DNA Sequence Datasets Research Articles

Multigene phylogeny and taxonomy of Dendryphion hydeiand Torula hydeispp. nov. from herbaceous litter in northern Thailand.

During our studies on asexual fungi colonizing herbaceous litter in northern Thailand, we discovered two new fungal species, viz. Dendryphion hydei and Torula hydei spp. nov. The latter are examined, and their morphological characters are described as well as their DNA sequences from ribosomal and protein coding genes are analysed to infer their phylogenetic relationships with extant fungi. Torula hydei is different from other similar Torula species in having tiny and catenate conidia. Dendryphion hydei can be distinguished from other similar Dendryphion species in having large conidiophores and subhyaline to pale olivaceous brown, 2-4(-5)-septate conidia. Multigene phylogenetic analyses of a combined LSU, SSU, TEF1-α, RPB2 and ITS DNA sequence dataset generated from maximum likelihood and Bayesian inference analyses indicate that T. hydei forms a distinct lineage and basal to T. fici. Dendryphion hydei forms a distinct lineage and basal to D. europaeum, D. comosum, D. aquaticum and D. fluminicola within Torulaceae (Pleosporales, Dothideomycetes).

Subsistence strategy was the main factor driving population differentiation in the bidirectional corridor of the African Sahel.

The Sahel belt is occupied by populations who use two types of subsistence strategy, nomadic pastoralism and sedentary farming, and who belong to three linguistic families, Niger-Congo, Nilo-Saharan, and Afro-Asiatic. Little is known, however, about the origins of these two populations and their mutual genetic relationships. We have built a large dataset of mitochondrial DNA sequences and Y chromosomal STR haplotypes of pastoralists and farmers belonging to all three linguistic phyla in the western, central, and eastern parts of the Sahel. We calculated pairwise genetic, geographic, and linguistic distances between populations and analyzed the effects of geography, language, and subsistence on population genetic structure. We found that subsistence mode significantly contributed to the generally low population structure in the Sahel and that language affiliation plays a more important role for pastoralists than for farmers. We also demonstrated that geographic isolation significantly influenced the population structure of sedentary farmers but not of nomadic pastoralists. Finally, we found haplotypes shared between the Fulani and Arabic-speaking Baggara, supporting the theory of Baggarization, which explains the recent adaptation of Arabic-speaking nomads in the Sahel region through contact with autochthonous sub-Saharan populations. Based on various genetic and archaeological evidence pertaining to the Sahel, we suggest that the idea of a bidirectional Sahelian corridor is valid, but that pastoralists made a more important contribution to its population structure. It is also possible that agropastoralists diverged into farmers and pastoralists in the early stages of formation of the Sahelian gene pool.

Ipyrad: Interactive assembly and analysis of RADseq datasets.

ipyrad is a free and open source tool for assembling and analyzing restriction site-associated DNA sequence datasets using de novo and/or reference-based approaches. It is designed to be massively scalable to hundreds of taxa and thousands of samples, and can be efficiently parallelized on high performance computing clusters. It is available both as a command line interface and as a Python package with an application programming interface, the latter of which can be used interactively to write complex, reproducible scripts and implement a suite of downstream analysis tools. ipyrad is a free and open source program written in Python. Source code is available from the GitHub repository (https://github.com/dereneaton/ipyrad/), and Linux and MacOS installs are distributed through the conda package manager. Complete documentation, including numerous tutorials, and Jupyter notebooks demonstrating example assemblies and applications of downstream analysis tools are available online: https://ipyrad.readthedocs.io/.

High genetic connectivity in a gastropod with long-lived planktonic larvae

AbstractGenetic connectivity plays a crucial role in shaping the geographic structure of species. Our aim in this study was to explore the pattern of genetic connectivity in Bursa scrobilator, an iconic marine caenogastropod with long-lived pelagic larvae. Our study was based on the analysis of DNA sequence data for the 658-bp barcoding fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. This is the largest DNA sequence dataset assembled to date for B. scrobilator. These data confirm that the two recently described subspecies B. scrobilator scrobilator (Linnaeus, 1758), from the Mediterranean and Macaronesia, and B. s. coriacea (Reeve, 1844), from West Africa, constitute two evolutionarily significant units (ESUs). We found that for the nominal subspecies, the variation in morphology (shell, radula and gross anatomy) and DNA sequences was not geographically structured, and this agrees with what we would expect in a species with high connectivity at the larval stage. The divergence between the two subspecies cannot be easily explained by isolation by distance, and we would argue that one or more extrinsic factors may have played a role in isolating the two ESUs and maintaining that isolation.

Unraveling the diversification and systematic puzzle of the highly polymorphicPsammobates tentorius(Bell, 1828) complex (Reptilia: Testudinidae) through phylogenetic analyses and species delimitation approaches

The high level of phenotypic diversity in southern African tent tortoises (Psammobates tentorius complex) has for decades prevented systematists from developing a stable taxonomy for the group. Here, we used a comprehensive DNA sequence dataset (mtDNA: Cytb, ND4, ND4 adjacent tRNA-His, and tRNA-Ser, 12S, 16S; and nDNA: PRLR gene) of 455 specimens, and the latest phylogenetic and species delimitation analytical procedures, to unravel the long-standing P. tentorius complex systematic puzzle. Our results for mtDNA and nDNA were incongruent, with the poorly supported nDNA phylogeny differentiating the three recognized subspecies, and showing potential hybridization in some regions. In contrast, the concatenated mtDNA phylogeny identified seven operational taxonomic units, with strong support. Clades 1, 4, 5, and 7 corresponded to tortoises identified as P. t. tentorius, clade 3 to P. t. trimeni, and clades 2 and 6 to P. t. verroxii. Our analyses showed conflicting topologies for the placement of C6 (P. t. verroxii north of the Orange River), with stronger support for it being sister to C2 + C3 than to the other clades. Clades 1, 2, and 6 had significantly higher genetic diversity than clades 3, 4, 5, and 7, perhaps because these clades inhabit substantially larger areas. The potential for future cladogenic radiations seems high in C1 and C6, particularly in C6 for which the within-clade diversification level was highest. Further research involving microsatellite DNA, phylogeographic evaluations, and morphological variation among clades is crucial for understanding the adaptive radiation of the P. tentorius complex and for modifying their taxonomy.

A55 Molecular systematics of sturgeon nucleocytoplasmic large DNA viruses

Namao virus (NV) is a sturgeon nucleocytoplasmic large DNA virus (sNCLDV) that can cause a lethal disease of the integumentary system in lake sturgeon Acipenser fulvescens. As a group, the sNCLDV have not been assigned to any currently recognized taxonomic family of viruses. In this study, a dataset of NV DNA sequences was generated and assembled as two non-overlapping contigs of 306 and 448 base pairs (bp) and then used to conduct a comprehensive systematics analysis using Bayesian phylogenetic inference for NV, other sNCLDV, and representative members of six families of the NCLDV superfamily. The phylogeny of NV was reconstructed using protein homologues encoded by nine nucleocytoplasmic virus orthologous genes (NCVOGs): NCVOG0022—mcp, NCVOG0038—DNA polymerase B elongation subunit, NCVOG0076—VV A18-type helicase, NCVOG0249—VV A32-type ATPase, NCVOG0262—AL2 VLTF3-like transcription factor, NCVOG0271—RNA polymerase II subunit II, NCVOG0274—RNA polymerase II subunit I, NCVOG0276—ribonucleotide reductase small subunit, and NCVOG1117—mRNA capping enzyme. The accuracy of our phylogenetic method was evaluated using a combination of Bayesian statistical analysis and congruence analysis. Stable tree topologies were obtained with datasets differing in target molecule(s), sequence length, and taxa. Congruent topologies were obtained in phylogenies constructed using individual protein datasets and when four proteins were used in a concatenated approach. The major capsid protein phylogeny indicated that ten representative sNCLDV form a monophyletic group comprised of four lineages within a polyphyletic Mimi-Phycodnaviridae group of taxa. Overall, the analyses revealed that Namao virus is a member of the Mimiviridae family with strong and consistent support for a clade containing NV and CroV as sister taxa.

Abstract 4689: Subclone-specific evolution of tumor phenotypes – A framework to study subclone-specific gene expression from a combination of bulk DNA and single cell RNA sequencing data

Abstract Several approaches are now available for subclonal reconstruction of heterogeneous tumor biopsies from somatic variant allele frequencies measured in bulk DNA sequencing datasets, including our own SubcloneSeeker program. However, to understand how chemoresistance, relapse, or metastasis evolves at a subclonal level, we also need to study the molecular phenotype corresponding to each subclone. Single-cell RNAseq technologies now allow one to study the transcriptomic characteristics and phenotypic behaviors of individual cells, but new algorithms are needed to link these cells to the genomically defined tumor subclones they represent. Here we present a computational approach to make such cell assignments, using a combination of bulk DNA sequencing data (WGS or WES), and single cell RNA sequencing (scRNAseq) collected from the same tissues. Subclones constructed from bulk DNA sequencing data are defined by specific combinations of somatic mutations (SNVs and CNVs). Our algorithm uses the scRNA-seq reads to assess which of these subclone-defining mutations are present in each individual cell, then utilizes a Bayesian probabilistic framework for making the cell-to-subclone assignment. This framework overcomes the challenges of sparse scRNA-seq read coverage, and maximizes the accuracy and efficiency of cell assignment. We have successfully applied this method to multiple longitudinal and metastatic cancer patient datasets, representing both WES and WGS bulk DNA sequencing, as well as datasets collected using the 10X Chromium and Fluidigm C1 technologies. Our algorithm uses both somatically acquired CNV and SNV events in the tumor for cell assignment. Using our approach, as many of 80% of tumor cells could be assigned to specific subclones, enabling comparative gene expression and pathway analysis across subclones. Citation Format: Yi Qiao, Xiaomeng Huang, Samuel Brady, Andrea Bild, David Bowtell, William Johnson, Gabor Marth. Subclone-specific evolution of tumor phenotypes – A framework to study subclone-specific gene expression from a combination of bulk DNA and single cell RNA sequencing data [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4689.

DNA sequence-based identification and barcoding of a morphologically highly plastic lichen forming fungal genus (Parmotrema, Parmeliaceae) from the tropics

Tropical regions harbor rich biodiversity but are relatively poorly explored, especially in lesser known taxonomic groups, such as lichenized fungi. In addition, the identification of species is complicated by frequent occurrence of cryptic species and the plasticity of phenotypic features traditionally used to identify species. Here, we aim to explore species diversity and provide tools for accurate sample identification of the genus Parmotrema from rainforests in Thailand. We gathered a three-locus DNA sequence data set and this was analysed in phylogenetic and DNA barcode frameworks. While some morpho-species were recovered as monophyletic, others did not form monophyletic groups. Our study unmasked cryptic lineages in Parmotrema species distributed in the tropics and show that phenotype-based sample identification may underestimate species diversity in this group of lichens. Further, genetic distances based on ITS DNA sequences (i.e. DNA barcode approach) were shown to be a valuable tool for sample identification. In addition, our study highlights the need for taxonomic reexamination of the following phenotypically delimited species: P. corniculans, P. crinitum, P. haitiense, P. maclayanum, P. perlatum and P. subtinctorium.

Minor allele frequency thresholds strongly affect population structure inference with genomic data sets.

A common method of minimizing errors in large DNA sequence data sets is to drop variable sites with a minor allele frequency (MAF) below some specified threshold. Although widespread, this procedure has the potential to alter downstream population genetic inferences and has received relatively little rigorous analysis. Here we use simulations and an empirical single nucleotide polymorphism data set to demonstrate the impacts of MAF thresholds on inference of population structure-often the first step in analysis of population genomic data. We find that model-based inference of population structure is confounded when singletons are included in the alignment, and that both model-based and multivariate analyses infer less distinct clusters when more stringent MAF cutoffs are applied. We propose that this behaviour is caused by the combination of a drop in the total size of the data matrix and by correlations between allele frequencies and mutational age. We recommend a set of best practices for applying MAF filters in studies seeking to describe population structure with genomic data.

Archaeorhizomycetes Spatial Distribution in Soils Along Wide Elevational and Environmental Gradients Reveal Co-abundance Patterns With Other Fungal Saprobes and Potential Weathering Capacities.

Archaeorhizomycetes, a widespread fungal class with a dominant presence in many soil environments, contains cryptic filamentous species forming plant-root associations whose role in terrestrial ecosystems remains unclear. Here, we apply a correlative approach to identify the abiotic and biotic environmental variables shaping the distribution of this fungal group. We used a DNA sequencing dataset containing Archaeorhizomycetes sequences and environmental variables from 103 sites, obtained through a random-stratified sampling in the Western Swiss Alps along a wide elevation gradient (>2,500 m). We observed that the relative abundance of Archaeorhizomycetes follows a “humped-shaped” curve. Fitted linear and quadratic generalized linear models revealed that both climatic (minimum temperature, precipitation sum, growing degree-days) and edaphic (carbon, hydrogen, organic carbon, aluminum oxide, and phyllosilicates) factors contribute to explaining the variation in Archaeorhizomycetes abundance. Furthermore, a network inference topology described significant co-abundance patterns between Archaeorhizomycetes and other saprotrophic and ectomycorrhizal fungal taxa. Overall, our results provide strong support to the hypothesis that Archaeorhizomycetes in this area have clear ecological requirements along wide, elevation-driven abiotic and biotic gradients. Additionally, correlations to soil redox parameters, particularly with phyllosilicates minerals, suggest Archaeorhizomycetes might be implied in biological rock weathering. Such soil taxa-environment studies along wide gradients are thus a useful complement to latitudinal field observations and culture-based approaches to uncover the ecological roles of cryptic soil organisms.

Neostagonosporellasichuanensis gen. et sp. nov. (Phaeosphaeriaceae, Pleosporales) on Phyllostachysheteroclada (Poaceae) from Sichuan Province, China.

Neostagonosporellasichuanensis sp. nov. was found on Phyllostachysheteroclada collected from Sichuan Province in China and is introduced in a new genus Neostagonosporella gen. nov. in this paper. Evidence for the placement of the new taxon in the family Phaeosphaeriaceae is supported by morphology and phylogenetic analysis of a combined LSU, SSU, ITS and TEF 1-α DNA sequence dataset. Maximum-likelihood, maximum-parsimony and Bayesian inference phylogenetic analyses support Neostagonosporella as a distinct genus within this family. The new genus is compared with related genera of Phaeosphaeriaceae and full descriptions and illustrations are provided. Neostagonosporella is characterised by its unique suite of characters, such as multiloculate ascostromata and cylindrical to fusiform, transversely multiseptate, straight or curved ascospores, which are widest at the central cells. Conidiostromata are multiloculate, fusiform to long fusiform or rhomboid, with two types conidia; macroconidia vermiform or subcylindrical to cylindrical, transversely multiseptate, sometimes curved, almost equidistant between septa and microconidia oval, ellipsoidal or long ellipsoidal, aseptate, rounded at both ends. An updated phylogeny of the Phaeosphaeriaceae based on multigene analysis is provided.

Identifying Extrinsic versus Intrinsic Drivers of Variation in Cell Behavior in Human iPSC Lines from Healthy Donors

SummaryLarge cohorts of human induced pluripotent stem cells (iPSCs) from healthy donors are a potentially powerful tool for investigating the relationship between genetic variants and cellular behavior. Here, we integrate high content imaging of cell shape, proliferation, and other phenotypes with gene expression and DNA sequence datasets from over 100 human iPSC lines. By applying a dimensionality reduction approach, Probabilistic Estimation of Expression Residuals (PEER), we extracted factors that captured the effects of intrinsic (genetic concordance between different cell lines from the same donor) and extrinsic (cell responses to different fibronectin concentrations) conditions. We identify genes that correlate in expression with intrinsic and extrinsic PEER factors and associate outlier cell behavior with genes containing rare deleterious non-synonymous SNVs. Our study, thus, establishes a strategy for examining the genetic basis of inter-individual variability in cell behavior.

Moving Just Enough Deep Sequencing Data to Get the Job Done.

Motivation:As the size of high-throughput DNA sequence datasets continues to grow, the cost of transferring and storing the datasets may prevent their processing in all but the largest data centers or commercial cloud providers. To lower this cost, it should be possible to process only a subset of the original data while still preserving the biological information of interest.Results:Using 4 high-throughput DNA sequence datasets of differing sequencing depth from 2 species as use cases, we demonstrate the effect of processing partial datasets on the number of detected RNA transcripts using an RNA-Seq workflow. We used transcript detection to decide on a cutoff point. We then physically transferred the minimal partial dataset and compared with the transfer of the full dataset, which showed a reduction of approximately 25% in the total transfer time. These results suggest that as sequencing datasets get larger, one way to speed up analysis is to simply transfer the minimal amount of data that still sufficiently detects biological signal.Availability:All results were generated using public datasets from NCBI and publicly available open source software.

Phylogeny and biogeography of the narrowly endemic Doronicum cataractarum (Asteraceae) from the eastern European Alps: Pleistocene origin from Alpine ancestors rather than Tertiary relic with southwest Asian affinity

Distribution areas of narrowly endemic species in the European Alps often coincide with Pleistocene refugia, suggesting that allopatric divergence due to Pleistocene range shifts might have been instrumental in their origin. Here, we infer the phylogenetic position of the locally endemic Doronicum cataractarum testing previous hypotheses with respect to its biogeographic and temporal origin (Tertiary origin with southwest Asian affinities versus possibly Pleistocene origin in the Alps). To this end, we extended existing genus-wide data sets of nuclear and plastid DNA sequences and obtained sequences from two hitherto not used low copy nuclear markers. These data sets were analyzed, as single markers and jointly in a concatenated matrix, using maximum parsimony and maximum likelihood. Temporal and spatial origins of D. cataractarum were inferred using mean path lengths and dispersal–vicariance analysis, respectively. Phylogenetic resolution was limited, but several geographically coherent groups were identified, including the Grandiflora group comprising southern and central European mountain species. Congruently, D. cataractarum was inferred as most closely related to Alpine species from the Grandiflora group (D. clusii, D. stiriacum and D. glaciale), but neither to southwest Asian species nor to European D. austriacum. The origin of D. cataractarum was conservatively dated to about 1.9 Mya and inferred to have taken place in the Alps. The striking morphological differences between D. cataractarum and the most closely related species likely are the result of adaptation to different habitats or, alternatively, the presence of plesiomorphic traits in D. cataractarum.

Cluster oligonucleotide signatures for rapid identification by sequencing

BackgroundOligonucleotide signatures (signatures) have been widely used for studying microbial diversity and function in wet-lab settings, but using them for accurate in silico identification of organisms from high-throughput sequencing (HTS) data is only a proof of concept. Existing signature design programs for sequence signatures (signatures matching exactly one sequence) or clade signatures (signatures matching every sequence in a phylogenetic clade) are not able to identify all possible polymorphic sites for sequences with high similarity and perform poorly when handling large genome sequencing datasets.ResultsWe introduce cluster signatures: subsequences that match perfectly and exclusively any group of sequences in a data set. Cluster signatures provide complete recall for primer/probe design and increased discrimination between sequences beyond that of clade signatures. Using cluster signatures for in silico identification of HTS targets achieves good precision/recall and running time performance. This method has been implemented into an open source tool, the Automated Oligonucleotide Design Pipeline (adop), included in supplementary material and available at: https://bitbucket.org/wenchen_aafc/aodp_v2.0_release.ConclusionsCluster signatures provide a rapid and universal analysis tool to identify all possible short diagnostic DNA markers and variants from any DNA sequencing dataset. They are particularly useful in discriminating genetic material from closely related organisms and in detecting deleterious mutations in highly or perfectly conserved genomic sites.

Protective role of the vulture facial skin and gut microbiomes aid adaptation to scavenging

BackgroundVultures have adapted the remarkable ability to feed on carcasses that may contain microorganisms that would be pathogenic to most other animals. The holobiont concept suggests that the genetic basis of such adaptation may not only lie within their genomes, but additionally in their associated microbes. To explore this, we generated shotgun DNA sequencing datasets of the facial skin and large intestine microbiomes of the black vulture (Coragyps atratus) and the turkey vulture (Cathartes aura). We characterized the functional potential and taxonomic diversity of their microbiomes, the potential pathogenic challenges confronted by vultures, and the microbial taxa and genes that could play a protective role on the facial skin and in the gut.ResultsWe found microbial taxa and genes involved in diseases, such as dermatitis and pneumonia (more abundant on the facial skin), and gas gangrene and food poisoning (more abundant in the gut). Interestingly, we found taxa and functions with potential for playing beneficial roles, such as antilisterial bacteria in the gut, and genes for the production of antiparasitics and insecticides on the facial skin. Based on the identified phages, we suggest that phages aid in the control and possibly elimination, as in phage therapy, of microbes reported as pathogenic to a variety of species. Interestingly, we identified Adineta vaga in the gut, an invertebrate that feeds on dead bacteria and protozoans, suggesting a defensive predatory mechanism. Finally, we suggest a colonization resistance role through biofilm formation played by Fusobacteria and Clostridia in the gut.ConclusionsOur results highlight the importance of complementing genomic analyses with metagenomics in order to obtain a clearer understanding of the host-microbial alliance and show the importance of microbiome-mediated health protection for adaptation to extreme diets, such as scavenging.

Genotyping-by-sequencing (GBS), ITS and cpDNA phylogenies reveal the existence of a distinct Pyrenean/Cantabrian lineage in the European high mountain genus Homogyne (Asteraceae) and imply dual westward migration of the genus

Quaternary climatic oscillations have been a major factor in shaping plant diversity and distribution in the European Alpine System (EAS). Plants responded to these oscillations with repeated changes in their abundance and geographical distribution. However, oscillating shifts in geographical distribution have only rarely been reported in molecular analyses of genetic variation across the EAS. Homogyne, a genus endemic to the EAS, contains three species. While H. discolor and H. sylvestris are confined to the periphery of the Eastern Alps, H. alpina is widespread across the EAS. In phylogenetic reconstructions of a broad sample of Homogyne using DNA sequence data sets of the nuclear ribosomal internal transcribed spacer (ITS), plastid DNA (ndhF-rpl32, rpl32-trnL, psbA-trnH) and genotyping-by-sequencing (GBS), accessions of H. alpina from the Pyrenees and the Cantabrian Mts. form a clade which groups in conflicting positions. While the exact relationship of this Pyrenean/Cantabrian clade of H. alpina remains unclear, our data clearly imply that this clade is a lineage distinct from the remaining accessions of H. alpina (H. alpina s.str.). An ancestral area analysis unambiguously revealed the Eastern Alps as the ancestral area of the genus. Considering that relationships within H. alpina s.str. clearly illustrate East to West expansion, the identification of a Pyrenean/Cantabrian clade implies that westward expansion from an ancestral area in the Eastern Alps took place twice in the genus. Although the extant distributions of the Pyrenean/Cantabrian clade and H. alpina s.str. are mutually exclusive, plastid DNA evidence may imply past contact and hybridization between the two clades.

Morphological and phylogenetic characterisation of novel Cytospora species associated with mangroves.

Mangroves are relatively unexplored habitats and have been shown to harbour a number of novel species of fungi. In this study, samples of microfungi were collected from symptomatic branches, stem and leaves of the mangrove species Xylocarpusgranatum, X.moluccensis and Lumnitzeraracemosa and examined morphologically. The phylogeny recovered supports our morphological data to introduce three new species, Cytosporalumnitzericola, C.thailandica and C.xylocarpi. In addition, a combined multi-gene DNA sequence dataset (ITS, LSU, ACT and RPB2) was analysed to investigate phylogenetic relationships of isolates and help in a more reliable species identification.

Molecular systematics of sturgeon nucleocytoplasmic large DNA viruses

Namao virus (NV) is a sturgeon nucleocytoplasmic large DNA virus (sNCLDV) that can cause a lethal disease of the integumentary system in lake sturgeon Acipenser fulvescens. As a group, the sNCLDV have not been assigned to any currently recognized taxonomic family of viruses. In this study, a data set of NV DNA sequences was generated and assembled as two non-overlapping contigs of 306,448 bp and then used to conduct a comprehensive systematics analysis using Bayesian inference of phylogeny for NV, other sNCLDV and representative members of six families of the NCLDV superfamily. The phylogeny of NV was reconstructed using protein homologues encoded by nine nucleocytoplasmic virus orthologous genes (NCVOGs): NCVOG0022 – mcp, NCVOG0038 – DNA polymerase B elongation subunit, NCVOG0076 – VV A18-type helicase, NCVOG0249 – VV A32-type ATPase, NCVOG0262 – AL2 VLTF3-like transcription factor, NCVOG0271 – RNA polymerase II subunit II, NCVOG0274 – RNA polymerase II subunit I, NCVOG0276 – ribonucleotide reductase small subunit and NCVOG1117 – mRNA capping enzyme. The accuracy of our phylogenetic method was evaluated using a combination of Bayesian statistical analysis and congruence analysis. Stable tree topologies were obtained with data sets differing in target molecule(s), sequence length and taxa. Congruent topologies were obtained in phylogenies constructed using individual protein data sets. The major capsid protein phylogeny inferred that ten representative sNCLDV form a monophyletic group comprised of four lineages within a polyphyletic Mimi-Phycodnaviridae group of taxa. Overall, the analyses revealed that Namao virus is a member of the Mimiviridae family with strong and consistent support for a clade containing NV and CroV as sister taxa.

Mining DNA Sequence Patterns with Constraints Using Hybridization of Firefly and Group Search Optimization

Abstract DNA sequence mining is essential in the study of the structure and function of the DNA sequence. A few exploration works have been published in the literature concerning sequence mining in information mining task. Similarly, in our past paper, an effective sequence mining was performed on a DNA database utilizing constraint measures and group search optimization (GSO). In that study, GSO calculation was utilized to optimize the sequence extraction process from a given DNA database. However, it is apparent that, occasionally, such an arbitrary seeking system does not accompany the optimal solution in the given time. To overcome the problem, we proposed in this work multiple constraints with hybrid firefly and GSO (HFGSO) algorithm. The complete DNA sequence mining process comprised the following three modules: (i) applying prefix span algorithm; (ii) calculating the length, width, and regular expression (RE) constraints; and (iii) optimal mining via HFGSO. First, we apply the concept of prefix span, which detects the frequent DNA sequence pattern using a prefix tree. Based on this prefix tree, length, width, and RE constraints are applied to handle restrictions. Finally, we adopt the HFGSO algorithm for the completeness of the mining result. The experimentation is carried out on the standard DNA sequence dataset, and the evaluation with DNA sequence dataset and the results show that our approach is better than the existing approach.