Secure and Verifiable Outsourcing of Sequence Comparisons

The genus Dichorhavirus contains viruses with bipartite, negative-sense, single-stranded RNA genomes that are transmitted by flat mites to hosts that include orchids, coffee, the genus Clerodendrum, and citrus. A dichorhavirus infecting citrus in Mexico is classified as a citrus strain of orchid fleck virus (OFV-Cit). We previously used RNA sequencing technologies on OFV-Cit samples from Mexico to develop an OFV-Cit–specific reverse transcription PCR (RT-PCR) assay. During assay validation, OFV-Cit–specific RT-PCR failed to produce an amplicon from some samples with clear symptoms of OFV-Cit. Characterization of this virus revealed that dichorhavirus-like particles were found in the nucleus. High-throughput sequencing of small RNAs from these citrus plants revealed a novel citrus strain of OFV, OFV-Cit2. Sequence comparisons with known orchid and citrus strains of OFV showed variation in the protein products encoded by genome segment 1 (RNA1). Strains of OFV clustered together based on host of origin, whether orchid or citrus, and were clearly separated from other dichorhaviruses described from infected citrus in Brazil. The variation in RNA1 between the original (now OFV-Cit1) and the new (OFV-Cit2) strain was not observed with genome segment 2 (RNA2), but instead, a common RNA2 molecule was shared among strains of OFV-Cit1 and -Cit2, a situation strikingly similar to OFV infecting orchids. We also collected mites at the affected groves, identified them as Brevipalpus californicus sensu stricto, and confirmed that they were infected by OFV-Cit1 or with both OFV-Cit1 and -Cit2. OFV-Cit1 and -Cit2 have coexisted at the same site in Toliman, Queretaro, Mexico since 2012. OFV strain-specific diagnostic tests were developed.

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Ever-increasing viral diversity associated with the red imported fire ant Solenopsis invicta (Formicidae: Hymenoptera)

Virology Journal ◽

10.1186/s12985-020-01469-w ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

César Augusto Diniz Xavier ◽

Margaret Louise Allen ◽

Anna Elizabeth Whitfield

Keyword(s):

Solenopsis Invicta ◽

De Novo ◽

Rna Virus ◽

Housekeeping Genes ◽

Virus Genome ◽

Single Strand ◽

Viral Diversity ◽

Red Imported Fire Ant ◽

Sequence Comparisons ◽

Data Set

Abstract Background Advances in sequencing and analysis tools have facilitated discovery of many new viruses from invertebrates, including ants. Solenopsis invicta is an invasive ant that has quickly spread worldwide causing significant ecological and economic impacts. Its virome has begun to be characterized pertaining to potential use of viruses as natural enemies. Although the S. invicta virome is the best characterized among ants, most studies have been performed in its native range, with less information from invaded areas. Methods Using a metatranscriptome approach, we further identified and molecularly characterized virus sequences associated with S. invicta, in two introduced areas, U.S and Taiwan. The data set used here was obtained from different stages (larvae, pupa, and adults) of S. invicta life cycle. Publicly available RNA sequences from GenBank’s Sequence Read Archive were downloaded and de novo assembled using CLC Genomics Workbench 20.0.1. Contigs were compared against the non-redundant protein sequences and those showing similarity to viral sequences were further analyzed. Results We characterized five putative new viruses associated with S. invicta transcriptomes. Sequence comparisons revealed extensive divergence across ORFs and genomic regions with most of them sharing less than 40% amino acid identity with those closest homologous sequences previously characterized. The first negative-sense single-stranded RNA virus genomic sequences included in the orders Bunyavirales and Mononegavirales are reported. In addition, two positive single-strand virus genome sequences and one single strand DNA virus genome sequence were also identified. While the presence of a putative tenuivirus associated with S. invicta was previously suggested to be a contamination, here we characterized and present strong evidence that Solenopsis invicta virus 14 (SINV-14) is a tenui-like virus that has a long-term association with the ant. Furthermore, based on virus sequence abundance compared to housekeeping genes, phylogenetic relationships, and completeness of viral coding sequences, our results suggest that four of five virus sequences reported, those being SINV-14, SINV-15, SINV-16 and SINV-17, may be associated to viruses actively replicating in the ant S. invicta. Conclusions The present study expands our knowledge about viral diversity associated with S. invicta in introduced areas with potential to be used as biological control agents, which will require further biological characterization.

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An Alignment-free Heuristic for Fast Sequence Comparisons with Applications to Phylogeny Reconstruction

Proceedings of the 2018 ACM International Conference on Bioinformatics, Computational Biology, and Health Informatics - BCB '18 ◽

10.1145/3233547.3233648 ◽

2018 ◽

Author(s):

Jodh Pannu ◽

Sriram P. Chockalingam ◽

Sharma V. Thankachan ◽

Srinivas Aluru

Keyword(s):

Phylogeny Reconstruction ◽

Sequence Comparisons ◽

Alignment Free

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Expanding the Diversity of the IS630-Tc1-mariner Superfamily: Discovery of a Unique DD37E Transposon and Reclassification of the DD37D and DD39D Transposons

Genetics ◽

10.1093/genetics/159.3.1103 ◽

2001 ◽

Vol 159 (3) ◽

pp. 1103-1115 ◽

Cited By ~ 1

Author(s):

Hongguang Shao ◽

Zhijian Tu

Keyword(s):

Phylogenetic Analyses ◽

Mosquito Species ◽

Open Reading Frames ◽

Inverted Repeats ◽

Sequence Comparisons ◽

Wide Range ◽

Multiple Copies ◽

Catalytic Motif ◽

Open The Doors ◽

Reading Frames

Abstract A novel transposon named ITmD37E was discovered in a wide range of mosquito species. Sequence analysis of multiple copies in three Aedes species showed similar terminal inverted repeats and common putative TA target site duplications. The ITmD37E transposases contain a conserved DD37E catalytic motif, which is unique among reported transposons of the IS630-Tc1-mariner superfamily. Sequence comparisons and phylogenetic analyses suggest that ITmD37E forms a novel family distinct from the widely distributed Tc1 (DD34E), mariner (DD34D), and pogo (DDxD) families in the IS630-Tc1-mariner superfamily. The inclusion in the phylogenetic analysis of recently reported transposons and transposons uncovered in our database survey provided revisions to previous classifications and identified two additional families, ITmD37D and ITmD39D, which contain DD37D and DD39D motifs, respectively. The above expansion and reorganization may open the doors to the discovery of related transposons in a broad range of organisms and help illustrate the evolution and structure-function relationships among these distinct transposases in the IS630-Tc1-mariner superfamily. The presence of intact open reading frames and highly similar copies in some of the newly characterized transposons suggests recent transposition. Studies of these novel families may add to the limited repertoire of transgenesis and mutagenesis tools for a wide range of organisms, including the medically important mosquitoes.

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Tempo and Mode of Ty Element Evolution in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/151.4.1341 ◽

1999 ◽

Vol 151 (4) ◽

pp. 1341-1351 ◽

Cited By ~ 2

Author(s):

I King Jordan ◽

John F McDonald

Keyword(s):

Saccharomyces Cerevisiae ◽

Negative Selection ◽

Sequence Variation ◽

Size Variation ◽

Sequence Comparisons ◽

Ty Elements ◽

Ty Element ◽

Amino Acid Sequence Variation ◽

Element Evolution ◽

High Level

Abstract The Saccharomyces cerevisiae genome contains five families of long terminal repeat (LTR) retrotransposons, Ty1–Ty5. The sequencing of the S. cerevisiae genome provides an unprecedented opportunity to examine the patterns of molecular variation existing among the entire genomic complement of Ty retrotransposons. We report the results of an analysis of the nucleotide and amino acid sequence variation within and between the five Ty element families of the S. cerevisiae genome. Our results indicate that individual Ty element families tend to be highly homogenous in both sequence and size variation. Comparisons of within-element 5′ and 3′ LTR sequences indicate that the vast majority of Ty elements have recently transposed. Furthermore, intrafamily Ty sequence comparisons reveal the action of negative selection on Ty element coding sequences. These results taken together suggest that there is a high level of genomic turnover of S. cerevisiae Ty elements, which is presumably in response to selective pressure to escape host-mediated repression and elimination mechanisms.

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The Candidate Genes Underlying a Stably Expressed QTL for Low Temperature Germinability in Rice (Oryza sativa L.)

Rice ◽

10.1186/s12284-020-00434-z ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Tifeng Yang ◽

Lian Zhou ◽

Junliang Zhao ◽

Jingfang Dong ◽

Qing Liu ◽

...

Keyword(s):

Low Temperature ◽

Differential Expression ◽

Candidate Genes ◽

Complex Traits ◽

Molecular Breeding ◽

Genome Wide Association Study ◽

Oryza Sativa L ◽

Sequence Comparisons ◽

Cold Environments ◽

Promising Source

Abstract Background Direct seeding is an efficient cultivation technique in rice. However, poor low temperature germinability (LTG) of modern rice cultivars limits its application. Identifying the genes associated with LTG and performing molecular breeding is the fundamental way to address this issue. However, few LTG QTLs have been fine mapped and cloned so far. Results In the present study, the LTG evaluation of 375 rice accessions selected from the Rice Diversity Panel 2 showed that there were large LTG variations within the population, and the LTG of Indica group was significantly higher than that of Japonica and Aus groups (p < 0.01). In total, eleven QTLs for LTG were identified through genome-wide association study (GWAS). Among them, qLTG_sRDP2–3/qLTG_JAP-3, qLTG_AUS-3 and qLTG_sRDP2–12 are first reported in the present study. The QTL on chromosome 10, qLTG_sRDP2–10a had the largest contribution to LTG variations in 375 rice accessions, and was further validated using single segment substitution line (SSSL). The presence of qLTG_sRDP2–10a could result in 59.8% increase in LTG under 15 °C low temperature. The expression analysis of the genes within qLTG_sRDP2–10a region indicated that LOC_Os10g22520 and LOC_Os10g22484 exhibited differential expression between the high and low LTG lines. Further sequence comparisons revealed that there were insertion and deletion sequence differences in the promoter and intron region of LOC_Os10g22520, and an about 6 kb variation at the 3′ end of LOC_Os10g22484 between the high and low LTG lines, suggesting that the sequence variations of the two genes could be the cause for their differential expression in high and low LTG lines. Conclusion Among the 11 QTLs identified in this study, qLTG_sRDP2–10a could also be detected in other three studies using different germplasm under different cold environments. Its large effect and stable expression make qLTG_sRDP2–10a particularly valuable in rice breeding. The two genes, LOC_Os10g22484 and LOC_Os10g22520, were considered as the candidate genes underlying qLTG_sRDP2–10a. Our results suggest that integrating GWAS and SSSL can facilitate identification of QTL for complex traits in rice. The identification of qLTG_sRDP2–10a and its candidate genes provide a promising source for gene cloning of LTG and molecular breeding for LTG in rice.

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Sequence and phylogentic analysis of MERS-CoV in Saudi Arabia, 2012–2019

Virology Journal ◽

10.1186/s12985-021-01563-7 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Mohamed A. Farrag ◽

Haitham M. Amer ◽

Rauf Bhat ◽

Fahad N. Almajhdi

Keyword(s):

Middle East ◽

Gene Sequence ◽

Selective Pressure ◽

Mutation Rates ◽

Receptor Binding Domain ◽

Sequence Comparisons ◽

S Gene ◽

Clade B ◽

Human Coronaviruses ◽

Early Phases

Abstract Background The Middle East Respiratory Syndrome-related Coronavirus (MERS-CoV) continues to exist in the Middle East sporadically. Thorough investigations of the evolution of human coronaviruses (HCoVs) are urgently required. In the current study, we studied amplified fragments of ORF1a/b, Spike (S) gene, ORF3/4a, and ORF4b of four human MERS-CoV strains for tracking the evolution of MERS-CoV over time. Methods RNA isolated from nasopharyngeal aspirate, sputum, and tracheal swabs/aspirates from hospitalized patients with suspected MERS-CoV infection were analyzed for amplification of nine variable genomic fragments. Sequence comparisons were done using different bioinformatics tools available. Results Several mutations were identified in ORF1a/b, ORF3/4a and ORF4b, with the highest mutation rates in the S gene. Five codons; 4 in ORF1a and 1 in the S gene, were found to be under selective pressure. Characteristic amino acid changes, potentially hosted and year specific were defined across the S protein and in the receptor-binding domain Phylogenetic analysis using S gene sequence revealed clustering of MERS-CoV strains into three main clades, A, B and C with subdivision of with clade B into B1 to B4. Conclusions In conclusion, MERS-CoV appears to continuously evolve. It is recommended that the molecular and pathobiological characteristics of future MERS-CoV strains should be analyzed on regular basis to prevent potential future outbreaks at early phases.

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