Phylogeny of Trematomus (Notothenioidei: Nototheniidae) inferred from mitochondrial and nuclear gene sequences

2009 ◽  
Vol 21 (6) ◽  
pp. 565-570 ◽  
Author(s):  
Kristen L. Kuhn ◽  
Thomas J. Near

AbstractThe biota of Antarctica is amazingly rich and highly endemic. The phylogenetics of notothenioid fishes has been extensively investigated through analyses of morphological characters, DNA sequences from mitochondrial genes, and single copy nuclear genes. These phylogenetic analyses have produced reasonably similar phylogenetic trees of notothenioids, however a number of phylogenetic questions remain. The nototheniid clade Trematomus is an example of a group where phylogenetic relationships remain unresolved. In this paper we revisit the phylogenetic relationships of Trematomus using both increased taxon sampling and an expanded dataset which includes DNA sequences from two mitochondrial genes (ND2 and 16S rRNA) and one single-copy nuclear gene (RPS7). The Bayesian phylogeny resulting from the analysis of the combined mitochondrial and nuclear gene datasets was well resolved and contained more interspecific nodes supported with significant Bayesian posteriors than either the mitochondrial or nuclear gene phylogenies alone. This demonstrates that the addition of nuclear gene sequence data to mitochondrial data can enhance phylogenetic resolution and increase node support. Additionally, the results of the combined mitochondrial and nuclear Bayesian analyses provide further support for the inclusion of species previously classified as Pagothenia and Cryothenia in Trematomus.

2021 ◽  
Author(s):  
◽  
Whitney L M Bouma

<p>The fern family Pteridaceae is among the largest fern families in New Zealand. It comprises 17 native species among five genera. Traditionally the classification of Pteridaceae was based on morphological characters. The advent of molecular technology, now makes is possible to test these morphology-based classifications. The Pteridaceae has previously been subjected to phylogenetic analyses; however representatives from New Zealand and the South Pacific have never been well represented in these studies. This thesis research aimed to investigate the phylogenetic relationships of the New Zealand Pteridaceae, as well as, the phylogenetic relationships of the New Zealand species to their overseas relatives. The DNA sequences of several Chloroplast loci (e.g. trnL-trnF locus, rps4 and rps4-trnS IGS, atpB, and rbcL) were determined and the phylogenetic relationships of the New Zealand Pteridaceae and several species-specific question within the genus Pellaea and Adiantum were investigated. Results presented in this thesis confirm previously published phylogenetics of the Pteridaceae, which show the resolution of five major clades, i.e.,cryptogrammoids, ceratopteridoids, pteridoids, cheilanthoids, and the adiantoids. The addition of the New Zealand species revealed a possible South West Pacific groups formed by the respective genera, where New Zealand species were generally more related to one another than to overseas relatives. Within the New Zealand Pellaea, the analysis of the trnL-trnF locus sequence data showed that the morphologically-intermediate plants P. aff. falcata, responsible for taxonomic confusion, were more closely related to P. rotundifolia than to P. falcata. Furthermore, the species collected on the Kermadec Islands, previously thought to be P. falcata, are genetically distinct from the Australian P. falcata and they could constitute a new species. Adiantum hispidulum, which is polymorphic for two different hair types being used to distinguish them as different species, was also reinvestigated morphologically and molecularly. Morphological inspection of hairs revealed three hair types as opposed to the previous thought two, and furthermore, they correspond to three different trnL-trnF sequences haplotypes.</p>


2008 ◽  
Vol 39 (4) ◽  
pp. 431-460 ◽  
Author(s):  
Jakob Damgaard

AbstractThe phylogeny of semi-aquatic bugs (Hemiptera-Heteroptera: Gerromorpha) was tested in parsimony analyses of 64 morphological characters and approximately 2.5 kb of DNA sequence data from the mitochondrial genes encoding COI+II and 16SrRNA and the nuclear gene encoding 28SrRNA. The taxon sample included representatives of all families and most subfamilies of Gerromorpha and a selection of outgroup taxa representing the two basal infraorders of Heteroptera, Enicocephalomorpha and Dipsocoromorpha, and two families of Nepomorpha. A simultaneous analysis (SA) of all data, and with gaps scored as fifth state characters, gave a single most parsimonious tree with all families resolved as monophyletic, except the Veliidae, where Microveliinae + Haloveliinae, Veliinae, Rhagoveliinae, Perittopinae, and Ocelloveliinae were resolved as successive sister groups to the Gerridae, thus confirming earlier statements about paraphyly of this family. The Gerridae + Veliidae clade was strongly supported, but otherwise only the Gerridae + Veliidae less Ocelloveliinae and the Gerridae itself had support. These three clades could all be diagnosed on apomorphic morphological characters, although no characters diagnosing the Gerridae were without convergences or present in all included taxa. While the Ocelloveliinae, Veliinae and Haloveliinae could not be diagnosed on convincing apomorphies, the Microveliinae + Haloveliinae, and their sister group relationship with the Gerridae, could be diagnosed on rather strong morphological synapomorphies, suggesting that Gerridae could be expanded to include these two veliid subfamilies, while Ocelloveliinae, and perhaps the remaining veliid subfamilies, could be elevated to new families. In Gerridae, the Ptilomerinae + Halobatinae was sister group to all other subfamilies, while the Rhagadotarsinae + Trepobatinae was sister group to a clade comprising the Gerrinae, Eotrechinae, Cylindrostethinae and Charmatometrinae. Most relationships in this clade were poorly supported and diagnosed, and Cylindrostethinae was surprisingly found to be paraphyletic. The sister group to the Gerridae + Veliidae clade was a strongly supported clade comprising the Paraphrynoveliidae and Macroveliidae, and this, and the lack of convincing synapomorphies for Paraphrynoveliidae, suggest that these two small families could be synonymized. For the basal relationships of Gerromorpha, the Mesoveliidae was strongly supported sister group to all other families, while the Hebridae, Hermatobatidae and Hydrometridae formed a poorly supported and poorly diagnosed sister group to the Gerridae + Veliidae + Paraphrynoveliidae + Macroveliidae clade. The unexpected sister group relationship between Hermatobatidae and Hydrometridae was moderately supported, and could be diagnosed on two synapomorphies, thus giving a new hypothesis about the relationships of these very divergent families. Phylogenetic analyses of individual character partitions gave less resolved and less supported relationships, and the mitochondrial genes COI+II and 16SrRNA contributed negative hidden partitioned Bremer support (HPBS) to the simultaneous analysis tree, probably due to homoplasy caused by saturation effects.


2021 ◽  
Author(s):  
◽  
Whitney L M Bouma

<p>The fern family Pteridaceae is among the largest fern families in New Zealand. It comprises 17 native species among five genera. Traditionally the classification of Pteridaceae was based on morphological characters. The advent of molecular technology, now makes is possible to test these morphology-based classifications. The Pteridaceae has previously been subjected to phylogenetic analyses; however representatives from New Zealand and the South Pacific have never been well represented in these studies. This thesis research aimed to investigate the phylogenetic relationships of the New Zealand Pteridaceae, as well as, the phylogenetic relationships of the New Zealand species to their overseas relatives. The DNA sequences of several Chloroplast loci (e.g. trnL-trnF locus, rps4 and rps4-trnS IGS, atpB, and rbcL) were determined and the phylogenetic relationships of the New Zealand Pteridaceae and several species-specific question within the genus Pellaea and Adiantum were investigated. Results presented in this thesis confirm previously published phylogenetics of the Pteridaceae, which show the resolution of five major clades, i.e.,cryptogrammoids, ceratopteridoids, pteridoids, cheilanthoids, and the adiantoids. The addition of the New Zealand species revealed a possible South West Pacific groups formed by the respective genera, where New Zealand species were generally more related to one another than to overseas relatives. Within the New Zealand Pellaea, the analysis of the trnL-trnF locus sequence data showed that the morphologically-intermediate plants P. aff. falcata, responsible for taxonomic confusion, were more closely related to P. rotundifolia than to P. falcata. Furthermore, the species collected on the Kermadec Islands, previously thought to be P. falcata, are genetically distinct from the Australian P. falcata and they could constitute a new species. Adiantum hispidulum, which is polymorphic for two different hair types being used to distinguish them as different species, was also reinvestigated morphologically and molecularly. Morphological inspection of hairs revealed three hair types as opposed to the previous thought two, and furthermore, they correspond to three different trnL-trnF sequences haplotypes.</p>


2006 ◽  
Vol 55 (1-6) ◽  
pp. 45-52 ◽  
Author(s):  
V. M. Stefenon ◽  
O. Gailing ◽  
R. Finkeldey

Abstract Highly polymorphic AFLP markers were applied to analyse the phylogenetic relationships of seven species from three sections within genus Araucaria (Araucariaceae) with cladistic and phenetic approaches. The objectives of the study were to compare the intrageneric relationships within Araucaria assessed by AFLP markers with the classification according to chloroplast DNA sequences and morphological characters. The AMOVA revealed 48% of the variation among species. The results of the principal coordinate analysis revealed three distinct groups: (1) A. angustifolia and A. araucana (= section Araucaria), (2) A. bidwillii (= section Bunya) and (3) A. cunninghamii, A. heterophylla, A. rulei and A. scopulorum (= section Eutacta). In the cladistic and phenetic analyses, phylogenetic trees were subdivided into two sister clades, one comprising the samples from section Eutacta, the other one was divided again into two sister clades corresponding to sections Araucaria and Bunya. These results are congruent with a previous phylogenetic study of the family Araucariaceae based on rbcL sequences and with the classification of genus Araucaria based on morphological characters. Both rbcL sequence data and AFLP analyses do not support section Bunya as one of the oldest sections within genus Araucaria, as suggested by the fossil record. The utility of AFLP markers for phylogenetic analyses is discussed.


2014 ◽  
Vol 62 (8) ◽  
pp. 638 ◽  
Author(s):  
Farrokh Ghahremaninejad ◽  
Mehrshid Riahi ◽  
Melina Babaei ◽  
Faride Attar ◽  
Lütfi Behçet ◽  
...  

Verbascum is one of the main genera of Scrophulariaceae, but delimitation and phylogenetic relationships of this genus are unclear and have not yet been studied using DNA sequences. Here, using four selected molecular markers (nrDNA ITS and the plastid spacers trnS/G, psbA-trnH and trnY/T), we present a phylogeny of Verbascum and test previous infrageneric taxonomic hypotheses as well as its monophyly with respect to Scrophularia. We additionally discuss morphological variation and the utility of morphological characters as predictors of phylogenetic relationships. Our results show that while molecular data unambiguously support the circumscription of Verbascum inferred from morphology, they prove to be of limited utility in resolving infrageneric relationships, suggesting that Verbascum ‘s high species diversity is due to rapid and recent radiation. Our work provides phylogenetic estimation of the genus Verbascum using molecular data and can serve as a starting point for future investigations of Verbascum and relatives.


2002 ◽  
Vol 33 (4) ◽  
pp. 361-386 ◽  
Author(s):  
Vest Pedersen

AbstractThe phylogenetics of 40 taxa of European bumblebees were analysed based on PCR amplified and direct sequenced DNA from one region of the mitochondrial gene Cytochrome Oxidase I (1046 bp) and for 26 taxa from two regions in the nuclear gene Elongation Factor 1α (1056 bp). The sequences were aligned to the corresponding sequences in the honey bee. Phylogenetic analyses based on parsimony, as well as maximum likelihood, indicate that the bumblebees can be separated into several well-supported clades. Most of the terminal clades correspond very well with the clades known from former phylogenetic analyses based on morphology and recognized as the subgenera: Mendacibombus, Confusibombus, Psithyrus, Thoracobombus, Megabombus, Rhodobombus, Kallobombus, Alpinobombus, Subterraneobombus, Alpigenobombus, Pyrobombus, Bombus and Melanobombus. All the cuckoo bumblebees form a well-supported clade, the subgenus Psithyrus, within the true bumblebees. All the analyses place Kallobombus as the most basal taxon in contradiction to former analyses. The other deeper nodes of the phylogenetic trees, which are weakly supported, deviate significantly from former published trees - especially the trees based on mtCO-I. Presumably, the reasons are that multiple hits and the strong bias of the bases A and T blur the relationships in the deepest part of the trees. Analyses of the region in mtCO-I show a very strong A+T bias (A+T= 75%), which also indicate preferences in the use of codons with A or T in third positions. In closely related entities, there is only a weak transversion bias (A+T). In the studied regions in EF 1-α, no nucleotide bias is observed. The observed differences in bases between the investigated taxa are relatively small and the gene is too conserved to solve all the questions that the analyses of the deeper nodes using mtCO-I raise.


MycoKeys ◽  
2019 ◽  
Vol 56 ◽  
pp. 49-66
Author(s):  
Qin Yang ◽  
Wen-Yan Chen ◽  
Ning Jiang ◽  
Cheng-Ming Tian

To clarify phylogenetic relationships amongst Nectria, Neothyronectria and Thyronectria in Nectriaceae, we examined detailed morphological characters and performed phylogenetic analyses of a concatenated dataset, based on the ITS, LSU, tef1 and tub2 DNA sequences of fungal specimens in China. Four species of nectria-related fungi were identified, i.e. Nectriadematiosa, N.pseudotrichia, Neothyronectriacitri and Thyronectriapinicola. The newly described species, Neothyronectriacitri, is characterised by its ascomatal wall with bright yellow scurf, unitunicate asci, each with 4-spored and ascospores allantoid to short-cylindrical, uniseriate, muriform, hyaline to slightly yellowish-brown. This species has affinities with other one known species of Neothyronectria and can be distinguished by molecular data.


2015 ◽  
Vol 97 (2) ◽  
pp. 394-404 ◽  
Author(s):  
Juan F. Díaz-Nieto ◽  
Sharon A. Jansa ◽  
Robert S. Voss

Abstract Morphological character data are inadequate to resolve the evolutionary relationships of the didelphid genus Chacodelphys , which previous phylogenetic analyses have alternatively suggested might be the sister taxon of Lestodelphys and Thylamys (tribe Thylamyini) or of Monodelphis (tribe Marmosini) in the subfamily Didelphinae. Because fresh material of Chacodelphys is unavailable, we extracted DNA from microscopic fragments of soft tissue adhering to the 95-year-old holotype skull of C. formosa. Phylogenetic analyses of the resulting sequence data convincingly resolve Chacodelphys as the sister taxon of Cryptonanus , a genus with which it had not previously been thought to be closely related. This novel clade ( Chacodelphys + Cryptonanus ) belongs to an unnamed thylamyine lineage with Gracilinanus and Lestodelphys + Thylamys , but relationships among these taxa remain to be convincingly resolved. Los análisis basados en caracteres morfológicos han sido inadecuados para resolver las relaciones evolutivas del género marsupial didélfido Chacodelphys . Previos análisis filogenéticos han sugerido como hipótesis alternativas que Chacodelphys sea el grupo hermano de Lestodelphys y Thylamys (tribu Thylamyini) o de Monodelphis (tribu Marmosini), todos estos géneros pertenecientes a la subfamilia Didelphinae. Debido a la ausencia de material fresco de Chacodelphys , extrajimos ADN de fragmentos microscópicos de tejido adherido al cráneo de 95 años del holotipo de C. formosa . Análisis filogenéticos de las secuencias obtenidas resuelven convincentemente la posición filogenética de Chacodelphys como el taxón hermano de Cryptonanus , un género con el cual nunca antes se había pensado que estuviera cercanamente relacionado. Aunque reconocemos a este nuevo clado ( Chacodelphys + Cryptonanus ) junto con Gracilinanus y Lestodelphys + Thylamys pertenecientes a un linaje sin nombre, las relaciones entre estas taxa siguen sin estar convincentemente resueltas.


Zootaxa ◽  
2011 ◽  
Vol 3001 (1) ◽  
pp. 57 ◽  
Author(s):  
YUHONG GUO ◽  
YUNKE WU ◽  
SHUNPING HE ◽  
HAITAO Shi ◽  
ERMI ZHAO

The taxonomy of the Asian snail-eating snakes (Pareatidae) is an ongoing controversy, partly because morphological characters do not yield consistent results across studies. We infer phylogenetic relationships within Pareatidae using ~ 2 kilobases of DNA sequences including two mitochondrial (cyt b and ND4) and one nuclear gene (c-mos). Results reveal four major lineages: Aplopeltura, Asthenodipsas, a clade formed by Pareas carinatus and P. nuchalis, and a clade comprising all other species of Pareas sampled in this study. Our data do not have enough signal to either support or reject a monophyletic Pareas. However, large molecular divergence (16.5%) is observed between the two major clades of Pareas, a level that is comparable to that between Pareas and Aplopeltura. Scale characters also suggest that P. carinatus and P. nuchalis are distinct from congeners, and future morphological and/or molecular studies might assess whether a distinct genus should be recognized. The molecular phylogeny further suggests a distant relationship between P. chinensis and P. formosensis and supports the validity of the former species.


2020 ◽  
Author(s):  
Jorge Flores ◽  
Alexander C. Bippus ◽  
Alexandru Tomescu ◽  
Neil Bell ◽  
Jaakko Hyvönen

AbstractWhen fossils are sparse and the lineages studied are very divergent morphologically, analyses based exclusively on morphology may lead to conflicting and unexpected hypotheses. Through integration of data from conservative genes/gene regions the terminals including these data can anchor or constrain the search, thereby practically circumscribing the search space of the combined analyses. In this study, we revisit the phylogeny of a highly divergent group of mosses, class Polytrichopsida. We supplemented the morphological matrix by adding sequence data of the nuclear gene 18S, chloroplast genes rbcL and rps4, plus the mitochondrial gene nad5. For the phylogenetic analyses we used parsimony as the optimality criterion. Analyses that included all the terminals resulted in one most parsimonious tree with a clade comprised of Alophosia azorica and the fossil Meantoinea alophosioides representing the basal-most lineage. Analyses with different outgroup sampling produced the same topology for most ingroup relationships. An analysis excluding morphological characters and the four terminals for which only morphological characters were scored (the two fossil and two extant terminals) resulted in one optimal tree with identical topology to the one obtained when including all terminals. These results are largely congruent with those obtained in the recent analyses based exclusively on sequence level data of a larger number of terminals. Our results indicate that large size and complexity of the gametophyte have evolved independently in several lineages. Notably, the nodes of the backbone of the most parsimonious tree have very low support values, thus these inferred relationships could change if new additional information conflicts with the current data. Future studies should be aimed at incorporating all terminals into phylogenetic analyses, which is not an unrealistic goal for a group with less than 200 species. Also, additional fossils, some of which await detailed examination and description, need to be included. Whether these will affect the overall pattern of phylogeny presented here remains to be seen. In a group that is obviously very ancient, we cannot assume, a priori, that currently known fossil taxa, which go back in time less than 140 Ma, represent the oldest lineages of the group.


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