SEQUENCE VARIATION OF THE RIBOSOMAL DNA SECOND INTERNAL TRANSCRIBED SPACER REGION IN TWO SPATIALLY DISTINCT POPULATIONS OF AMBLYOMMA AMERICANUM (L.) (ACARI: IXODIDAE)

2005 ◽  
Vol 91 (2) ◽  
pp. 260-263 ◽  
Author(s):  
M. V. Reichard ◽  
A. A. Kocan ◽  
R. A. Van Den Bussche ◽  
R. W. Barker ◽  
J. H. Wyckoff ◽  
...  
Keyword(s):  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Sequence Variation ◽  
Amblyomma Americanum ◽  
Internal Transcribed Spacer Region ◽  
Second Internal Transcribed Spacer

scholarly journals A new subfamily for a clade of opecoelids (Trematoda: Digenea) exploiting marine fishes as second-intermediate hosts, with the first report of opecoelid metacercariae from an elasmobranch

2019 ◽  
Author(s):  
Storm Blas Martin ◽  
Abigail Jayne Downie ◽  
Thomas Herbert Cribb
Keyword(s):  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Marine Fishes ◽  
Barrier Reef ◽  
Intermediate Hosts ◽  
Internal Transcribed Spacer Region ◽  
Epaulette Shark ◽  
The Family ◽  
Unidentified Species ◽  
Second Internal Transcribed Spacer

Abstract Metacercariae of trematodes belonging to the family Opecoelidae were collected from small fishes of the Great Barrier Reef: a blenniid, two gobiids, two labrids, three pomacentrids, a monacanthid, an ostraciid and the epaulette shark, Hemiscyllium ocellatum. Sequences of the second internal transcribed spacer region (ITS2) of ribosomal DNA were generated from these metacercariae in an attempt to match them with adult worms. Three species of Allopodocotyle (Allopodocotyle epinepheli, Allopodocotyle heronensis and an unidentified species), two unidentified species of Hamacreadium and Pacificreadium serrani were detected. Among the Opecoelidae, these species all resolve to a single, phylogenetically and somewhat morphologically distinct clade. Species of this clade are the only known marine opecoelids to exploit fishes as second-intermediate hosts. The clade is proposed to warrant a new subfamily, the Hamacreadiinae subfam. nov. It includes Allopodocotyle, Bentholebouria, Cainocreadium, Choanotrema, Hamacreadium, Pacificreadium, Paraplagioporus, Pedunculacetabulum and Podocotyloides.

scholarly journals Intragenomic sequence variations in the second internal transcribed spacer (ITS2) ribosomal DNA of the malaria vector Anopheles stephensi

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253173
Author(s):  
Shobhna Mishra ◽  
Gunjan Sharma ◽  
Manoj K. Das ◽  
Veena Pande ◽  
Om P. Singh
Keyword(s):  
Molecular Marker ◽  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Sequence Variation ◽  
Anopheles Stephensi ◽  
28S Rdna ◽  
Reference Sequence ◽  
Its2 Region ◽  
Intragenomic Variation ◽  
Second Internal Transcribed Spacer

Second Internal Transcribed Spacer (ITS2) ribosomal DNA (rDNA) sequence is a widely used molecular marker for species-identification or -delimitation due to observed concerted evolution which is believed to homogenize rDNA copies in an interbreeding population. However, intra-specific differences in ITS2 of Anopheles stephensi have been reported. This study reports the presence of intragenomic sequence variation in the ITS2-rDNA of An. stephensi and hypothesizes that observed intra-specific differences in this species may have resulted due to ambiguous DNA sequence-chromatogram resulting from intragenomic heterogeneity. Anopheles stephensi collected from different parts of India were sequenced for complete ITS2 and the variable region of 28S-rDNA (d1-d3 domains). Intragenomic variations were found in ITS2 region of all An. stephensi sequenced, but no such variation was observed in d1 to d3 domains of 28S-rDNA. Cloning and sequencing of ITS2 through the d3 domain of the 28S region of rDNA from representative samples from northern, central, and southern India confirmed the presence of intragenomic variation in ITS2 due to transitions at three loci and two bp indel in a di-nucleotide microsatellite locus. Multiple haplotypes were observed in ITS2 raised from such variations. Due to the absence of detectable intragenomic sequence variation in the d1 to d3 domain of 28S rDNA of An. stephensi, this region can serve as an ideal reference sequence for taxonomic and phylogenetic studies. The presence of intragenomic variation in rDNA should be carefully examined before using this as a molecular marker for species delimitation or phylogenetic analyses.

scholarly journals Intragenomic variation in the second internal transcribed spacer of the ribosomal DNA of species of the genera Culex and Lutzia (Diptera: Culicidae)

2011 ◽  
Vol 106 (1) ◽  
pp. 01-08 ◽  
Author(s):  
Fabiana Tavares Vesgueiro ◽  
Bruna Demari-Silva ◽  
Rosely dos Santos Malafronte ◽  
Maria Anice Mureb Sallum ◽  
Mauro Toledo Marrelli
Keyword(s):  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Intragenomic Variation ◽  
Second Internal Transcribed Spacer

scholarly journals Sequences of the second internal transcribed spacer of ribosomal DNA for three species of Trichostrongylus (Nematoda: Trichostrongylidae) from sheep in Russia

2007 ◽  
Vol 44 (2) ◽  
pp. 43-46 ◽  
Author(s):  
D. Kuznetsov ◽  
N. Kuznetsova
Keyword(s):  
Dna Sequence ◽  
Intraspecific Variation ◽  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Sequence Data ◽  
Moscow Region ◽  
Dna Sequence Data ◽  
Interspecific Differences ◽  
Second Internal Transcribed Spacer ◽  
First Time

AbstractFor the first time, DNA sequence data were obtained for three species of Trichostrongylus from Russia. Internal transcribed spacer (ITS-2) of ribosomal DNA was sequenced for T. axei, T. colubriformis and T. probolurus from sheep from the Moscow region. ITS-2 rDNA length was estimated as 238 nucleotides for T. colubriformis and T. probolurus and 237 nucleotides for T. axei. The G+C content of the ITS-2 sequences of T. colubriformis, T. axei and T. probolurus were 31 %, 32 % and 34 % respectively. The level of interspecific differences in ITS-2 of rDNA of T. axei, T. probolurus and T. colubriformis ranged from 3 to 4 %. The ITS-2 sequences from the Russian specimens were compared with those of T. axei, T. probolurus and T. colubriformis from Australia and Germany. Intraspecific variation ranged from 0 % in T. colubriformis to 3.0 % in T. axei.

Minimal intraspecific variation in the sequence of the transcribed spacer regions of the ribosomal DNA of lake trout (Salvelinus namaycush)

Genome ◽  
1994 ◽  
Vol 37 (4) ◽  
pp. 664-671 ◽  
Author(s):  
Lang Zhuo ◽  
S. L. Sajdak ◽  
R. B. Phillips
Keyword(s):  
Polymerase Chain Reaction ◽  
Intraspecific Variation ◽  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Lake Trout ◽  
Intergenic Spacer ◽  
Coding Region ◽  
Chain Reaction ◽  
Internal Transcribed Spacer Region ◽  
Polymerase Chain

Intraspecific variation in the sequence of the transcribed spacer regions of the ribosomal DNA (rDNA) in lake trout was examined by restriction mapping and sequencing of these regions amplified by the polymerase chain reaction. The length of the first internal transcribed spacer region (ITS-1) was 566 bases and the second internal transcribed spacer region (ITS-2) was 368 bases in lake trout. When the 1.4-kb region including the ITS-1, the 5.8S coding region, and the ITS-2 was amplified from 12 individuals from four populations and digested with eight different enzymes only one intraindividual polymorphism was found that occurred in each population. When the amplified ITS-1 region was sequenced from an additional 10 individuals from five populations, no interindividual variation was found in the sequence. A 6-kb portion of the rDNA repeat unit including 1.6 kb of the 18S coding region, the 5′ external spacer region (5′ ETS), and part of the adjacent intergenic spacer was cloned and a restriction map was prepared for these regions in lake trout. No intraspecific variation was found in the region adjacent to the 18S rDNA, which includes the 5′ ETS, although intraspecific and intraindividual length variation was found in the intergenic spacer region 3–6 kb from the 18S. Sequencing of a 609-b segment of the 5′ ETS adjacent to the 18S coding region revealed the presence of two 41-b repeats. The 198-b sequence between the repeats had some similarity to the 18S coding region of other fishes. Primers were designed for amplification of 559 b of the 5′ ETS using the polymerase chain reaction. No intraspecific variation in this region in lake trout was found when the DNA amplified from this region in 12 individuals from four populations was digested with eight restriction enzymes.Key words: ribosomal DNA, internal transcribed spacer regions, 5′ external spacer region, transcribed spacer, lake trout.

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