Intragenomic internal transcribed spacer 2 variation in a genus of parasitoid wasps (Hymenoptera: Braconidae): implications for accurate species delimitation and phylogenetic analysis

2019 ◽  
Author(s):  
E. P. Fagan‐Jeffries ◽  
S. J. B. Cooper ◽  
T. M. Bradford ◽  
A. D. Austin
Keyword(s):  
Phylogenetic Analysis ◽  
Species Delimitation ◽  
Internal Transcribed Spacer ◽  
Parasitoid Wasps ◽  
Internal Transcribed Spacer 2

Evolution and function of B chromosome 45S rDNA sequences in Brachycome dichromosomatica

Genome ◽  
2007 ◽  
Vol 50 (7) ◽  
pp. 638-644 ◽  
Author(s):  
Sylvia Marschner ◽  
Armin Meister ◽  
Frank R. Blattner ◽  
Andreas Houben
Keyword(s):  
Phylogenetic Analysis ◽  
Internal Transcribed Spacer ◽  
B Chromosome ◽  
Its2 Sequence ◽  
B Chromosomes ◽  
Rrna Gene ◽  
45S Rdna ◽  
Internal Transcribed Spacer 2 ◽  
Rdna Sequences ◽  
And Function

The origin and activity of 45S rDNA located on micro B chromosomes of the daisy Brachycome dichromosomatica were analysed. The internal transcribed spacer 2 (ITS2) of the 45S rRNA gene was sequenced for micro B, large B, and A chromosomes of B. dichromosomatica cytodeme A2, and conserved differences were identified between sequences originating from A and both types of B chromosomes. Phylogenetic analysis did not identify a species containing an ITS2 sequence more similar to either of the B chromosome sequences than the B. dichromosomatica A chromosome sequences. Thus, an origin of the B chromosomes from A chromosomes at a time prior to the divergence of the 4 cytodemes of B. dichromosomatica is suggested. The frequent (70%) nucleolar non-association of micro B chromosomes suggests inactivity of micro B 45S rDNA.

scholarly journals Variation and Diagnostic Power of the Internal Transcribed Spacer 2 in Mediterranean and Atlantic Eolid Nudibranchs (Mollusca, Gastropoda)

2021 ◽  
Vol 8 ◽  
Author(s):  
Matteo Garzia ◽  
Paolo Mariottini ◽  
Daniele Salvi ◽  
Giulia Furfaro
Keyword(s):  
Species Delimitation ◽  
Internal Transcribed Spacer ◽  
Morphological Characters ◽  
Marine Biodiversity ◽  
Cryptic Diversity ◽  
Nuclear Marker ◽  
Nuclear Markers ◽  
Closely Related Species ◽  
Internal Transcribed Spacer 2 ◽  
Mitochondrial Markers

Mediterranean marine biodiversity is still underestimated especially for groups such as nudibranchs. The identification of nudibranchs taxa is challenging because few morphological characters are available and among them chromatic patterns often do not align with species delimitation. Molecular assessments helped unveiling cryptic diversity within nudibranchs and have been mostly based on mitochondrial markers. Fast evolving nuclear markers are much needed to complement phylogenetic and systematic assessments at the species and genus levels. Here, we assess the utility of the nuclear Internal Transcribed Spacer 2 (ITS2) to delimit species in the eolid nudibranchs using both primary and secondary structures. Comparisons between the variation observed at the ITS2 and at the two commonly used mitochondrial markers (COI and 16S) on 14 eolid taxa from 10 genera demonstrate the ability of ITS2 to detect congeneric, closely related, species. While ITS2 has been fruitfully used in several other mollusc taxa, this study represents the first application of this nuclear marker in nudibranchs.

scholarly journals The new Internal Transcribed Spacer 2 diagnostic tool clarifies the taxonomic position and geographic distribution of the North American malaria vector Anopheles punctipennis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
James M. Hodge ◽  
Andrey A. Yurchenko ◽  
Dmitriy A. Karagodin ◽  
Reem A. Masri ◽  
Ryan C. Smith ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Internal Transcribed Spacer ◽  
Single Species ◽  
Its2 Sequence ◽  
Pathogen Transmission ◽  
Molecular Diagnostic ◽  
Diagnostic Tools ◽  
Sequence Length ◽  
Phylogenetic Position ◽  
Internal Transcribed Spacer 2

Abstract Background The malaria mosquito Anopheles punctipennis, a widely distributed species in North America, is capable of transmitting human malaria and is actively involved in the transmission of the ungulate malaria parasite Plasmodium odocoilei. However, molecular diagnostic tools based on Internal Transcribed Spacer 2 (ITS2) of ribosomal DNA are lacking for this species. Anopheles punctipennis is a former member of the Anopheles maculipennis complex but its systematic position remains unclear. Methods In this study, ITS2 sequences were obtained from 276 An. punctipennis specimens collected in the eastern and midwestern United States and a simple and robust Restriction Fragment Length Polymorphism approach for species identification was developed. The maximum-likelihood phylogenetic tree was constructed based on ITS2 sequences available through this study and from GenBank for 20 species of Anopheles. Results The analysis demonstrated a consistent ITS2 sequence length and showed no indications of intragenomic variation among the samples based on ITS2, suggesting that An. punctipennis represents a single species in the studied geographic locations. In this study, An. punctipennis was found in urban, rural, and forest settings, suggesting its potential broad role in pathogen transmission. Phylogeny based on ITS2 sequence comparison demonstrated the close relationship of this species with other members of the Maculipennis group. Conclusions This study developed molecular tools based on ITS2 sequences for the malaria vector An. punctipennis and clarified the phylogenetic position of the species within the Maculipennis group.

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