Whole Genome Sequencing of Field Isolates Provides Robust Characterization of Genetic Diversity in Plasmodium vivax

AbstractThe use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Båven, Emån, and Möckeln) and one reintroduced population of admixed origin (Helge å), and found that genetic diversity was highest in Emån but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge å shared most genetic ancestry with the Båven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.

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SureSelect targeted enrichment, a new cost effective method for the whole genome sequencing of Candidatus Liberibacter asiaticus

Scientific Reports ◽

10.1038/s41598-019-55144-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Weili Cai ◽

Schyler Nunziata ◽

John Rascoe ◽

Michael J. Stulberg

Keyword(s):

Whole Genome Sequencing ◽

Molecular Characterization ◽

Genome Sequencing ◽

Whole Genome Sequence ◽

Whole Genome ◽

Genome Coverage ◽

Metagenomic Sample ◽

Liberibacter Asiaticus

AbstractHuanglongbing (HLB) is a worldwide deadly citrus disease caused by the phloem-limited bacteria ‘Candidatus Liberibacter asiaticus’ (CLas) vectored by Asian citrus psyllids. In order to effectively manage this disease, it is crucial to understand the relationship among the bacterial isolates from different geographical locations. Whole genome sequencing approaches will provide more precise molecular characterization of the diversity among populations. Due to the lack of in vitro culture, obtaining the whole genome sequence of CLas is still a challenge, especially for medium to low titer samples. Hundreds of millions of sequencing reads are needed to get good coverage of CLas from an HLB positive citrus sample. In order to overcome this limitation, we present here a new method, Agilent SureSelect XT HS target enrichment, which can specifically enrich CLas from a metagenomic sample while greatly reducing cost and increasing whole genome coverage of the pathogen. In this study, the CLas genome was successfully sequenced with 99.3% genome coverage and over 72X sequencing coverage from low titer tissue samples (equivalent to 28.52 Cq using Li 16 S qPCR). More importantly, this method also effectively captures regions of diversity in the CLas genome, which provides precise molecular characterization of different strains.

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A combination of metagenomic and cultivation approaches reveals hypermutator phenotypes within Vibrio cholerae infected patients

10.1101/2020.10.11.333682 ◽

2020 ◽

Author(s):

Inès Levade ◽

Ashraful I. Khan ◽

Fahima Chowdhury ◽

Stephen B. Calderwood ◽

Edward T. Ryan ◽

...

Keyword(s):

Genetic Diversity ◽

Whole Genome Sequencing ◽

Vibrio Cholerae ◽

Genome Sequencing ◽

Asymptomatic Infection ◽

Whole Genome ◽

Metagenomic Sequencing ◽

Asymptomatic Carriers ◽

Adaptive Mutations ◽

Neutral Mutations

ABSTRACTVibrio cholerae can cause a range of symptoms in infected patients, ranging from severe diarrhea to asymptomatic infection. Previous studies using whole genome sequencing (WGS) of multiple bacterial isolates per patient have shown that Vibrio cholerae can evolve a modest amount of genetic diversity during symptomatic infection. Little is known about V. cholerae genetic diversity within asymptomatic infected patients. To achieve increased resolution in the detection of Vibrio cholerae diversity within individual infections, we applied culture-based population genomics and metagenomics to a cohort of symptomatic and asymptomatic cholera patients. While the metagenomic approach allowed us to detect more mutations in symptomatic patients compared to the culture-based approach, WGS of isolates was still necessary to detect V. cholerae diversity in asymptomatic carriers, likely due to their low Vibrio cholerae load. We found that symptomatic and asymptomatic patients contain similar levels of within-patient diversity, and discovered V. cholerae hypermutators in some patients. While hypermutators appeared to generate mostly selectively neutral mutations, non-mutators showed signs of convergent mutation across multiple patients, suggesting V. cholerae adaptation within hosts. Our results highlight the power of metagenomics combined with isolate sequencing to characterize within-patient diversity in acute V. cholerae infection and asymptomatic infection, while providing evidence for hypermutator phenotypes within cholera patients.IMPORTANCEPathogen evolution within patients can impact phenotypes such as drug resistance and virulence, potentially affecting clinical outcomes. V. cholerae infection can result in life-threatening diarrheal disease, or asymptomatic infection. Here we describe whole-genome sequencing of V. cholerae isolates and culture-free metagenomic sequencing from stool of symptomatic cholera patients and asymptomatic carriers. Despite the acuteness of cholera infections, we found evidence for adaptive mutations in the V. cholerae genome that occur independently and repeatedly within multiple symptomatic patients. We also identified V. cholerae hypermutator phenotypes within 6 out of 14 patients, which appear to generate mainly neutral or deleterious mutations. Our work sets the stage for future studies of the role of hypermutators and within-patient evolution in explaining the variation from asymptomatic carriage to symptomatic cholera.

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First isolation and characterization of Brucella suis from yak

Genome ◽

10.1139/gen-2019-0101 ◽

2020 ◽

Vol 63 (8) ◽

pp. 397-405

Author(s):

Xiaowen Yang ◽

Ning Wang ◽

Xiaofang Cao ◽

Pengfei Bie ◽

Zhifeng Xing ◽

...

Keyword(s):

Whole Genome Sequencing ◽

Genome Sequencing ◽

Health And Safety ◽

Host Cells ◽

Whole Genome ◽

Genetic Characteristics ◽

Qinghai Province ◽

Isolation And Characterization ◽

Smooth Strain

Brucella spp., facultative intracellular pathogens that can persistently colonize animal host cells and cause zoonosis, affect public health and safety. A Brucella strain was isolated from yak in Qinghai Province. To detect whether this isolate could cause an outbreak of brucellosis and to reveal its genetic characteristics, several typing and whole-genome sequencing methods were applied to identify its species and genetic characteristics. Phylogenetic analysis based on MLVA and whole-genome sequencing revealed the genetic characteristics of the isolated strain. The results showed that the isolated strain is a B. suis biovar 1 smooth strain, and this isolate was named B. suis QH05. The results of comparative genomics and MLVA showed that B. suis QH05 is not a vaccine strain. Comparison with other B. suis strains isolated from humans and animals indicated that B. suis QH05 may be linked to specific animal and human sources. In conclusion, B. suis QH05 does not belong to the Brucella epidemic species in China, and as the first isolation of B. suis from yak, this strain expands the host range of B. suis.

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