scholarly journals EPA-ng: Massively Parallel Evolutionary Placement of Genetic Sequences

2018 ◽  
Author(s):  
Pierre Barbera ◽  
Alexey M. Kozlov ◽  
Lucas Czech ◽  
Benoit Morel ◽  
Diego Darriba ◽  
...  

AbstractNext Generation Sequencing (NGS) technologies have led to a ubiquity of molecular sequence data. This data avalanche is particularly challenging in metagenetics, which focuses on taxonomic identification of sequences obtained from diverse microbial environments. To achieve this, phylogenetic placement methods determine how these sequences fit into an evolutionary context. Previous implementations of phylogenetic placement algorithms, such as the Evolutionary Placement Algorithm (EPA) included in RAxML, or pplacer, are being increasingly used for this purpose. However, due to the steady progress in NGS technologies, the current implementations face substantial scalability limitations. Here we present EPA-ng, a complete reimplementation of the EPA that is substantially faster, offers a distributed memory parallelization, and integrates concepts from both, RAxML-EPA, and pplacer. EPA-ng can be executed on standard shared memory, as well as on distributed memory systems (e.g., computing clusters). To demonstrate the scalability of EPA-ng we placed 1 billion metagenetic reads from the Tara Oceans Project onto a reference tree with 3,748 taxa in just under 7 hours, using 2,048 cores. Our performance assessment shows that EPA-ng outperforms RAxML-EPA and pplacer by up to a factor of 30 in sequential execution mode, while attaining comparable parallel efficiency on shared memory systems. We further show that the distributed memory parallelization of EPA-ng scales well up to 3,520 cores. EPA-ng is available under the AGPLv3 license: https://github.com/Pbdas/epa-ng

Phytotaxa ◽  
2019 ◽  
Vol 394 (4) ◽  
pp. 267
Author(s):  
YASAMAN SALMAKI ◽  
JOCHEN MÜLLER

After more than 100 years since the first discovery, Scutellaria xylorrhiza, a critically endangered species listed in the Red List of Iranian plants had been presumed to be extinct. We rediscovered recently a population of this species in Sofeh Mountain South of Isfahan. Here, we perform the taxonomic history, phylogenetic placement and conservation status of this endemic species, and compare our findings with the description provided in the protologue and other references. Besides the updated description, notes on typification and new photographs of this species are presented. In addition, we compare S. xylorrhiza with other related Scutellaria species occurring in Iran and neighboring regions using molecular sequence data from the nuclear ribosomal DNA (Internal Transcribed Spacer). Our morphological and sequence analyses show that S. xylorrhiza is close to S. ariana.


Phytotaxa ◽  
2014 ◽  
Vol 176 (1) ◽  
pp. 219 ◽  
Author(s):  
ASHA J. DISSANAYAKE ◽  
RUVISHIKA S. JAYAWARDENA ◽  
SARANYAPHAT BOONMEE ◽  
KASUN M. THAMBUGALA ◽  
QING TIAN ◽  
...  

The family Myriangiaceae is relatively poorly known amongst the Dothideomycetes and includes genera which are saprobic, epiphytic and parasitic on the bark, leaves and branches of various plants. The family has not undergone any recent revision, however, molecular data has shown it to be a well-resolved family closely linked to Elsinoaceae in Myriangiales. Both morphological and molecular characters indicate that Elsinoaceae differs from Myriangiaceae. In Elsinoaceae, small numbers of asci form in locules in light coloured pseudostromata, which form typical scab-like blemishes on leaf or fruit surfaces. The coelomycetous, “Sphaceloma”-like asexual state of Elsinoaceae, form more frequently than the sexual state; conidiogenesis is phialidic and conidia are 1-celled and hyaline. In Myriangiaceae, locules with single asci are scattered in a superficial, coriaceous to sub-carbonaceous, black ascostromata and do not form scab-like blemishes. No asexual state is known. In this study, we revisit the family Myriangiaceae, and accept ten genera, providing descriptions and discussion on the generic types of Anhellia, Ascostratum, Butleria, Dictyocyclus, Diplotheca, Eurytheca, Hemimyriangium, Micularia, Myriangium and Zukaliopsis. The genera of Myriangiaceae are compared and contrasted. Myriangium duriaei is the type species of the family, while Diplotheca is similar and may possibly be congeneric. The placement of Anhellia in Myriangiaceae is supported by morphological and molecular data. Because of similarities with Myriangium, Ascostratum (A. insigne), Butleria (B. inaghatahani), Dictyocyclus (D. hydrangea), Eurytheca (E. trinitensis), Hemimyriangium (H. betulae), Micularia (M. merremiae) and Zukaliopsis (Z. amazonica) are placed in Myriangiaceae. Molecular sequence data from fresh collections is required to confirm the relationships and placement of the genera in this family.


Zootaxa ◽  
2017 ◽  
Vol 4238 (1) ◽  
pp. 58 ◽  
Author(s):  
ATSUSHI MOCHIZUKI ◽  
CHARLES S. HENRY ◽  
PETER DUELLI

The small lacewing genus Apertochrysa comprises species from Africa, Asia and Australia. All lack a tignum, but otherwise resemble distantly related genera. We show that Apertochrysa does not form a monophyletic clade, based on analyses of molecular sequence data and morphological traits such as the presence and shape of the male gonapsis, wing venation, and larval setae. Apertochrysa kichijoi forms a clade with Eremochrysa, Suarius and Chrysemosa, whereas A. albolineatoides belongs to a clade that includes Cunctochrysa. Apertochrysa albolineatoides should become a new combination as Cunctochrysa albolineatoides, while A. kichijoi will have to be transferred to a new genus. The Australian A. edwardsi, the African A. eurydera and the type species of the genus Apertochrysa, A. umbrosa, join the large Pseudomallada group. Relationships of A. umbrosa are less certain, because for it we could amplify only one of the three nuclear genes used in the overall analysis. However, in all morphological traits tested, that species strongly resembles A. edwardsi and A. eurydera and thus is very likely just another exceptional Pseudomallada lacking a tignum. The fate of the genus name Apertochrysa depends on additional molecular and morphological analyses of A. umbrosa. 


2009 ◽  
Vol 364 (1527) ◽  
pp. 2197-2207 ◽  
Author(s):  
Peter G. Foster ◽  
Cymon J. Cox ◽  
T. Martin Embley

The three-domains tree, which depicts eukaryotes and archaebacteria as monophyletic sister groups, is the dominant model for early eukaryotic evolution. By contrast, the ‘eocyte hypothesis’, where eukaryotes are proposed to have originated from within the archaebacteria as sister to the Crenarchaeota (also called the eocytes), has been largely neglected in the literature. We have investigated support for these two competing hypotheses from molecular sequence data using methods that attempt to accommodate the across-site compositional heterogeneity and across-tree compositional and rate matrix heterogeneity that are manifest features of these data. When ribosomal RNA genes were analysed using standard methods that do not adequately model these kinds of heterogeneity, the three-domains tree was supported. However, this support was eroded or lost when composition-heterogeneous models were used, with concomitant increase in support for the eocyte tree for eukaryotic origins. Analysis of combined amino acid sequences from 41 protein-coding genes supported the eocyte tree, whether or not composition-heterogeneous models were used. The possible effects of substitutional saturation of our data were examined using simulation; these results suggested that saturation is delayed by among-site rate variation in the sequences, and that phylogenetic signal for ancient relationships is plausibly present in these data.


Phytotaxa ◽  
2021 ◽  
Vol 514 (3) ◽  
pp. 247-260
Author(s):  
KASUN THAMBUGALA ◽  
DINUSHANI DARANAGAMA ◽  
SAGARIKA KANNANGARA ◽  
THENUKA KODITUWAKKU

Endophytic fungi are a diverse group of microorganisms that live asymptomatically in healthy tissues of host and they have been reported from all kinds of plant tissues such as leaves, stems, roots, flowers, and fruits. In this study, fungal endophytes associated with tea leaves (Camellia sinensis) were collected from Kandy, Kegalle, and Nuwara Eliya districts in Sri Lanka and were isolated, characterized, and identified. A total of twenty endophytic fungal isolates belonging to five genera were recovered and ITS-rDNA sequence data were used to identify them. All isolated endophytic fungal strains belong to the phylum Ascomycota and the majority of these isolates were identified as Colletotrichum species. Phyllosticta capitalensis was the most commonly found fungal endophyte in tea leaves and was recorded in all three districts where the samples were collected. This is the very first investigation on fungal endophytes associated with C. sinensis in Sri Lanka based on molecular sequence data. In addition, a comprehensive account of known endophytic fungi reported worldwide on Camellia sinensis is provided.


Mammalia ◽  
2019 ◽  
Vol 83 (2) ◽  
pp. 180-189 ◽  
Author(s):  
Adam W. Ferguson ◽  
Houssein R. Roble ◽  
Molly M. McDonough

AbstractThe molecular phylogeny of extant genets (Carnivora, Viverridae,Genetta) was generated using all species with the exception of the Ethiopian genetGenetta abyssinica. Herein, we provide the first molecular phylogenetic assessment ofG. abyssinicausing molecular sequence data from multiple mitochondrial genes generated from a recent record of this species from the Forêt du Day (the Day Forest) in Djibouti. This record represents the first verified museum specimen ofG. abyssinicacollected in over 60 years and the first specimen with a specific locality for the country of Djibouti. Multiple phylogenetic analyses revealed conflicting results as to the exact relationship ofG. abyssinicato otherGenettaspecies, providing statistical support for a sister relationship to all other extant genets for only a subset of mitochondrial analyses. Despite the inclusion of this species for the first time, phylogenetic relationships amongGenettaspecies remain unclear, with limited nodal support for many species. In addition to providing an alternative hypothesis of the phylogenetic relationships among extant genets, this recent record provides the first complete skeleton of this species to our knowledge and helps to shed light on the distribution and habitat use of this understudied African small carnivore.


2013 ◽  
Vol 58 (4) ◽  
Author(s):  
Kurt Galbreath ◽  
Kristina Ragaliauskaite ◽  
Leonas Kontrimavichus ◽  
Arseny Makarikov ◽  
Eric Hoberg

AbstractHymenolepidid cestodes in Myodes glareolus from Lithuania and additional specimens originally attributed to Arostrilepis horrida from the Republic of Belarus are now referred to A. tenuicirrosa. Our study includes the first records of A. tenuicirrosa from the European (western) region of the Palearctic, and contributes to the recognition of A. horrida (sensu lato) as a complex of cryptic species distributed broadly across the Holarctic. Specimens of A. tenuicirrosa from Lithuania were compared to cestodes representing apparently disjunct populations in the eastern Palearctic based on structural characters of adult parasites and molecular sequence data from nuclear (ITS2) and mitochondrial (cytochrome b) genes. Morphological and molecular data revealed low levels of divergence between eastern and western populations. Phylogeographic relationships among populations and host biogeographic history suggests that limited intraspecific diversity within A. tenuicirrosa may reflect a Late Pleistocene transcontinental range expansion from an East Asian point of origin.


Phytotaxa ◽  
2014 ◽  
Vol 189 (1) ◽  
pp. 186 ◽  
Author(s):  
JOEL A. MERCADO-DÍAZ ◽  
ROBERT LÜCKING ◽  
SITTIPORN PARNMEN

Two new genera and twelve new species of Graphidaceae are described from Puerto Rico. The two new genera, Borinquenotrema and Paratopeliopsis, are based on a combination of molecular sequence data and phenotype characters. Borinquenotrema, with the single new species B. soredicarpum, features rounded ascomata developing beneath and persistently covered with soralia and with an internal anatomy reminescent of Carbacanthographis; it is close to the  tribe Ocellularieae. Paratopeliopsis, including the single new species P. caraibica, resembles a miniature Topeliopsis but differs in the distinctly farinose thallus and the small, brown ascospores; it is not closely related to the latter genus but belongs in tribe Thelotremateae. The other ten new species belong in the genera Acanthotrema, Clandestinotrema, Compositrema, Fissurina, Ocellularia, and Thalloloma. Acanthotrema alboisidiatum is closely related to A. brasilianum but differs in the short, white isidia resembling insect eggs. Clandestinotrema portoricense has a unique ascospore type with a longitudinal septum only in the proximal cell. Compositrema borinquense resembles a species of Stegobolus but belongs in Compositrema based on sequence data, and is characterized by ascomata with a unique columella composed of thick, irregularly radiating strands. The second new species in this genus, C. isidiofarinosum, differs by its ecorticate, farinose thallus with scattered, corticate isidia and by its small ascomata with inconspicuous columella. The three new species of Fissurina all have 3-septate ascospores and are otherwise characterized by an isidiate thallus and stellate, orange-yellow lirellae (F. aurantiacostellata), a verrucose thallus strongly encrusted with calcium oxalate crystals and white, irregularly branched lirellae (F. crystallifera), and myriotremoid ascomata arranged in short lines (F. monilifera). Ocellularia portoricensis belongs in the core group of Ocellularia and differs from O. cavata in the white medulla and the larger ascospores becoming brown, whereas O. vulcanisorediata produces prominent soralia and immersed ascomata with apically carbonized excipulum and columella and small, transversely septate, hyaline ascospores; it is closely related to O. conformalis. Finally, Thalloloma rubromarginatum resembles T. haemographum in the brownish lirellae with bright red margin but differs from that and other species in the corticate thallus and the norstictic acid chemistry. The new combination Ampliotrema rimosum (Hale) Mercado-Díaz, Lücking & Parnmen is also proposed. Considering the current biodiversity knowledge on this family, the high level of endemism observed in other groups of organisms in the island, and the relatively high number of Graphidaceae described, it is highly likely that at least some of these new taxa are endemic to the island. This view is further supported by the unique features of several of the new species, representing novel characters in the corresponding genera.


2009 ◽  
Vol 170 (12) ◽  
pp. 1455-1463 ◽  
Author(s):  
W. M. van Ballegooijen ◽  
R. van Houdt ◽  
S. M. Bruisten ◽  
H. J. Boot ◽  
R. A. Coutinho ◽  
...  

Zootaxa ◽  
2021 ◽  
Vol 4920 (2) ◽  
pp. 151-199
Author(s):  
HIROSHI KAJIHARA

The nemertean order Monostilifera consists of 594 species in 127 genera and is distributed worldwide. Within the Monostilifera, two suborders have been recognized, Cratenemertea and Eumonostilifera. Within the latter, two, unranked clade names, Oerstediina and Amphiporina, were recently proposed without formal taxonomic definition. In this article, I give morphological circumscriptions and clade definitions for Cratenemertea, Eumonostilifera, Oerstediina, Plectonemertidae, Oerstediidae, and Amphiporina. Oerstediina and Amphiporina are placed on the Linnaean rank of infraorder. Constituent genera and species for each higher taxon are tabulated. The genus Amphiporella Friedrich, 1939 is herein replaced with Germanemertes nom. nov. to avoid homonymy with the Carboniferous fossil bryozoan genus Amphiporella Girty, 1910. Loxorrhochmidae Diesing, 1862 is declared a nomen oblitum relative to Tetrastemmatidae Hubrecht, 1897, a nomen protectum under Article 23.9 of the International Code of Zoological Nomenclature. There remain 308 species of eumonostiliferans whose infraorder affiliation is uncertain due to the lack of information on vascular morphology and molecular sequence data. The suborder affiliation of the two species Cinclidonemertes mooreae Crandall, 2010 and Verrillianemertes schultzei Senz, 2001 is left uncertain.  


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