  
Aladino Jaleco ◽  
Jerry Hella ◽  
Ally Kingazi ◽  
...  

AbstractBackgroundHuman tuberculosis (TB) is caused by seven phylogenetic lineages of theMycobacterium tuberculosiscomplex (MTBC), Lineage 1–7. Recent advances in rapid genotyping of MTBC based on single nucleotide polymorphisms (SNP), allow for rapid and phylogenetically robust strain classification, paving the way for defining genotype-phenotype relationships in clinical settings. Such studies have revealed that, in addition to host and environmental factors, different strains of the MTBC influence the outcome of TB infection and disease. In Tanzania, such molecular epidemiological studies of TB however are scarce in spite of a high TB burden.Methods and FindingsHere we used a SNP-typing method to genotype a nationwide collection of 2,039 MTBC clinical isolates obtained from new and retreatment TB cases diagnosed in 2012 and 2013. Four lineages, namely Lineage 1–4 were identified. The distribution and frequency of these lineages varied across the regions but overall, Lineage 4 was the most frequent (n=866, 42.5%), followed by Lineage 3 (n=681, 33.4%) and 1 (n=336, 16.5%), with Lineage 2 being the least frequent (n=92, 4.5%). A total of 64 (3.1%) isolates could not be assigned to any lineage. We found Lineage 2 to be associated with female sex (adjusted odds ratio [aOR] 2.25; 95% confidence interval [95% CI] 1.38 – 3.70, p<0.001) and retreatment (aOR 1.78; 95% CI 1.00 – 3.02, p=0.040). We found no associations between MTBC lineage and patient age or HIV status. Our sublineage typing based on spacer oligotyping revealed the presence of mainly EAI, CAS and LAM families. Finally, we detected low levels of multidrug resistant isolates among a subset of retreatment casesConclusionsThis study provides novel insights into the influence of pathogen-related factors on the TB epidemic in Tanzania.


2014 ◽  
Vol 80 (14) ◽  
pp. 4398-4413 ◽  
Author(s):  
Sam Crauwels ◽  
Bo Zhu ◽  
Jan Steensels ◽  
Pieter Busschaert ◽  
Gorik De Samblanx ◽  
...  

ABSTRACTBrettanomycesyeasts, with the speciesBrettanomyces(Dekkera)bruxellensisbeing the most important one, are generally reported to be spoilage yeasts in the beer and wine industry due to the production of phenolic off flavors. However,B. bruxellensisis also known to be a beneficial contributor in certain fermentation processes, such as the production of certain specialty beers. Nevertheless, despite its economic importance,Brettanomycesyeasts remain poorly understood at the genetic and genomic levels. In this study, the genetic relationship between more than 50Brettanomycesstrains from all presently known species and from several sources was studied using a combination of DNA fingerprinting techniques. This revealed an intriguing correlation between theB. bruxellensisfingerprints and the respective isolation source. To further explore this relationship, we sequenced a (beneficial) beer isolate ofB. bruxellensis(VIB X9085; ST05.12/22) and compared its genome sequence with the genome sequences of two wine spoilage strains (AWRI 1499 and CBS 2499). ST05.12/22 was found to be substantially different from both wine strains, especially at the level of single nucleotide polymorphisms (SNPs). In addition, there were major differences in the genome structures between the strains investigated, including the presence of large duplications and deletions. Gene content analysis revealed the presence of 20 genes which were present in both wine strains but absent in the beer strain, including many genes involved in carbon and nitrogen metabolism, and vice versa, no genes that were missing in both AWRI 1499 and CBS 2499 were found in ST05.12/22. Together, this study provides tools to discriminateBrettanomycesstrains and provides a first glimpse at the genetic diversity and genome plasticity ofB. bruxellensis.


2015 ◽  
Author(s):  
Sanaa Afroz Ahmed ◽  
Chien-Chi Lo ◽  
Po-E Li ◽  
Karen W Davenport ◽  
Patrick S.G. Chain

Next-generation sequencing is increasingly being used to examine closely related organisms. However, while genome-wide single nucleotide polymorphisms (SNPs) provide an excellent resource for phylogenetic reconstruction, to date evolutionary analyses have been performed using different ad hoc methods that are not often widely applicable across different projects. To facilitate the construction of robust phylogenies, we have developed a method for genome-wide identification/characterization of SNPs from sequencing reads and genome assemblies. Our phylogenetic and molecular evolutionary (PhaME) analysis software is unique in its ability to take reads and draft/complete genome(s) as input, derive core genome alignments, identify SNPs, construct phylogenies and perform evolutionary analyses. Several examples using genomes and read datasets for bacterial, eukaryotic and viral linages demonstrate the broad and robust functionality of PhaME. Furthermore, the ability to incorporate raw metagenomic reads from clinical samples with suspected infectious agents shows promise for the rapid phylogenetic characterization of pathogens within complex samples.


2021 ◽  
Vol 118 (34) ◽  
pp. e2104315118
Author(s):  
Pasquale Tripodi ◽  
Mark Timothy Rabanus-Wallace ◽  
Lorenzo Barchi ◽  
Sandip Kale ◽  
Salvatore Esposito ◽  
...  

Genebanks collect and preserve vast collections of plants and detailed passport information, with the aim of preserving genetic diversity for conservation and breeding. Genetic characterization of such collections has the potential to elucidate the genetic histories of important crops, use marker–trait associations to identify loci controlling traits of interest, search for loci undergoing selection, and contribute to genebank management by identifying taxonomic misassignments and duplicates. We conducted a genomic scan with genotyping by sequencing (GBS) derived single nucleotide polymorphisms (SNPs) of 10,038 pepper (Capsicum spp.) accessions from worldwide genebanks and investigated the recent history of this iconic staple. Genomic data detected up to 1,618 duplicate accessions within and between genebanks and showed that taxonomic ambiguity and misclassification often involve interspecific hybrids that are difficult to classify morphologically. We deeply interrogated the genetic diversity of the commonly consumed Capsicum annuum to investigate its history, finding that the kinds of peppers collected in broad regions across the globe overlap considerably. The method ReMIXTURE—using genetic data to quantify the similarity between the complement of peppers from a focal region and those from other regions—was developed to supplement traditional population genetic analyses. The results reflect a vision of pepper as a highly desirable and tradable cultural commodity, spreading rapidly throughout the globe along major maritime and terrestrial trade routes. Marker associations and possible selective sweeps affecting traits such as pungency were observed, and these traits were shown to be distributed nonuniformly across the globe, suggesting that human preferences exerted a primary influence over domesticated pepper genetic structure.


2016 ◽  
Vol 141 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Michael J. Havey ◽  
Yul-Kyun Ahn

Garlic (Allium sativum) is cultivated worldwide and appreciated for its culinary uses. In spite of primarily being asexually propagated, garlic shows great morphological variation and adaptability to diverse production environments. Molecular markers and phenotypic characteristics have been used to assess the genetic diversity among garlics. In this study, we undertook transcriptome sequencing from a single garlic plant to identify molecular markers in expressed regions of the garlic genome. Garlic sequences were assembled and selected if they were similar to monomorphic sequences from a doubled haploid (DH) of onion (Allium cepa). Single nucleotide polymorphisms (SNPs) and insertion–deletion (indel) events were identified in 4355 independent garlic assemblies. A sample of the indels was verified using the original complementary DNA (cDNA) library and genomics DNAs from diverse garlics, and segregations confirmed by sexual progenies of garlic. These molecular markers from the garlic transcriptome should be useful for estimates of genetic diversity, identification and removal of duplicate accessions from germplasm collections, and the development of a detailed genetic map of this important vegetable crop.


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