Monophyly and phylogenetic relationships of Thereva and therevine genus-groups (Insecta:Diptera:Therevidae) based on EF-1α, 28S rDNA and mitochondrial 16S rDNA sequences

2007 ◽  
Vol 21 (3) ◽  
pp. 279 ◽  
Author(s):  
Kevin C. Holston ◽  
Michael E. Irwin ◽  
Brian M. Wiegmann
Keyword(s):  
16S Rdna ◽  
Phylogenetic Relationships ◽  
Phylogenetic Signal ◽  
Phylogenetic Analyses ◽  
28S Rdna ◽  
Partial Recovery ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Holarctic Region ◽  
Species Groups

Phylogenetic analyses using 28S rDNA, elongation factor (EF)-1α, and mt 16S rDNA sequences were performed to test the monophyly of Thereva Latreille. Two of the three Afrotropical Thereva species groups lack the genitalia characters that unambiguously diagnose Thereva in the Holarctic Region, but phylogenetic relationships among Thereva species groups and therevine genera are poorly understood. Using an extensive taxonomic sample (39 of the 62 therevine genera) and Thereva, sensu lato (15 spp.), simultaneous analyses of all three gene partitions recovered Nearctic and Palaearctic Thereva species in a well supported clade that includes the Afrotropical seminitida-group but excludes the Afrotropical analis- and turneri-groups. Stronger phylogenetic signal from the EF-1α partition, measured by the skewness statistic and proportion of total parsimony informative characters, dominated conflicting signal from the 16S partition and weaker, but more congruent, signal from 28S. Reducing the taxonomic sample in analyses of Therevinae reduced homoplasy, increased phylogenetic structure and partitioned Bremer support values and reduced incongruence with 28S for the 16S partition. Although molecular analyses yielded partial recovery of informal therevine genus-groups, morphological diagnoses of higher-level groups are poorly supported with the exception of Cyclotelini. The ‘Holarctic radiation’ refers to a diverse clade of genera closely related to Pandivirilia Irwin & Lyneborg and Acrosathe Irwin & Lyneborg widely distributed throughout the Holarctic Region that is the sister-group to Thereva, sensu stricto. Results from these analyses underscore the importance of male and female genitalia characters in recognising monophyletic groups and regional endemism in therevine diversification.

scholarly journals Testing the higher-level phylogenetic classification of Digenea (Platyhelminthes, Trematoda) based on nuclear rDNA sequences before entering the age of the ‘next-generation’ Tree of Life

2019 ◽  
Vol 93 (3) ◽  
pp. 260-276 ◽  
Author(s):  
G. Pérez-Ponce de León ◽  
D.I. Hernández-Mena
Keyword(s):  
Phylogenetic Relationships ◽  
Phylogenetic Signal ◽  
28S Rdna ◽  
Rrna Genes ◽  
Rrna Gene ◽  
28S Rrna ◽  
Next Generation ◽  
Phylogenetic Classification ◽  
Rdna Sequences

AbstractDigenea Carus, 1863 represent a highly diverse group of parasitic platyhelminths that infect all major vertebrate groups as definitive hosts. Morphology is the cornerstone of digenean systematics, but molecular markers have been instrumental in searching for a stable classification system of the subclass and in establishing more accurate species limits. The first comprehensive molecular phylogenetic tree of Digenea published in 2003 used two nuclear rRNA genes (ssrDNA = 18S rDNA and lsrDNA = 28S rDNA) and was based on 163 taxa representing 77 nominal families, resulting in a widely accepted phylogenetic classification. The genetic library for the 28S rRNA gene has increased steadily over the last 15 years because this marker possesses a strong phylogenetic signal to resolve sister-group relationships among species and to infer phylogenetic relationships at higher levels of the taxonomic hierarchy. Here, we have updated the database of 18S and 28S rRNA genes until December 2017, we have added newly generated 28S rDNA sequences and we have reassessed phylogenetic relationships to test the current higher-level classification of digeneans (at the subordinal and subfamilial levels). The new dataset consisted of 1077 digenean taxa allocated to 106 nominal families for 28S and 419 taxa in 98 families for 18S. Overall, the results were consistent with previous higher-level classification schemes, and most superfamilies and suborders were recovered as monophyletic assemblages. With the advancement of next-generation sequencing (NGS) technologies, new phylogenetic hypotheses from complete mitochondrial genomes have been proposed, although their power to resolve deep levels of trees remains controversial. Since data from NGS methods are replacing other widely used markers for phylogenetic analyses, it is timely to reassess the phylogenetic relationships of digeneans with conventional nuclear rRNA genes, and to use the new analysis to test the performance of genomic information gathered from NGS, e.g. mitogenomes, to infer higher-level relationships of this group of parasitic platyhelminths.

scholarly journals Clover Proliferation Group (16SrVI) Subgroup A (16SrVI-A) Phytoplasma is a Probable Causal Agent of Potato Purple Top Disease in Washington and Oregon

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 429-429 ◽  
Author(s):  
I.-M. Lee ◽  
K. D. Bottner ◽  
J. E. Munyaneza ◽  
G. A. Secor ◽  
N. C. Gudmestad
Keyword(s):  
16S Rdna ◽  
Phylogenetic Analyses ◽  
Nested Polymerase Chain Reaction ◽  
Axillary Shoots ◽  
Rdna Sequences ◽  
Etiological Role ◽  
16S Rdna Sequences ◽  
Purple Top Disease ◽  
Potato Purple Top ◽  
Potato Seedlings

An epidemic of purple top disease of potato (Solanum tuberosum) occurred in the Columbia Basin Region of Washington and Oregon in 2002 and 2003, causing great economic loss in the potato industry (1). Symptoms of potato purple top (PPT) were characterized by upright terminal shoots, upward leaf rolling, chlorosis, red or purplish discoloration of new leaves, proliferation of axillary shoots with basal swelling, and the formation of aerial tubers. Preliminary studies on PPT disease suggested phytoplasma as a possible cause (1). In this study, 78 potato samples (including five asymptomatic) were collected from five fields throughout the region. A nested polymerase chain reaction (PCR) with primer pair P1/P7 in the first amplification followed with primer pair R16F2n/R16R2 was performed to detect the presence of phytoplasmas in infected plants (2). Restriction fragment length polymorphism (RFLP) and phylogenetic analyses of amplified 16S rDNA sequences were used for phytoplasma identification. Eighty-four percent (63% in the first amplification) of the symptomatic samples and 60% (0% in the first amplification) of the asymptomatic samples tested positive. Low phytoplasma titers and the presence of PCR inhibitors accounts for the low detection rate in the first PCR amplifications. RFLP analyses of 16S rDNA with enzymes MseI, AluI, HhaI, RsaI, and HpaII indicated that the phytoplasma associated with PPT belonged to the clover proliferation (CP) group (16SrVI) subgroup A (16SrVI-A) (2). 16SrVI-A currently consists of three members, CP (GenBank Accession No. AY500130), potato witches'-broom (GenBank Accession No. AY500818), and vinca virescence (VR) (GenBank Accession No. AY500817), a strain of beet leafhopper-transmitted virescence agent (BLTVA) phytoplasma (2). The taxonomic affiliation of PPT phytoplasma was confirmed by phylogenetic analysis of cloned 16S rDNA (GenBank Accession Nos. PPT4, AY496004; PPT8, AY496005). The 16S rDNA sequences of the PPT strains were closely related to VR with 99.7% sequence homology compared with 99.2% with CP. A high correlation between the symptoms and the presence of 16SrVI-A phytoplasmas in the potato plants suggests that these phytoplasmas play an etiological role in PPT disease. To gain further evidence, a modified test of Koch's postulates was conducted. Infected tissues from four phytoplasma-positive potato samples (including PPT4 and PPT8) were grafted onto healthy potato seedlings. Within 60 days after grafting, the potato seedlings developed symptoms similar to those in the original diseased samples. The newly infected plants were maintained through cuttings. RFLP analysis of 16S rDNA indicated that the phytoplasmas detected in each of the seedlings and cuttings were identical to those in the scions. These results confirmed the probable etiological role of CP group, subgroup 16SrVI-A phytoplasma strains in PPT disease in Washington and Oregon. There are two other confirmed cases of phytoplasmas (BLTVA and aster yellows phytoplasma) associated with PPT disease in Utah (4) and Mexico (3). References: (1) P. B. Hamm et al. Potato Prog. Vol. 3, No. 1, 2003. (2) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (3) N. E. Leyva-Lopez et al. Can. J. Microbiol. 48:1062, 2002. (4) C. D. Smart et al. Phytopathology 83:1399, 1993.

scholarly journals 16S rDNA sequences and phylogenetic analyses ofMicrocystisstrains with and without phycoerythrin

1998 ◽  
Vol 164 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Shigeto Otsuka ◽  
Shoichiro Suda ◽  
Renhui Li ◽  
Masayuki Watanabe ◽  
Hiroshi Oyaizu ◽  
...  
Keyword(s):  
16S Rdna ◽  
Phylogenetic Analyses ◽  
Rdna Sequences ◽  
16S Rdna Sequences

scholarly journals Shewanella gaetbuli sp. nov., a slight halophile isolated from a tidal flat in Korea

2004 ◽  
Vol 54 (2) ◽  
pp. 487-491 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Kook Hee Kang ◽  
Tae-Kwang Oh ◽  
Yong-Ha Park
Keyword(s):  
16S Rdna ◽  
Tidal Flat ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Phenotypic Properties ◽  
16S Rdna Sequence ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Isoprenoid Quinones ◽  
Type Strains

A Gram-negative, motile, non-spore-forming, rod-shaped strain, TF-27T (=KCCM 41648T=JCM 11814T), was isolated from a tidal flat in Korea. This organism grew well at 25–35 °C, with optimum growth at 30 °C. Strain TF-27T grew optimally in the presence of 2 % NaCl; it did not grow without NaCl or in the presence of >8 % NaCl. Strain TF-27T simultaneously contained both menaquinones and ubiquinones as isoprenoid quinones. The predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The major fatty acids in strain TF-27T were iso-C15 : 0 (20·6 %) and iso-C15 : 0 2-OH and/or C16 : 1 ω7c (21·1 %). The DNA G+C content of strain TF-27T was 42 mol%. Phylogenetic analyses based on 16S rDNA sequences showed that strain TF-27T falls within the radiation of the cluster that is encompassed by the genus Shewanella. Levels of 16S rDNA sequence similarity between strain TF-27T and the type strains of Shewanella species were 93·2–96·8 %. On the basis of phenotypic properties and phylogenetic data, strain TF-27T should be placed in the genus Shewanella as a novel species, for which the name Shewanella gaetbuli sp. nov. is proposed.

Phylogenetic relationships of the lower Cyclorrhapha (Diptera: Brachycera) based on 28S rDNA sequences

2002 ◽  
Vol 33 (4) ◽  
pp. 445-456 ◽  
Author(s):  
Brian M. Wiegmann ◽  
Kenneth P. Collins
Keyword(s):  
Phylogenetic Analysis ◽  
Phylogenetic Relationships ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
28S Rdna ◽  
Morphological Data ◽  
Monophyletic Clade ◽  
Rdna Sequences ◽  
28S Rdna Sequences

AbstractCyclorrhaphan Diptera are an extremely successful clade of ecologically and phylogenenetically important flies. Despite their significance the relationships among lower cyclorrhaphans ('Aschiza') remain controversial in spite of several morphologically based phylogenetic analyses. We sequenced a 2.7-kb fragment of 28S rDNA for taxa representing all lower cyclorrhaphan families (except Ironomyiidae), four schizophoran families, and seven empidoid out-group taxa. Phylogenetic analysis of these data strongly supports a monophyletic Cyclorrhapha (including the enigmatic taxon Opetia nigra) that is divided into two clades - a well-supported Eumuscomorpha (Syrphidae + Pipunculidae + Schizophora), and a weakly-supported Platypezoidea (all non-Eumuscomorpha). Consequently, the former grouping known as Aschiza, which included syrphids and pipunculids, is not a valid monophyletic clade. Within Platypezoidea, most of our analyses place Lonchopteridae as sister group to Opetiidae, and strongly support the monophyly of Sciadoceridae + Phoridae. Among the Eumuscomorpha we do not recover the monophyly of Syrphoidea (Syrphidae + Pipunculidae). Instead, all analyses place Pipunculidae as the sister group to Schizophora. This novel finding has never been proposed based on morphological data and will require more data (both molecular and morphological) and taxa to confirm.

scholarly journals Phylogenetic Analysis of Nonthermophilic Members of the Kingdom Crenarchaeota and Their Diversity and Abundance in Soils

1998 ◽  
Vol 64 (11) ◽  
pp. 4333-4339 ◽  
Author(s):  
Daniel H. Buckley ◽  
Joseph R. Graber ◽  
Thomas M. Schmidt
Keyword(s):  
16S Rrna ◽  
16S Rdna ◽  
Phylogenetic Analyses ◽  
Pcr Primers ◽  
Soil Samples ◽  
Molecular Techniques ◽  
Rrna Gene ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Long Term Ecological Research

ABSTRACT Within the last several years, molecular techniques have uncovered numerous 16S rRNA gene (rDNA) sequences which represent a unique and globally distributed lineage of the kingdom Crenarchaeotathat is phylogenetically distinct from currently characterized crenarchaeotal species. rDNA sequences of members of this novel crenarchaeotal group have been recovered from low- to moderate-temperature environments (−1.5 to 32°C), in contrast to the high-temperature environments (temperature, >80°C) required for growth of the currently recognized crenarchaeotal species. We determined the diversity and abundance of the nonthermophilic members of the Crenarchaeota in soil samples taken from cultivated and uncultivated fields located at the Kellogg Biological Station’s Long-Term Ecological Research site (Hickory Corners, Mich.). Clones were generated from 16S rDNA that was amplified by using broad-specificity archaeal PCR primers. Twelve crenarchaeotal sequences were identified, and the phylogenetic relationships between these sequences and previously described crenarchaeotal 16S rDNA sequences were determined. Phylogenetic analyses included nonthermophilic crenarchaeotal sequences found in public databases and revealed that the nonthermophilic Crenarchaeota group is composed of at least four distinct phylogenetic clusters. A 16S rRNA-targeted oligonucleotide probe specific for all known nonthermophilic crenarchaeotal sequences was designed and used to determine their abundance in soil samples. The nonthermophilicCrenarchaeota accounted for as much as 1.42% ± 0.42% of the 16S rRNA in the soils analyzed.

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