scholarly journals Use of nuclear genes for phylogeny reconstruction in plants

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.

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.


Phytotaxa ◽  
2017 ◽  
Vol 323 (1) ◽  
pp. 27 ◽  
Author(s):  
VLADIMIR E. FEDOSOV ◽  
ALINA V. FEDOROVA ◽  
ELENA A. IGNATOVA ◽  
MICHAEL S. IGNATOV

The genus Seligeria is revised based on morphological and DNA sequence data of nuclear ITS and chloroplastic trnL-F. Fifteen species from most infrageneric units of the genus are recovered in two well supported phylogenetic clusters that are also distinctive in morphology. The clade with the type species of the genus, S. pusilla, includes also S. donniana, S. brevifolia, S. calcarea, S. patula, S. tristichoides, S. trifaria, and S. oelandica. These species are characterized by short, cupulate or turbinate capsules widened towards the mouth, and the lack of a stem central strand. Another clade includes species with rather long, mainly ovate to cylindrical capsules and more or less developed stem central strand: S. campylopoda, S. recurvata, S. subimmersa, S. diversifolia, and S. polaris. These two clusters do not show sister relationships, but the second one appears more closely related to the Blindia clade. To resolve the apparent paraphyly, the latter phylogenetic group is segregated in a genus Blindiadelphus. In some aspects of morphology and ecology it is intermediate between Seligeria s. str. and Blindia, but differs from both genera in subquadrate upper leaf cells and thin- to moderately thick-walled rectangular exothecial cells. Molecular phylogenetic analyses revealed heterogeneity within the specimens previously referred to Blindiadelphus campylopodus, indicating a presence in Asian Russia of an undescribed species that is described here as Blindiadelphus sibiricus. It differs from B. campylopodus by the larger spores and typically rounded leaf apices. The isotype specimen of S. galinae appeared to be nearly identical to S. donniana in the sequences of ITS and trnL-F, and examination of morphology revealed no substantial differences between these species. Thus, we consider S. galinae as a synonym of S. donniana. The genus Blindiadelphus includes species of Seligeria subg. Blindiadelphus and S. subg. Cyrtoseligeria, which however are found intermingled in the molecular phylogenetic analysis. Thus the genus Blindiadelphus is accepted without any infrageneric taxa. The phylogenetic tree is congruent with the subdivision of the genus Seligeria s.str into subg. Seligeria, subg. Anodon, subg. Megalosporia and one newly established subgenus Robustidontia for S. brevifolia.


2001 ◽  
Vol 20 (2) ◽  
pp. 183-183 ◽  
Author(s):  
Martin R. Langer

Abstract. Comparative studies on DNA nucleotide sequences have revolutionized our understanding of the phylogenetic relationships of many organisms and have become an important tool in evolutionary, ecological and palaeobiological inquiry. We have analysed partial small-subunit 18S sequences (srDNA) of Elphidium williamsoni (Haynes, 1973), a common intertidal benthic foraminiferid from the North Sea. The molecular phylogenetic analysis of the ribosomal rDNA sequence data indicate that E. williamsoni constitutes a well-defined genetic entity that is closely related to Elphidium aculeatum.Elphidium williamsoni is a prominent and frequently encountered foraminiferid in the North Sea and other tidal flats. It was originally described by Williamson (1858) as Polystomella umbilicata and subsequently renamed by Haynes (1973). Because of its phenotypic similarities with other elphidiids, this species has been frequently confused with, for example E. excavatum or Cribrononion alvarezianum (see Haynes for discussion). The molecular data provided here, and their direct comparison to other benthic foraminifera including one elphidiid, may therefore provide additional insight into the taxonomic status and the validity of this species.Individuals of the foraminiferid Elphidium williamsoni were collected in October 1997 from the intertidal mud flats of the Crildumersiel at the outer Jade Bay near Wilhelmshaven, North Sea (see Langer et al., 1989 for details). The mud flats are characterized by fine-grained, muddy sediments containing high contents of organic material. In the laboratory, specimens were transferred into petri dishes, examined and cleaned under a stereo microscope. Living specimens of E. williamsoni were picked out separately and placed into clean glass dishes containing filtered. . .


IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ondřej Koukol ◽  
Gregorio Delgado

ABSTRACTRecent progress in the discovery of fungal diversity has been enabled by intensive mycological surveys in centres of global biodiversity. Descriptions of new fungal species have been almost routinely based on phenotypic studies coupled with single or multigene phylogenetic analyses of DNA sequence data. However, high accessibility of sequencing services together with an increasing amount of available molecular data are providing easier and less critical support for taxonomic novelties without carefully studying the phenotype, particularly morphology. As a result, the accelerated rate of species descriptions has been unfortunately accompanied by numerous cases of overlooking previously described and well documented species, some of them that have been known for more than a century. Here, we critically examined recent literature, phenotypic and molecular data, and detected multiple issues with putative novelties of asexual Ascomycota traditionally known as hyphomycetes. In order to fix these taxonomic problems, three new combinations within the genera Pleopunctum, Camposporium and Sporidesmium, and two new names in Camposporium are proposed. Moreover, three genera, Aquidictyomyces, Fusiconidium and Pseudohelminthosporium, together with nine species are reduced to synonymy. The examples outlined here clearly show the relevance of morphology in modern phylogenetic studies and the importance of more stringent ‘quality controls’ during biodiversity studies documenting the extensive fungal diversity in a speedy manner.


Phytotaxa ◽  
2016 ◽  
Vol 263 (2) ◽  
pp. 98 ◽  
Author(s):  
JULIA FERM ◽  
JESPER KÅREHED ◽  
BIRGITTA BREMER ◽  
SYLVAIN G. RAZAFIMANDIMBISON

The Malagasy genus Carphalea (Rubiaceae) consists of six species (C. angulata, C. cloiselii, C. kirondron, C. linearifolia, C. madagascariensis, C. pervilleana) of shrubs or small trees and is recognizable by a distinctly lobed calyx, 2(–4)-locular ovaries, each locule with several ovules on a rod-like stalk arising from the base of the locule, and indehiscent fruits. Carphalea linearifolia, rediscovered in 2010, has not previously been included in any Rubiaceae molecular phylogenetic studies. We re-investigated the monophyly of Carphalea using sequence data from chloroplast (rps16 and trnT-F) and nuclear (ITS and ETS) markers analysed with parsimony and Bayesian methods. Carphalea linearifolia forms a clade with C. cloiselii and the type species C. madagascariensis. This clade is sister to a clade consisting of the rest of the Carphalea species plus the genus Triainolepis. According to these results, the new genus Paracarphalea is here described to accommodate Carphalea angulata, C. kirondron, and C. pervilleana. The conservation status of Carphalea linearifolia is assessed as critically endangered according to IUCN criteria.


2009 ◽  
Vol 34 (3) ◽  
pp. 580-594 ◽  
Author(s):  
Anthony R. Magee ◽  
Ben-Erik van Wyk ◽  
Patricia M. Tilney ◽  
Stephen R. Downie

Generic circumscriptions and phylogenetic relationships of the Cape genera Capnophyllum, Dasispermum, and Sonderina are explored through parsimony and Bayesian inference analyses of nrDNA ITS and cpDNA rps16 intron sequences, morphology, and combined molecular and morphological data. The relationship of these genera with the North African genera Krubera and Stoibrax is also assessed. Analyses of both molecular data sets place Capnophyllum, Dasispermum, Sonderina, and the only southern African species of Stoibrax (S. capense) within the newly recognized Lefebvrea clade of tribe Tordylieae. Capnophyllum is strongly supported as monophyletic and is distantly related to Krubera. The monotypic genus Dasispermum and Stoibrax capense are embedded within a paraphyletic Sonderina. This complex is distantly related to the North African species of Stoibrax in tribe Apieae, in which the type species, Stoibrax dichotomum, occurs. Consequently, Dasispermum is expanded to include both Sonderina and Stoibrax capense. New combinations are formalized for Dasispermum capense, D. hispidum, D. humile, and D. tenue. An undescribed species from the Tanqua Karoo in South Africa is also closely related to Capnophyllum and the Dasispermum–Sonderina complex. The genus Scaraboides is described herein to accommodate the new species, S. manningii. This monotypic genus shares the dorsally compressed fruit and involute marginal wings with Capnophyllum, but is easily distinguished by its erect branching habit, green leaves, scabrous umbels, and fruit with indistinct median and lateral ribs, additional solitary vittae in each marginal wing, and parallel, closely spaced commissural vittae. Despite the marked fruit similarities with Capnophyllum, analyses of DNA sequence data place Scaraboides closer to the Dasispermum–Sonderina complex, with which it shares the erect habit, green (nonglaucous) leaves, and scabrous umbels.


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.


Phytotaxa ◽  
2014 ◽  
Vol 161 (2) ◽  
pp. 157 ◽  
Author(s):  
Sinang Hongsanan ◽  
Putarak Chomnunti ◽  
Pedro W. Crous ◽  
Ekachai Chukeatirote ◽  
Kevin D. Hyde

The order Microthyriales comprises foliar biotrophs, epiphytes, pathogens or saprobes that occur on plant leaves and stems. The order is relatively poorly known due to limited sampling and few in-depth studies. There is also a lack of phylogenetic data for these fungi, which form small black spots on plant host surfaces, but rarely cause any damage to the host. A "Microthyriaceae"-like fungus collected in central Thailand is described as a new genus, Chaetothyriothecium (type species Chaetothyriothecium elegans sp. nov.). Phylogenetic analyses of LSU gene data showed this species to cluster with other members of Microthyriales, where it is related to Microthyrium microscopicum the type of the order. The description of the new species is supplemented by DNA sequence data, which resolves its placement in the order. Little molecular data is available for this order, stressing the need for further collections and molecular data.


2014 ◽  
Vol 62 (3) ◽  
pp. 235 ◽  
Author(s):  
S. Safaei Chaei Kar ◽  
F. Ghanavati ◽  
M. R. Naghavi ◽  
H. Amirabadi-zade ◽  
R. Rabiee

Onobrychis, comprising more than 130 species, is a genus of the family Fabaceae. At this time, the interspecies relationship of this biologically important genus is still a subject of great discussion and debate. To help resolve this disagreement, we used molecular phylogeny to analyse internal transcribed spacer (ITS) and trnL–trnF sequences of 76 species of Onobrychis. Bayesian interference, maximum parsimony and maximum likelihood analyses of nuclear ITS and plastid trnL–trnF DNA sequence data generated trees with strong posterior probability for two groups: Onobrychis subgen. Sisyrosema (including: Heliobrychis, Hymenobrychis, Afghanicae and Anthyllium sections) along with Laxiflorae section in Group I and Onobrychis subgen. Onobrychis (except Laxiflorae section) in the other (Group II). The Laxiflorae section roots back to the ancestral node for Sisyrosema subgen. O. viciifolia (cultivated species), which is closely associated with O. cyri var. cyri, suggesting that the latter may be a wild progenitor of O. viciifolia. The present study supported the paraphyly of subgenera Onobrychis and Sisyrosema. The study proposed the paraphyletic nature of the sections Onobrychis, Dendrobrychis, Heliobrychis and Hymenobrychis. Together with our molecular phylogenetic analyses we present a review of Onobrychis morphology and discuss and compare our results with those of earlier morphological and molecular phylogenetic analyses.


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.


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