Use of retrotransposon-derived genetic markers to analyse genomic variability in plants

2019 ◽  
Vol 46 (1) ◽  
pp. 15 ◽  
Author(s):  
Ruslan Kalendar ◽  
Asset Amenov ◽  
Asset Daniyarov
Keyword(s):  
Genetic Diversity ◽  
Digital Pcr ◽  
Genomic Variability ◽  
Plant Genomes ◽  
Anchored Pcr ◽  
Copy And Paste ◽  
Somatic Transposition ◽  
Replicative Transposition ◽  
Eukaryotic Genomes ◽  
Generation Sequencing

Transposable elements (TEs) are common mobile genetic elements comprising several classes and making up the majority of eukaryotic genomes. The movement and accumulation of TEs has been a major force shaping the genes and genomes of most organisms. Most eukaryotic genomes are dominated by retrotransposons and minimal DNA transposon accumulation. The ‘copy and paste’ lifecycle of replicative transposition produces new genome insertions without excising the original element. Horizontal TE transfer among lineages is rare. TEs represent a reservoir of potential genomic instability and RNA-level toxicity. Many TEs appear static and nonfunctional, but some are capable of replicating and mobilising to new positions, and somatic transposition events have been observed. The overall structure of retrotransposons and the domains responsible for the phases of their replication are highly conserved in all eukaryotes. TEs are important drivers of species diversity and exhibit great variety in their structure, size and transposition mechanisms, making them important putative actors in evolution. Because TEs are abundant in plant genomes, various applications have been developed to exploit polymorphisms in TE insertion patterns, including conventional or anchored PCR, and quantitative or digital PCR with primers for the 5ʹ or 3ʹ junction. Alternatively, the retrotransposon junction can be mapped using high-throughput next-generation sequencing and bioinformatics. With these applications, TE insertions can be rapidly, easily and accurately identified, or new TE insertions can be found. This review provides an overview of the TE-based applications developed for plant species and assesses the contributions of TEs to the analysis of plants’ genetic diversity.

Tc8, a Tourist-like Transposon in Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1081-1088 ◽  
Author(s):  
Quang Hien Le ◽  
Kime Turcotte ◽  
Thomas Bureau
Keyword(s):  
Caenorhabditis Elegans ◽  
Expressed Sequence Tags ◽  
Large Family ◽  
Insertion Sequences ◽  
Normal Plant ◽  
Nematode Caenorhabditis Elegans ◽  
Plant Genomes ◽  
Plant Genes ◽  
Expressed Sequence ◽  
Eukaryotic Genomes

Abstract Members of the Tourist family of miniature inverted-repeat transposable elements (MITEs) are very abundant among a wide variety of plants, are frequently found associated with normal plant genes, and thus are thought to be important players in the organization and evolution of plant genomes. In Arabidopsis, the recent discovery of a Tourist member harboring a putative transposase has shed new light on the mobility and evolution of MITEs. Here, we analyze a family of Tourist transposons endogenous to the genome of the nematode Caenorhabditis elegans (Bristol N2). One member of this large family is 7568 bp in length, harbors an ORF similar to the putative Tourist transposase from Arabidopsis, and is related to the IS5 family of bacterial insertion sequences (IS). Using database searches, we found expressed sequence tags (ESTs) similar to the putative Tourist transposases in plants, insects, and vertebrates. Taken together, our data suggest that Tourist-like and IS5-like transposons form a superfamily of potentially active elements ubiquitous to prokaryotic and eukaryotic genomes.

scholarly journals Development of KASP Markers for Germplasm Characterization and Fingerprinting Identification of Broccoli in China

2020 ◽  
Author(s):  
Yusen Shen ◽  
Jiansheng Wang ◽  
Huifang Yu ◽  
Xiaoguang Sheng ◽  
Zhenqing Zhao ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Marker Assisted Selection ◽  
Genetic Relationships ◽  
Cost Effective ◽  
Germplasm Characterization ◽  
2D Barcode ◽  
New Type ◽  
Generation Sequencing ◽  
Kasp Markers ◽  
Selection Of

Abstract Background: Broccoli (Brassica oleracea var. italica) is a vegetable widely cultivated in China. Many new-type broccoli cultivars were bred and developed by Chinese breeders during the recent three decades. However, the broccoli cultivar nomenclature and detailed information of genetic relationships among broccoli germplasms are unclear. Results: The present study identified millions of SNPs by next-generation sequencing of 23 representative broccoli lines. Through several steps of selection, 100 SNPs were successfully converted into KASP markers, and used to evaluate the genetic diversity, genetic relationship, and population structure of 392 broccoli accessions, which represent the mainly broccoli breeding materials in China. The initial, introduced and improved accessions were well clustered, though some accessions were overlapped between groups, probably reflecting the fact that breeding activities led to genetic similarities. To make the KASP genotyping more efficient and cost-effective, 25 of the 100 KASPs were selected for fingerprinting of all accessions, and the 2D barcode contained fingerprinting information were generated for elite varieties. Conclusion: The KASP markers developed in this study provided an efficient way for germplasm characterization, DNA fingerprinting, seed purity identification, and marker-assisted selection of broccoli in China.

scholarly journals A Comparison of Blood Pathogen Detection Among Droplet Digital PCR, Metagenomic Next-Generation Sequencing, and Blood Culture in Critically Ill Patients With Suspected Bloodstream Infections

2021 ◽  
Vol 12 ◽  
Author(s):  
Bangchuan Hu ◽  
Yue Tao ◽  
Ziqiang Shao ◽  
Yang Zheng ◽  
Run Zhang ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Blood Culture ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Pathogen Detection ◽  
Bloodstream Infections ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Next Generation ◽  
Generation Sequencing

Metagenomic next-generation sequencing (mNGS) and droplet digital PCR (ddPCR) have recently demonstrated a great potential for pathogen detection. However, few studies have been undertaken to compare these two nucleic acid detection methods for identifying pathogens in patients with bloodstream infections (BSIs). This prospective study was thus conducted to compare these two methods for diagnostic applications in a clinical setting for critically ill patients with suspected BSIs. Upon suspicion of BSIs, whole blood samples were simultaneously drawn for ddPCR covering 20 common isolated pathogens and four antimicrobial resistance (AMR) genes, mNGS, and blood culture. Then, a head-to-head comparison was performed between ddPCR and mNGS. A total of 60 episodes of suspected BSIs were investigated in 45 critically ill patients, and ddPCR was positive in 50 (83.3%), mNGS in 41 (68.3%, not including viruses), and blood culture in 10 (16.7%) episodes. Of the 10 positive blood cultures, nine were concordantly identified by both mNGS and ddPCR methods. The head-to-head comparison showed that ddPCR was more rapid (~4 h vs. ~2 days) and sensitive (88 vs. 53 detectable pathogens) than mNGS within the detection range of ddPCR, while mNGS detected a broader range of pathogens (126 vs. 88 detectable pathogens, including viruses) than ddPCR. In addition, a total of 17 AMR genes, including 14 blaKPC and 3 mecA genes, were exclusively identified by ddPCR. Based on their respective limitations and strengths, the ddPCR method is more useful for rapid detection of common isolated pathogens as well as AMR genes in critically ill patients with suspected BSI, whereas mNGS testing is more appropriate for the diagnosis of BSI where classic microbiological or molecular diagnostic approaches fail to identify causative pathogens.

scholarly journals Genome-wide analysis of ivermectin response by Onchocerca volvulus reveals that genetic drift and soft selective sweeps contribute to loss of drug sensitivity

2016 ◽  
Author(s):  
Stephen R. Doyle ◽  
Catherine Bourguinat ◽  
Hugues C. Nana-Djeunga ◽  
Jonas A. Kengne-Ouafo ◽  
Sébastien D.S. Pion ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Next Generation Sequencing ◽  
Genetic Drift ◽  
Onchocerca Volvulus ◽  
Molecular Pathways ◽  
Ivermectin Treatment ◽  
Genetic Changes ◽  
Genome Wide ◽  
Parasite Populations ◽  
Generation Sequencing

ABSTRACTBackgroundTreatment of onchocerciasis using mass ivermectin administration has reduced morbidity and transmission throughout Africa and Central/South America. Mass drug administration is likely to exert selection pressure on parasites, and phenotypic and genetic changes in several Onchocerca volvulus populations from Cameroon and Ghana - exposed to more than a decade of regular ivermectin treatment - have raised concern that sub-optimal responses to ivermectin’s anti-fecundity effect are becoming more frequent and may spread.Methodology/Principal FindingsPooled next generation sequencing (Pool-seq) was used to characterise genetic diversity within and between 108 adult female worms differing in ivermectin treatment history and response. Genome-wide analyses revealed genetic variation that significantly differentiated good responder (GR) and sub-optimal responder (SOR) parasites. These variants were not randomly distributed but clustered in ~31 quantitative trait loci (QTLs), with little overlap in putative QTL position and gene content between countries. Published candidate ivermectin SOR genes were largely absent in these regions; QTLs differentiating GR and SOR worms were enriched for genes in molecular pathways associated with neurotransmission, development, and stress responses. Finally, single worm genotyping demonstrated that geographic isolation and genetic change over time (in the presence of drug exposure) had a significantly greater role in shaping genetic diversity than the evolution of SOR.Conclusions/SignificanceThis study is one of the first genome-wide association analyses in a parasitic nematode, and provides insight into the genomics of ivermectin response and population structure of O. volvulus. We argue that ivermectin response is a polygenically-determined quantitative trait in which identical or related molecular pathways but not necessarily individual genes likely determine the extent of ivermectin response in different parasite populations. Furthermore, we propose that genetic drift rather than genetic selection of SOR is the underlying driver of population differentiation, which has significant implications for the emergence and potential spread of SOR within and between these parasite populations.Author summaryOnchocerciasis is a human parasitic disease endemic across large areas of Sub-Saharan Africa, where more that 99% of the estimated 100 million people globally at-risk live. The microfilarial stage of Onchocerca volvulus causes pathologies ranging from mild itching to visual impairment and ultimately, irreversible blindness. Mass administration of ivermectin kills microfilariae and has an anti-fecundity effect on adult worms by temporarily inhibiting the development in utero and/or release into the skin of new microfilariae, thereby reducing morbidity and transmission. Phenotypic and genetic changes in some parasite populations that have undergone multiple ivermectin treatments in Cameroon and Ghana have raised concern that sub-optimal response to ivermectin’s anti-fecundity effect may increase in frequency, reducing the impact of ivermectin-based control measures. We used next generation sequencing of small pools of parasites to define genome-wide genetic differences between phenotypically characterised good and sub-optimal responder parasites from Cameroon and Ghana, and identified multiple genomic regions differentiating the response types. These regions were largely different between parasites from both countries but revealed common molecular pathways that might be involved in determining the extent of response to ivermectin’s anti-fecundity effect. These data reveal a more complex than previously described pattern of genetic diversity among O. volvulus populations that differ in their geography and response to ivermectin treatment.

Genetic diversity of Hepatitis C Virus in Pakistan using Next Generation Sequencing

2018 ◽  
Vol 108 ◽  
pp. 26-31 ◽  
Author(s):  
Sana Saleem ◽  
Amjad Ali ◽  
Bushra Khubaib ◽  
Madiha Akram ◽  
Zareen Fatima ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Next Generation Sequencing ◽  
Next Generation ◽  
Generation Sequencing

scholarly journals Digital PCR—An Emerging Technology with Broad Applications in Microbiology

2019 ◽  
Vol 66 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Stephen J Salipante ◽  
Keith R Jerome
Keyword(s):  
Next Generation Sequencing ◽  
Quantitative Pcr ◽  
Clinical Microbiology ◽  
Clinical Laboratory ◽  
Digital Pcr ◽  
Emerging Technology ◽  
Next Generation ◽  
Powerful Technique ◽  
Advantages And Disadvantages ◽  
Generation Sequencing

Abstract BACKGROUND The PCR and its variant, quantitative PCR (qPCR), have revolutionized the practice of clinical microbiology. Continued advancements in PCR have led to a new derivative, digital PCR (dPCR), which promises to address certain limitations inherent to qPCR. CONTENT Here we highlight the important technical differences between qPCR and dPCR, and the potential advantages and disadvantages of each. We then review specific situations in which dPCR has been implemented in clinical microbiology and the results of such applications. Finally, we attempt to place dPCR in the context of other emerging technologies relevant to the clinical laboratory, including next-generation sequencing. SUMMARY dPCR offers certain clear advantages over traditional qPCR, but these are to some degree offset by limitations of the technology, at least as currently practiced. Laboratories considering implementation of dPCR should carefully weigh the potential advantages and disadvantages of this powerful technique for each specific application planned.

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