Sequence Variation in the Ribosomal DNA Internal Transcribed Spacer of Tridacna crocea

2000 ◽  
Vol 2 (6) ◽  
pp. 511-516 ◽  
Author(s):  
Eizadora T. Yu ◽  
Ma. Antonette Juinio-Meñez ◽  
Virginia D. Monje
Keyword(s):  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Sequence Variation ◽  
Tridacna Crocea

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 Intra- and inter-specific variation in nuclear ribosomal internal transcribed spacer 1 of the Schistosoma japonicum species complex

Parasitology ◽  
1998 ◽  
Vol 116 (4) ◽  
pp. 311-317 ◽  
Author(s):  
L. VAN HERWERDEN ◽  
D. BLAIR ◽  
T. AGATSUMA
Keyword(s):  
Schistosoma Japonicum ◽  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Species Complex ◽  
Sequence Variation ◽  
Nuclear Ribosomal Dna ◽  
Single Individual ◽  
Repeat Sequences ◽  
Dna Repeat ◽  
Specific Variation

The first internal transcribed spacer (ITS1) of the nuclear ribosomal DNA repeat was sequenced for members of the Schistosoma japonicum species complex (S. malayensis, S. mekongi and 2 geographical isolates of S. japonicum). The ITS1 is composed of 3 distinct regions: the 5′ end (23 nucleotides); a tract of approximately 90–140 nucleotides, which occurs up to 7 times in tandem, the number varying even within an individual in all species investigated in this study; the 3′ region (378 nucleotides), which lacks repeats. There is size and sequence variation among copies of the ITS1 repeat within a single individual. The relative abundances of size variants of ITS1 in S. japonicum have been ascertained by hybridizing genomic digests with an ITS1 probe. Multiple repeats and intra-individual variation in numbers and abundance of these is a feature of the Asian schistosomes, but not generally of African schistosomes. Possible reasons for this difference in ITS1 between African and Asian schistosomes are discussed. The ITS1 repeat sequences described for African schistosomes are different to, and cannot be aligned with, those from the Asian species described here, whereas the remainder of the ITS1 can be aligned quite easily.

scholarly journals Sequence variation of Ribosomal DNA Internal Transcribed Spacer 1 of four common carp populations

2011 ◽  
Vol 23 (2) ◽  
pp. 271-276
Author(s):  
ZHONG Liqiang ◽  
◽  
ZHANG Chengfeng ◽  
ZHOU Kai ◽  
LI Bing ◽  
...  
Keyword(s):  
Common Carp ◽  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Sequence Variation

Identification of Vietnamese native Dendrobium species based on ribosomal DNA internal transcribed spacer sequence

2018 ◽  
Vol 10 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Tran Duy Duong ◽  
Khuat Huu Trung ◽  
La Tuan Nghia ◽  
Nguyen Thi Thanh Thuy ◽  
Pham Bich Hien ◽  
...  
Keyword(s):  
Ribosomal Dna ◽  
Internal Transcribed Spacer

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
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