Molecular phylogenetic relationships of Metastrongylus nematodes with emphasis on specimens from domestic pigs in Vietnam

2021 ◽  
Vol 95 ◽  
Author(s):  
N.V. Tuyen ◽  
N.T.K. Lan ◽  
P.N. Doanh

Abstract Lungworms of the genus Metastrongylus are parasitic nematodes in the respiratory tract of swine. Although they infect both wild boars and domestic pigs, studies on Metastrongylus infections in wild boars in Europe, the Americas and Africa are numerous, while those in domestic pigs are few. There are several studies analysing the molecular phylogenetic relationships of few individual Metastrongylus species with other nematode taxa, but there are no studies on the phylogenetic relationships of species within the genus Metastrongylus. In Southeast Asia, reports on swine lungworms are extremely scarce and do not include any nucleotide sequence data. Therefore, the aim of the present study is to survey Metastrongylus infection in domestic pigs raised in Dien Bien Province, Northern Vietnam, and to analyse the molecular phylogenetic relationships of Metastrongylus species. Based on morphological and molecular data, we identified two species: Metastrongylus apri and Metastrongylus pudendotectus. The prevalence of the former species was found to be significantly higher than the latter one (24.1% vs. 2.3%). We observed pigs exhibiting a coinfection with the two lungworm species or a single infection with only M. apri. However, we did not observe any pigs being infected with just M. pudendotectus. Vietnamese Metastrongylus specimens showed slight morphological and molecular differences compared to those from other countries. The molecular analyses revealed a close genetic relationship between M. apri and Metastrongylus salmi, while both these species were far distant from M. pudendotectus. The present study highlights the needs for further studies to clarify the morphological features and ecological and phylogenetic relationships of Metastrongylus species at the global scale.

2017 ◽  
Vol 39 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Nguyen Thi Huong Giang ◽  
Tran Duc Hoan ◽  
Nguyen Thi Thu Huyen ◽  
Nguyen Thi Kim Lan ◽  
Pham Ngoc Doanh

The genus Strongyloides is a group of parasitic nematodes of vertebrates comprised of over 50 species. A large numbers of nucleotide sequences of Strongyloides species have been deposited in GenBank. The vast majority of them are of Strongyloides from human beings, non-human primates, rats and cattle, but there are few molecular data of Strongyloides species isolated from pigs. The aim of this study is to identify Strongyloides species collected from pigs from Bac Giang Province, Vietnam, and analyze their molecular phylogenetic relationship within the genus Strongyloides based on 18S rDNA sequences. The morphological and molecular analyses revealed that the Strongyloides samples collected from pigs from Bac Giang Province, Vietnam, were in fact S. ransomi. The 18S rDNA sequences of S. ransomi from Vietnam were completely identical with that from Cambodia, but slightly different (0.3%) from that of Japan. In comparison to other Strongyloides species, S. ransomi was genetically close to S. venezuelensis. Citation: Nguyen Thi Giang, Tran Duc Hoan, Nguyen Thi Thu Huyen, Nguyen Thi Kim Lan, Phạm Ngọc Doanh, 2017. Morphological and molecular characterisation of Strongyloides ransomi (Nematoda: Strongyloididae) collected from domestic pigs in Bac Giang province, Vietnam. Tap chi Sinh hoc, 39(3): 270- 275. DOI: 10.15625/0866-7160/v39n3.10796.*Corresponding author: [email protected] 18 May 2017, accepted 20 August 2017 


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.


Zootaxa ◽  
2021 ◽  
Vol 5052 (3) ◽  
pp. 353-379
Author(s):  
JULIO C.C. FERNANDEZ ◽  
MARIANELA GASTALDI ◽  
GERMÁN ZAPATA-HERNÁNDEZ ◽  
LUIS M. PARDO ◽  
FABIANO L. THOMPSON ◽  
...  

Here, we describe four new species of Crellidae Dendy, 1922 and discuss characters and relationships from published molecular phylogenies including crellid sponges. New species proposed are Crella (Pytheas) chiloensis Fernandez, Gastaldi, Pardo & Hajdu, sp. nov., from southern Chile (15 m depth), C. (P.) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu, sp. nov., from Desventuradas Archipelago (10–20 m depth), Crella (P.) santacruzae Fernandez, Gastaldi, Thompson & Hajdu, sp. nov., from deep waters off Argentina (750 m depth) and Crellomima sigmatifera Fernandez, Gastaldi & Hajdu, sp. nov., from the Chilean fjords region (ca. 20 m depth). These new species are set apart from each other and from known species mainly due to aspects of their spiculation. Chelae microscleres and acanthostyles supply characters that might be used to infer phylogenetic relationships and to verify the monophyly of Crella Gray, 1867 and Crellidae, which has seemingly been contradicted by preliminary molecular data available in the systematics’ literature. Our own interpretation of phylogenetic affinities, in the light of morphological characters from previous taxonomic studies, argues for a classification reassessment of materials (vouchers) included in these molecular phylogenies, especially in the case of Crella incrustans (Carter, 1885). We argue that currently available molecular phylogenetic outcomes for crellid sponges are not supportive of the polyphyly of Crella and Crellidae.  


Nematology ◽  
2002 ◽  
Vol 4 (5) ◽  
pp. 615-625 ◽  
Author(s):  
Steven Nadler

AbstractPractitioners of nematode taxonomy have rarely been explicit about what species represent or how data are being used to delimit species prior to their description. This lack of explicitness reflects the broader species problem common to all biology: there is no universally accepted idea of what species are and, as a consequence, scientists disagree on how to go about finding species in nature. However, like other biologists, nematologists seem to agree that species are real and discrete units in nature, and that they result from descent with modification. This evolutionary perspective provides a conceptual framework for nematologists to view species as independent evolutionary lineages, and provides approaches for their delimitation. Specifically, species may be delimited scientifically by methods that can test the hypothesis of lineage independence. For sequence data, such hypothesis testing should be based on sampling many individual organisms for multiple loci to avoid mistaking tokogeny and gene trees as evidence of species. Evolutionary approaches to analysing data and delimiting species avoid the inherent pitfalls in approaches that use all observed sequence differences to define species through calculation of a genetic distance. To illustrate evolutionary species delimitation, molecular data are used to test the hypothesis that hookworms parasitic in northern fur seals and in California sea lions represent separate species. The advantages and potential caveats of employing nucleotide sequence data for species delimitation are discussed, and the merits of evolutionary approaches are contrasted to inherent problems in similarity-based methods.


2016 ◽  
Vol 48 (5) ◽  
pp. 387-421 ◽  
Author(s):  
Daphne F. STONE ◽  
James W. HINDS ◽  
Frances L. ANDERSON ◽  
James C. LENDEMER

AbstractA revision of the North American members of the Leptogium saturninum group (i.e. species with long lower-surface hairs, isidia, and usually smooth upper surface) is presented based on molecular phylogenetic analyses of mtSSU and nrITS sequence data, together with an extensive morphological study. Three species supported by both molecular and morphological characteristics are recognized: L. acadiense sp. nov. (distinguished by granular saturninum-type isidia, medulla composed of irregularly arranged or perpendicular hyphae), L. cookii sp. nov. (distinguished by cylindrical saturninum-type isidia) and L. hirsutum (distinguished by hirsutum-type isidia and medulla composed of loosely intertwined hyphae). One species supported by morphological characteristics, but for which no molecular data could be generated, is also recognized: L. compactum sp. nov. (distinguished by hirsutum-type isidia and medulla composed of tightly packed hyphae). Finally, L. saturninum (distinguished by granular saturninum-type isidia and medulla composed of perpendicular and parallel hyphae) is supported by morphological characteristics but molecular data from geographically diverse populations, including those near the type locality, indicate that the morphologically defined species is paraphyletic. Leptogium burnetiae is excluded from North American based on morphological study of the type. The species are described and illustrated in detail, and are distinguished morphologically by their isidium development, morphology of mature isidia, and pattern of hyphae in the medulla in transverse sections near lobe margins. A key to the members of the L. saturninum group and related species is also presented.


Phytotaxa ◽  
2018 ◽  
Vol 350 (1) ◽  
pp. 42 ◽  
Author(s):  
GALINA V. DEGTJAREVA ◽  
MICHAEL G. PIMENOV ◽  
TAHIR H. SAMIGULLIN

The systematic position of three Apiaceae-Apioideae taxa, Pinacantha porandica, Ladyginia bucharica and Peucedanum mogoltavicum, from Middle Asia and Afghanistan, is clarified based on nrITS DNA sequence data. In the molecular phylogenetic tree, the monotypic Pinacantha is placed in unresolved position within the Ferulinae. Although there is no morphological information on essential characters, we propose a new position of Pinacantha porandica within the genus Ferula. As a result a new combination Ferula porandica is proposed, with a new section Pinacantha to accommodate it. The attribution of Peucedanum mogoltavicum to Ferula has been confirmed, its correct name being Ferula lithophila. The genus Ladyginia should not be included in Ferula, its closest relatives being Mozaffariania and Glaucosciadium from the Glaucosciadium Clade.


Paleobiology ◽  
1994 ◽  
Vol 20 (3) ◽  
pp. 259-273 ◽  
Author(s):  
Andrew B. Smith ◽  
D. T. J. Littlewood

Molecular data are becoming an indispensable tool for the reconstruction of phylogenies. Fossil molecular data remain scarce, but have the potential to resolve patterns of deep branching and provide empirical tests of tree reconstruction techniques. A total evidence approach, combining and comparing complementary morphological, molecular and stratigraphical data from both recent and fossil taxa, is advocated as the most promising way forward because there are several well-established problems that can afflict the analysis of molecular sequence data sometimes resulting in spurious tree topologies. The integration of evidence allows us to: (1) choose suitable taxa for molecular phylogenetic analysis for the question at hand; (2) discriminate between conflicting hypotheses of taxonomic relationship and phylogeny; (3) evaluate procedures and assumptions underlying methods of building trees; and (4) estimate rates of molecular evolution in the geological past. Paleontology offers a set of independent data for comparison and corroboration of analyses and provides the only direct means of calibrating molecular trees, thus giving insight into rates of molecular evolution in the geological past.


2004 ◽  
Vol 17 (2) ◽  
pp. 145 ◽  
Author(s):  
Randall L. Small ◽  
Richard C. Cronn ◽  
Jonathan F. Wendel

Molecular data have had a profound impact on the field of plant systematics, and the application of DNA-sequence data to phylogenetic problems is now routine. The majority of data used in plant molecular phylogenetic studies derives from chloroplast DNA and nuclear rDNA, while the use of low-copy nuclear genes has not been widely adopted. This is due, at least in part, to the greater difficulty of isolating and characterising low-copy nuclear genes relative to chloroplast and rDNA sequences that are readily amplified with universal primers. The higher level of sequence variation characteristic of low-copy nuclear genes, however, often compensates for the experimental effort required to obtain them. In this review, we briefly discuss the strengths and limitations of chloroplast and rDNA sequences, and then focus our attention on the use of low-copy nuclear sequences. Advantages of low-copy nuclear sequences include a higher rate of evolution than for organellar sequences, the potential to accumulate datasets from multiple unlinked loci, and bi-parental inheritance. Challenges intrinsic to the use of low-copy nuclear sequences include distinguishing orthologous loci from divergent paralogous loci in the same gene family, being mindful of the complications arising from concerted evolution or recombination among paralogous sequences, and the presence of intraspecific, intrapopulational and intraindividual polymorphism. Finally, we provide a detailed protocol for the isolation, characterisation and use of low-copy nuclear sequences for phylogenetic studies.


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